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The progress on Electrochemical CO2-to-Formate Conversion by p-Block Metal Based Catalysts

Fengshou Yu , Jiayu Zhan , Lu-Hua Zhang

Progress in Chemistry ›› 2022, Vol. 34 ›› Issue (4) : 983 -991.

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Progress in Chemistry ›› 2022, Vol. 34 ›› Issue (4) : 983-991 DOI: 10.7536/PC210122
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The progress on Electrochemical CO2-to-Formate Conversion by p-Block Metal Based Catalysts
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Abstract

Electrochemical CO2 reduction to value added chemical feedstocks and fuels driven by renewable electricity gives a promising and appealing approach to address the global challenges in energy and sustainability and eventually close the anthropogenic carbon cycle. The most crucial step for this conversion is to develop robust electrocatalysts promoting adsorption of CO2 molecule and subsequent activation with low energy barriers. Due to the different overpotentials and electron transfer amount needed for various reduction products, there is huge gap of producing price among a variety of products. Based on recent research, formic acid (or formate) is one of the most economically viable and useful reduction product in a couple of chemical processes. In this paper, starting with fundamental understanding of reaction mechanism, we review the main progress of p-block post-transition metal (e.g., Sn, Bi, and In) based electrocatalysts for electrochemical CO2 reduction to produce formic acid. In addition, strategies to facilitate the catalytic performance of CO2 to formic acid) conversion including reduction conversion of metal oxides, morphology control, doping and alloying to modulate the electronic structure are also be briefly reviewed. Finally, we summarize the existing challenges and present perspectives for the future development of this exciting field.

Contents

1 Introduction

2 The mechanism of CO2-to-formate conversion

3 p-block metal-based catalysts

3.1 Sn-based catalysts

3.2 Bi-based catalysts

3.3 In-based catalysts

4 Conclusion and outlook

Graphical abstract

Keywords

carbon dioxide / electrochemical / reduction / catalysis / formic acid / p-block metals

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Fengshou Yu, Jiayu Zhan, Lu-Hua Zhang. The progress on Electrochemical CO2-to-Formate Conversion by p-Block Metal Based Catalysts. Progress in Chemistry, 2022, 34(4): 983-991 DOI:10.7536/PC210122

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1 Introduction

In May 2019, the National Oceanic and Atmospheric Administration (NOAA) reported that the concentration of CO2 in the atmosphere had exceeded 415 ppm, the highest ever recorded. NOAA said that if the Earth is compared to a fireplace that emits heat, then CO2 is a "brick". Excessive greenhouse gases such as CO2 in the atmosphere will absorb the heat emitted by land and ocean, which will unbalance the Earth's thermal cycle and lead to global temperature rise. From another point of view, CO2 are economic, safe and sustainable C1 resources. Therefore, it will be the main theme of carbon science and technology in the future to develop efficient CO2 conversion technology, convert it into high value-added chemicals or chemical fuels, realize the resource utilization of CO2, and promote the balance of carbon cycle in nature[1,2].
CO2 is a typical linear symmetric triatomic molecule, in which the two sp hybrid orbitals of the carbon atom form two σ bonds with the 2px orbitals of two oxygen atoms (assuming that the CO2 molecule is placed along the X axis) in a head-to-head manner. At this time, the carbon atom has two 2p orbitals left which are not involved in hybridization, and they are located on the y-axis and z-axis, namely the 2py and 2pz orbitals. They overlap with the 2p orbitals of the oxygen atoms on both sides from the side by shoulder to shoulder, forming two stable three-center four-electron p-p delocalized large π bonds ( π 3 4). The π 3 4 belongs to the non-bonding orbital, and its electron cloud is mainly bound to two oxygen atoms, which have large electronegativity, so the reactivity of the two pairs of electrons in the highest occupied molecular orbital is relatively poor. The carbon atom is an electron-deficient center, which can act as an electrophile and react with nucleophiles and electron-bearing groups. From the above analysis, we know that the effective way of CO2 activation is to input electrons in an appropriate way, or to take electrons from other molecules in the reaction process, that is, to use them as oxidants. At present, the conversion technologies of CO2 mainly include chemical reduction, photocatalytic conversion, photoelectrocatalytic conversion and electrochemical reduction[3⇓⇓~6].
Among many CO2 catalytic conversion technologies, electrocatalytic reduction of CO2 is a process in which CO2 molecules or CO2 solvated ions in solution obtain electrons from the electrode surface for reduction. This reduction process will undergo 2, 4, 6, 8, 12, 14, and 18 electron transfer at different potentials, resulting in a series of products,Including CO, HCOOH, HCHO, CH3OH, CH4,C2H4, C2H5OH, C2H6 and C3H7OH, etc[7,8]. Due to the different reduction potential and reaction mechanism of different products, the production cost of unit product is also different. Although C2+ products have high industrial value, the preparation of C2+ products by electrocatalytic reduction of CO2 involves multi-step proton-coupled electron transfer process, which often requires high overpotential.Under these conditions, the proton reduction reaction becomes violent, so it is difficult to achieve the desired selectivity of the C2+ product, which ultimately leads to large energy consumption, difficult separation and high production cost of the product, which is still a huge challenge at the industrial level[9]. In contrast, a series of recent technical analyses have shown that HCOOH is one of the most economically and practically valuable among all electrochemical CO2 reduction products (Fig. 1)[10].
As a basic chemical raw material, HCOOH is widely used in pesticide, leather, rubber and other industries. In addition, the reduction product of liquid CO2, HCOOH, does not need to be separated and can be directly used as fuel for fuel cells, showing more potential application prospects than methanol fuel[11,12]. In recent years, the demand for HCOOH has increased year by year, and it is estimated that the global HCOOH market will grow to about 1 million tons by 2030. Compared with the current energy-intensive methanol carbonylation process for HCOOH production, the electrocatalytic reduction of CO2 for HCOOH production realizes the resource utilization of CO2 and the effective conversion of clean and low-grade electricity at the same time, so it is expected to become one of the large-scale utilization technologies of CO2.
Based on the above reasons, the electrocatalytic reduction of CO2 to HCOOH has attracted much attention in recent years. P-block metals (such as Sn, In, Bi) are favorable for the adsorption of formic acid to form intermediate * OCHO because of their unique oxyphilic characteristics, while their weak binding force with * H and high hydrogen evolution potential are favorable for the selective reduction of CO2 to HCOOH[10]. In this paper, the important research progress of p-block metal-based catalysts in the field of electrocatalytic reduction of CO2 to HCOOH is reviewed from the reaction mechanism (Table 1).Taking typical catalysts as examples, the strategies to improve the activity of CO2 reduction to HCOOH, such as oxide reduction conversion, doping, alloying and morphology control, were analyzed. Finally, the current challenges and future development directions in this field were summarized.

2 Formic acid formation mechanism

The catalytic reduction of CO2 on the electrode surface in aqueous electrolyte generally involves three steps: :CO2 chemisorption on the electrode surface, proton-coupled electron transfer to promote the cleavage of carbon-oxygen double bond, and product formation and desorption diffusion into the solution. The products produced in the actual catalytic process mainly depend on the physical and chemical properties of the catalyst itself or the adsorption ability of the catalyst for the reduction intermediates of CO2. In the CO2 reduction process, CO2 molecules are first adsorbed to the electrode surface and activated by single electron transfer to form radical anion *CO 2 · - (Formula 1), which is the rate-determining step of CO2 reduction. According to the binding mode of the intermediate *CO 2 · - to the catalyst surface, the subsequent reaction paths can be divided into two types (Fig. 2): (1) If the binding force between the C atom in *CO 2 · - and the surface is strong, the O atom is protonated to form * COOH,The intermediate further reacts with electrons and protons on the electrode surface to generate C1 or C2 products, and the type of the final products depends on the binding strength of the catalyst surface with intermediates such as * COOH, * CO, * H and * CHO; (2) If the O atom in the *CO 2 · - has a strong binding force with the catalyst surface, the C atom undergoes protonation to form * OCHO (Formula 2), followed by monatomic reduction to form formate HCOO- (Formula 3), which exists in the form of HCOOH (pH < 3.75) or HCOO-(pH>3.75) depending on the pH value of the electrolyte[10,13⇓~15]. In addition to the above mechanism, Bocarsly et al. Found that when SnO2 catalyzed the reduction of CO2, SnO2 was first reduced by 2e- to obtain tin (II) oxyhydroxide, which then reacted with CO2 to form surface-bonded tin-based carbonates (left column of Fig. 2)[16]. Finally, the adsorbed carbonate undergoes proton-coupled electron transfer (2e- and 1H+) to formate and complete desorption to HCOOH. Among many metal catalysts, some metal materials of ⅡB group (Cd, Hg), ⅢA group (In, Tl), ⅣA group (Sn, Pb) and ⅣA group (Bi) can effectively promote the protonation of C atom In the intermediate *CO 2 · - in the electroreduction process to form * OCHO due to their unique oxyphilicity, followed by further reduction to form HCOOH. In addition, these metals usually have high HCOOH selectivity because of their weak binding force with * H, high hydrogen evolution potential and limited reductive proton hydrogen production (HER) reaction[14,17⇓⇓ ~20]. Although Cd, Hg, Tl and Pb have high HCOOH activity and selectivity, the current research mainly focuses on the HCOOH activity improvement strategy of p-block metals (Sn, Bi, In)[19,21,22].
CO2 + * + e- → *CO 2 -
*CO 2 - + H+ → HCOO* 或 *CO 2 -+ H2O → HCOO* + OH-
HCOO* + e- → HCOO- + *

3 P-block metal-based electrocatalyst

3.1 Sn-based catalyst

In 1994, Hori et al. Found that when non-noble metal Sn electrode was used for electrocatalytic reduction of CO2, the maximum faradic efficiency of HCOOH formation could reach 88. 4%, but the high selectivity often only appeared in a higher overpotential range (η ~ 1 V), which seriously restricted the further development and practical application of Sn-based catalysts[23]. Therefore, improving the selectivity and activity of Sn-based catalysts (such as nano-Sn, SnOx, SnS2, Sn alloy, etc.) for HCOOH formation has become a hot research topic in this field. At present, the activity enhancement strategies of Sn-based catalysts mainly include: (1) increasing the number of active sites and improving the selectivity of HCOOH by adjusting the core parameters such as catalyst composition, morphology and structure; (2) adjust that electronic structure of the catalyst and optimizing the bon strength of the intermediate on the surface of the catalyst by means of doping, alloying, defect engineer and the like, thereby improving the kinetics of CO2 reduction reaction and improving the catalytic activity.
As a group Ⅳa metal element, Sn electrode exposed to air is easily oxidized to form a SnO or SnO2 layer with a certain thickness on the surface[24]. According to the Pourbaix diagram, the potential of electrocatalytic reduction of CO2 to HCOOH is more negative than the reduction potential of SnOx. Therefore, it is generally believed in early studies that although there is a layer of oxide on the surface of metal Sn electrode, elemental Sn is still the active center for catalyzing CO2 to HCOOH. However, the subsequent study found that the metal Sn electrode showed significant performance differences due to the different pretreatment methods[25⇓⇓~28]. Until 2012, Kanan et al. Systematically studied the effect of pretreatment methods on the catalytic performance of Sn electrode for CO2 to HCOOH, and found that when the metal Sn electrode contained a SnOx covering layer, its formic acid selectivity was significantly improved[29]; However, the Sn electrode, whose surface SnOx layer was removed by acidification treatment, had almost no CO2 reduction activity. They believe that although the SnOx layer will be reduced to elemental Sn during the electrocatalytic reduction process, there is still a small amount of O in the subsurface layer of the electrode. These sublayer O effectively promote the formation of the intermediate *CO 2 · - in the rate-determining step of CO2 reduction, thus improving the selectivity of CO2 reduction to HCOOH. Subsequently, Zhou et al. Used Sn nanoparticles (about 100 nm) as a model to study the effect of the thickness of the V vs Ag layer on the HCOOH selectivity, and found that when the thickness of the V vs Ag layer was 3.5 nm, the FEHCOOH reached the highest value of 64% (− 1.2 V vs Ag/AgCl), and further increasing the thickness of V vs Ag layer would lead to a decrease in HCOOH selectivity[30].
In view of the important role of surface SnOx layer and the diversity of synthesis methods of nano-SnO2 materials, most of the subsequent studies used SnO2 as catalyst precursor to obtain Sn electrode rich in sublayer O by electro-reduction method for CO2 reduction reaction[31⇓⇓~34]. For example, Zhang et al. Grew porous SnO2 nanosheets on carbon cloth by a high-temperature hydrothermal method (Figure 3A), and when the composite electrode was used for electrocatalytic reduction of CO2, it generated HCOOH with a current density as high as 45 mA·cm-2 (Figure 3B) and a selectivity of 87% (Figure 3C) at an overpotential of 880 mV[34]. The excellent catalytic performance benefits from the rough surface of 3D nanoporous materials, the large number of active sites provided by the high specific surface area and the co-promotion of sublayer O. In addition, when Spurgeon et al. Used porous SnO2 nanowires as catalyst precursors for electrocatalytic CO2, they found that during the reduction process, SnO2 nanowires would also produce abundant structural defects — grain boundaries[35]. Grain boundaries connect grains with different arrangement directions, and the atomic arrangement will transit from one direction to another, so the atomic arrangement at the grain boundary is irregular, often with higher energy, and easy to act as active sites, thus improving the catalytic activity. When used for V vs RHE reduction, the onset overpotential was only 350 mV, and the FEHCOOH was as high as 80% at -1.0 V vs RHE potential. Similar to SnO2, SnS2 was also used as a catalyst precursor, and after in situ reduction, the remaining sublayer S on the catalyst electrode surface could also promote the reduction of CO2 to formic acid[16,36].
In addition, it has been found that when Sn or SnO2 active components are loaded or confined on conductive substrates such as carbon nanotubes and graphene for electrocatalytic reduction of CO2 to HCOOH,It can not only increase the conductivity of the electrode and improve the dispersion of the active component, but also adjust the binding energy between the reaction intermediate and the electrode surface through the synergistic effect of the catalyst and the substrate, thereby improving the reaction performance[37⇓⇓⇓⇓~42]. For example, Meyer et al. Prepared graphene-supported nano SnO2 (∼ 5 nm) catalyst for CO2 electrochemical reduction[41]. At the − 1.8 vs SHE potential, the FEHCOOH was as high as 93%. Xie et al. Designed and synthesized graphene-confined ultrathin Sn nanosheets (thickness of 1.4 nm, Fig. 3D), and when they were used for electrocatalytic reduction of CO2, the catalytic current density was significantly higher than that of Sn nanoparticles (Fig. 3e),FEHCOOH up to 90% (Fig. 3F), and the reaction was maintained for at least 50 H without significant activity degradation[42]. They believed that the excellent performance of this kind of catalyst was due to the synergistic effect of Sn and graphene on the first electron transfer to form *CO 2 · - during the reduction of CO2. Ma et al. Synthesized octahedral SnO2 with exposed high-energy (332) and (111) facets, which exhibited high formate selectivity (> 80%) over a wide operating voltage range of 500 mV, with a maximum FEHCOOH of 95% and a formate partial current density of up to 500 mA·cm-2[43]. In situ Raman spectroscopy and DFT calculations show that the high-energy facets of SnO2 favor the adsorption of * OCHO and the desorption of HCOOH *, thus improving the selectivity of formate.
Although the catalytic active sites can be increased by catalyst structure design or morphology control, and then the catalytic activity can be increased. However, the range of regulation is directly limited by the properties of the electrode material itself[44]. Therefore, the key to improve the catalytic activity is to regulate the essential properties of the catalyst, such as electronegativity, adjust the electronic structure of the catalyst, and enhance the binding ability with the intermediate[45,46]. Heteroatom doping and alloying can adjust the electronic structure of metal electrode materials, such as band gap width, Fermi level, etc., and change the binding strength of intermediates on the catalyst surface, thus promoting the formation of CO2 target reduction products[47]. In recent years, heteroatom (such as N, Cu, S, Bi, etc.) doped Sn-based oxide materials used for CO2 reduction have been widely reported[36,48⇓ ~50]. For example, An et al. Found that when Bi atoms were doped into the SnO2, the FEHCOOH was more than 93%, and the catalytic activity was stable for 30 H without significant degradation[48]. This is because the hybridization between the 6s and 6p orbital electrons of Bi and the 2p orbital electrons of O in SnO effectively improves the adsorption stability of SnO (001) to the intermediate * OCHO, thus promoting the formation of HCOOH.
Alloying, as another method to control the adsorption energy of catalysts and reaction intermediates, has also been reported in the literature[19,51⇓⇓⇓ ~55]. For example, Zheng et al. Synthesized Sn-Cu alloys with different ratios of Cu to Sn by adjusting the ratio of Cu to Sn precursor[53]. It is found that when the ratio of Cu to Sn is 1:3, the formic acid selectivity of Sn-Cu alloy is the highest, and the FEHCOOH can reach 95%. The results of DFT calculation show that Sn-Cu alloy can effectively reduce the energy barrier of HCOOH formation and increase the energy barrier of H2 and CO, thus improving the selectivity of HCOOH. Sun et al. Synthesized the PdxSn(x=0.25~4) alloy, and when used to catalyze the reduction of CO2, the overpotential of the PdxSn alloy for HCOOH production was only 260 mV,FEHCOOH up to nearly 100%, and the formation of CO and H2 was completely inhibited[19]. Jiao et al. Synthesized a core-shell catalyst with Ag-Sn bimetal as the core and an ultrathin SnOx(1.7 nm) layer as the shell for electrocatalytic CO2 reduction (Fig. 3G ~ 3I)[55]. It is found that when the proportion of Sn reaches 25 at%, the FEHCOOH of the Ag-Sn/SnOx electrode is up to 80%. This is attributed to the fact that the increase of Sn concentration in the composite expands the alloy lattice, effectively stabilizes the intermediate * OCHO, and promotes the formation of HCOOH. However, when the Sn ratio is higher than 25 at%, a thick SnO2 layer is formed on the surface of the catalyst, which hinders the effective transfer of electrons and thus inhibits the formation of HCOOH.

3.2 Bi-based catalyst

As a group Va metal element, Bi is adjacent to Sn in the periodic table and is also oxyphilic, which can promote the protonation of C atom in the intermediate *CO 2 · - to form * OCHO, thus improving the selectivity of HCOOH[56,57]. Compared with Sn, Bi is more abundant in the crust, which lays a foundation for the large-scale application of Bi. Although as early as 1995, Komatsu et al. Studied the performance of electrocatalytic reduction of CO2 by metal Bi electrode, it was not until 2016 that researchers began to pay attention to the performance of electrocatalytic reduction of CO2 to HCOOH by Bi-based catalyst in aqueous electrolyte[58]. In the electrocatalytic process, the oxide layer on the surface of Sn electrode can effectively promote the formation of the key intermediate *CO 2 · -, thereby improving the selectivity of CO2 reduction to HCOOH, while the role of the BixO oxide layer on the surface of Bi electrode in the electrocatalytic reduction of CO2 has been controversial. Bocarsly et al. Used in situ attenuated total reflection Fourier transform infrared spectroscopy (in situ ATR-IR) to analyze the surface composition change process of Bi-based electrode during the reduction of in situ ATR, and found that the surface oxide composition did not change during the catalytic process, and no metal-carbonate intermediate was detected[59]. Therefore, they suggested that the catalytic activity of Bi-based catalysts is independent of the surface oxide. However, recent studies have found that the lone pair of Bi3+ in the surface BixO layer can promote CO2 adsorption and activation[60]. The 6s and 6p of Bi hybridize with the 2p orbital of O to form a stereochemically active lone electron pair, which promotes the transfer of electrons to acidic adsorbates (such as CO2), thus activating the adsorbed species[61⇓~63]. Xia et al. Found that the Bi — O bond was beneficial to the adsorption and activation of CO2 on the surface of Bi2O3, and the rate-determining step of catalytic reduction of CO2 changed from the formation of *CO 2 · - radical by one-electron reduction to the protonation process of this radical[64].
Increasing the number of outer surface atoms, crystal edge sites, corner sites, grain boundaries, and the number of active sites by controlling the morphology and microstructure of the catalyst also plays a vital role in enhancing the crystal edge site reduction performance of Bi electrode. For example, Min et al. Prepared dendritic nanoporous Bi catalyst by multi-step electrodeposition method using Bi3+ as precursor[65]. Compared with the bulk material, the catalyst contains a large number of unsaturated coordination sites, which effectively promotes the adsorption of the intermediate * OCHO, thereby improving the activity (FEHCOOH>89%) of CO2 reduction to HCOOH. Lee et al. Prepared Bi nanosheets containing a large number of edge and corner sites by pulse electrodeposition. The edge and corner sites of the catalyst was close to 100%, and the catalytic stability was up to 10 H[66]. Jin et al. Prepared two-dimensional ultrathin Bi nanosheets by liquid-phase exfoliation method, which catalyzed the formation of HCOOH with a current density up to 16.5 mA·cm-2 and a faradaic efficiency FE of about 86%, which is much higher than the performance of bulk materials under the same conditions[67]. DFT calculation studies show that compared with the bulk material, the ultrathin Bi nanosheets contain a large number of edge sites, which promotes the adsorption of the intermediate * OCHO, thus improving the reduction activity.
Due to the low melting point and easy oxidation of Bi, there are still many challenges in the direct preparation of Bi-based catalysts. At present, Bi-based catalysts are prepared by in-situ reduction method using Bi oxides, sulfides, oxyhalides and other catalytic precursors. For example, Li et al. First synthesized BiOI nanosheets, and then obtained ultrathin Bi nanosheets with well-preserved morphology through an in situ reduction method (Figure 4A), which exhibited a FEHCOOH of more than 90% (Figure 4B) and a catalytic current density of up to 24 mA·cm-2 when used for electrocatalytic reduction of CO2[68]. This study not only prepared an efficient catalyst for the reduction of CO2 to HCOOH, but also provided a new method for the synthesis of Bi nanosheets from oxyhalides as catalytic precursors[68]. Sargent et al. Used BiOBr as precursor to prepare nano-Bi catalyst by the same reduction method[69]. In a flow-cell, the catalyst catalyzes the formation of formic acid at a current density exceeding the 200 mA·cm-2,FE by more than 90%. Recently, Li et al. Used Bi2O3 double-walled nanotubes as catalytic precursors to obtain Bi nanotubes by in situ electrochemical reduction[70]. It was found that the Bi nanotubes contained a large number of structural defects, which promoted the adsorption of * OCHO, thereby improving the activity of CO2 reduction to formic acid.
Compositing Bi-based nanomaterials with highly conductive materials is also an important means to improve the HCOOH selectivity of Bi-based electrodes. For example, Lou et al. Grown multiple channel carbon matrix nanosheets on the surface of multiple channel carbon matrix (MCCM) for electrocatalytic reduction of CO2, the FEHCOOH was up to 93. 8%, and the FE was higher than 90% in a wide voltage range (300 mV)[71]. The excellent performance is due to the fact that the :(1)Bi2O3 nanosheets contain a large number of active sites; (2) MCCM contains a large amount of pyridine N and pyrrole N, which can effectively promote CO2 adsorption and electron transfer; (3) The nano-array structure effectively reduces the contact resistance between the catalyst and the carrier and shortens the diffusion path of the electrolyte. Nam et al. Uniformly dispersed BiOx nanoparticles with a size of less than 10 nm on the surface of XC-72R by hydrothermal method (Fig. 4C)[72]. The FE of this catalyst all exceeded 93% over a wide voltage range of ∼ 400 mV (Figure 4D), and the catalytic current density was as high as 18 mA·cm-2.
Similar to the Sn alloy catalyst, the Bi alloy material also exhibits high HCOOH selectivity. For example, Hoffman et al. Studied the relationship between the catalytic performance of dendritic Cu-Bi alloy for CO2 reduction and the composition[73]. It is found that due to the lattice mismatch between Cu and Bi, the alloy contains a large number of defect sites, which promotes the adsorption of catalytic intermediates and enhances the catalytic activity. The performance test shows that the maximum FEHCOOH is more than 90% when the Bi content is 40 wt% – 60 wt%. Chen et al. Found that when metal Bi is alloyed with Sn, the p and d orbitals of Sn are converted at the Bi-Sn interface and separated from the Fermi level, so that the electron cloud density is transferred from the highly electronegative O to the p and d orbitals of Sn, thus increasing the adsorption force of the Bi-Sn alloy surface on the intermediate * OCHO, so the HCOOH generation efficiency is higher[74]. At the potential of -1.1 V, the FEHCOOH of Bi-Sn alloy is as high as 96%, and the formation rate of HCOOH is 0.74 mmol·h-1·cm-2 [74].

3.3 In-based catalyst

Similar to Sn and Bi, In is also an environmentally friendly metal, but its price is about 10 times that of Sn and Bi, which seriously limits its research and industrial application. The In electrode exposed to air is also susceptible to oxidation, forming a In2O3 film on the surface. Under the condition of electrocatalytic reduction of CO2, In2O3 will react with H2O to produce In(OH)3,It further reacts with dissolved CO2 to form a In-CO3 intermediate, and finally desorbs to form a HCOOH product. In contrast, the formic acid selectivity of In electrode with surface oxide layer removed by chemical etching is lower[75]. Therefore, In2O3 also plays a key role in catalyzing the reduction of CO2 to HCOOH. Subsequent studies have shown that the faradic efficiency can even be as high as 100% when In2O3 or In(OH)3 is selected as the catalyst precursor for the electrocatalytic reduction of CO2 to formic acid[76]. In addition, increasing the number of active sites or changing the reaction microenvironment through structural design is also an effective strategy to improve the performance of In-based catalysts[77⇓~79]. For example, Luo et al. Fabricated a 3D porous In electrode by electrodeposition on a Cu mesh substrate, which reduced CO2 to formic acid with a Faradaic efficiency of 90% and a formic acid production rate of up to 1.14 mmol·cm-2·h-1. The excellent performance of the electrode is attributed to: (1) the porous structure increases the specific surface area of the In electrode, thereby exposing more active sites; (2) The porous structure improves the catalytic microenvironment, increases the local pH value, and effectively inhibits the hydrogen evolution reaction[77]. Hou et al. Used a solution containing Cl- as an electrolyte to obtain a dendritic In electrode by electrodeposition, which reduced CO2 at − 0.86 V with a catalytic current density of 86% 5.8 mA·cm-2,FEHCOOH[80].

4 Conclusion and prospect

In This paper, based on the mechanism of electrocatalytic reduction of CO2 to HCOOH, the strategy of enhancing the activity of p-block oxophilic metal (Sn, Bi, In) based catalysts for HCOOH production was described.The core parameters such as composition, morphology and structure of the catalyst were regulated by doping, alloying and defect engineering, and the role of the type and number of active sites and the electronic structure of the catalyst in the formation and adsorption of key intermediates *CO 2 · - and * OCHO was emphasized.
Nowadays, a series of breakthroughs have been made in the application of p-block metal-based materials as electrocatalytic reduction of CO2 to HCOOH, and the selectivity, catalytic current density and catalytic stability of these catalysts are gradually improved. In order to realize the industrial application of this kind of catalyst, more accumulation is needed in the following aspects.
(1) Research on reaction mechanism. At present, most of the mechanism studies rely on DFT calculations, but the electrocatalytic reduction of CO2 in aqueous solution is a complex reaction process involving gas-liquid-solid three-phase interface, and it is difficult for theoretical models to fully fit the real reaction environment of this process.Therefore, it is necessary to continue to explore in situ characterization techniques to capture reaction intermediates, establish accurate structure-property relationships at the atomic scale, explain reaction mechanisms, and provide guidance for catalyst structure optimization.
(2) Directional design of catalytic active sites. At present, the structure-activity relationship of these catalysts is still unclear, for example, the specific mechanism of the effect of defect sites on catalytic selectivity is still unclear. Current research still relies on trial-and-error methods, and there is a lack of systematic structure-activity relationship to guide the design and development of efficient catalysts. In the future, the development of model catalyst preparation technology with high concentration of single active sites, combined with in situ characterization technology, to clarify the role of specific active sites in the catalytic structure on the performance, will be the premise of efficient HCOOH production catalyst design.
(3) Optimize the reaction microenvironment and increase the catalytic current density. The application of industrial level requires the current density to reach 200 mA·cm-2. At present, the electrocatalytic reduction of CO2 in aqueous electrolyte mostly uses KHCO3 as electrolyte, in which the solubility of CO2 is low, which limits the improvement of catalytic current. When KOH is used as electrolyte, it is easy to react with CO2 and can not directly contact with CO2. Therefore, the improvement of catalytic current by designing new reactors, screening suitable electrolytes or creating new structural catalysts will play an important role in the industrial application of this kind of catalyst in the future.

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]

Franco F, Rettenmaier C, Jeon H S, Roldan Cuenya B. Chem. Soc. Rev., 2020, 49(19): 6884.
[2]

Zhang S, Fan Q, Xia R, Meyer T J. Acc. Chem. Res., 2020, 53: 255.
[3]

Wu J H, Huang Y, Ye W, Li Y G. Adv. Sci., 2017, 4(11): 1700194.
[4]

Appel A M, Bercaw J E, Bocarsly A B, Dobbek H, DuBois D L, Dupuis M, Ferry J G, Fujita E, Hille R, Kenis P J A, Kerfeld C A, Morris R H, Peden C H F, Portis A R, Ragsdale S W, Rauchfuss T B, Reek J N H, Seefeldt L C, Thauer R K, Waldrop G L. Chem. Rev., 2013, 113(8): 6621.
[5]

Nielsen D U, Hu X M, Daasbjerg K, Skrydstrup T. Nat. Catal., 2018, 1(4): 244.
[6]

Wang W, Wang S P, Ma X B, Gong J L. Chem. Soc. Rev., 2011, 40(7): 3703.
[7]

Ross M B, de Luna P, Li Y F, Dinh C T, Kim D, Yang P D, Sargent E H. Nat. Catal., 2019, 2(8): 648.
[8]

Birdja Y Y, PÉrez-Gallent E, Figueiredo M C, Göttle A J, Calle-Vallejo F, Koper M T M. Nat. Energy, 2019, 4(9): 732.
[9]

Raciti D, Wang C. ACS Energy Lett., 2018, 3(7): 1545.
[10]

Han N, Ding P, He L, Li Y Y, Li Y G. Adv. Energy Mater., 2020, 10(11): 1902338.
[11]

Philips F M, Gruter M G J, Koper T M M, Schouten J P K. ACS Sustainable Chem. Eng., 2020, 8(41): 15430.
[12]

Nitopi S, Bertheussen E, Scott S B, Liu X Y, Engstfeld A K, Horch S, Seger B, Stephens I E L, Chan K R, Hahn C, Nørskov J K, Jaramillo T F, Chorkendorff I. Chem. Rev., 2019, 119(12): 7610.
[13]

Ye L, Ying Y R, Sun D R, Zhang Z Y, Fei L F, Wen Z H, Qiao J L, Huang H T. Angew. Chem. Int. Ed., 2020, 59(8): 3244.
[14]

Sun Z Y, Ma T, Tao H C, Fan Q, Han B X. Chem, 2017, 3(4): 560.
[15]

Yu F, Zhang L H. CIESC Journal, 2021, 72 (4): 1815.
[16]

(于丰收, 张鲁华. 化工学报, 2021, 72 (4): 1815.).
[17]

Baruch M F, Pander J E III, White J L, Bocarsly A B. ACS Catal., 2015, 5(5): 3148.
[18]

Yang Z N, Oropeza F E, Zhang K H L. APL Mater., 2020, 8(6): 060901.
[19]

Li Q, Fu J J, Zhu W L, Chen Z Z, Shen B, Wu L H, Xi Z, Wang T Y, Lu G, Zhu J J, Sun S H. J. Am. Chem. Soc., 2017, 139(12): 4290.
[20]

Bai X F, Chen W, Zhao C C, Li S G, Song Y F, Ge R P, Wei W, Sun Y H. Angew. Chem. Int. Ed., 2017, 56(40): 12219.
[21]

Zhao C C, Wang J L. Chem. Eng. J., 2016, 293: 161.
[22]

Wang S B, Guan B Y, Lou X W D. J. Am. Chem. Soc., 2018, 140(15): 5037.
[23]

Yang H, Han N, Deng J, Wu J H, Wang Y, Hu Y P, Ding P, Li Y F, Li Y G, Lu J. Adv. Energy Mater., 2018, 8(35): 1801536.
[24]

Hori Y, Wakebe H, Tsukamoto T, Koga O. Electrochimica Acta, 1994, 39(11/12): 1833.
[25]

Ding P, Zhao H, Li T, Luo Y, Fan G, Chen G, Gao S, Shi X, Lu S, Sun X. J. Mater. Chem. A, 2020, 8(42): 21947.
[26]

Hu H S, Gui L Q, Zhou W, Sun J, Xu J M, Wang Q, He B B, Zhao L. Electrochimica Acta, 2018, 285: 70.
[27]

Liu S Y, Pang F J, Zhang Q W, Guo R J, Wang Z F, Wang Y C, Zhang W Q, Ou J Z. Appl. Mater. Today, 2018, 13: 135.
[28]

An X W, Li S S, Yoshida A, Wang Z D, Hao X G, Abudula A, Guan G Q. ACS Sustainable Chem. Eng., 2019, 7(10): 9360.
[29]

Zhang R, Lv W X, Lei L X. Appl. Surf. Sci., 2015, 356: 24.
[30]

Chen Y H, Kanan M W. J. Am. Chem. Soc., 2012, 134(4): 1986.
[31]

Wu J J, Risalvato F G, Ma S G, Zhou X D. J. Mater. Chem. A, 2014, 2(6): 1647.
[32]

Han N, Wang Y Y, Deng J, Zhou J H, Wu Y L, Yang H, Ding P, Li Y G. J. Mater. Chem. A, 2019, 7(3): 1267.
[33]

Yang H, Huang Y, Deng J, Wu Y L, Han N, Zha C Y, Li L G, Li Y G. J. Energy Chem., 2019, 37: 93.
[34]

Chen Y Y, Vise A, Klein W E, Cetinbas F C, Myers D J, Smith W A, Deutsch T G, Neyerlin K C. ACS Energy Lett., 2020, 5(6): 1825.
[35]

Li F W, Chen L, Knowles G P, MacFarlane D R, Zhang J. Angew. Chem. Int. Ed., 2017, 56(2): 505.
[36]

Kumar B, Atla V, Brian J P, Kumari S, Nguyen T Q, Sunkara M, Spurgeon J M. Angew. Chem. Int. Ed., 2017, 56(13): 3645.
[37]

Zheng X L, de Luna P, García de Arquer F P, Zhang B, Becknell N, Ross M B, Li Y F, Banis M N, Li Y Z, Liu M, Voznyy O, Dinh C T, Zhuang T T, Stadler P, Cui Y, Du X W, Yang P D, Sargent E H. Joule, 2017, 1(4): 794.
[38]

Zhang Q, Zhang Y X, Mao J F, Liu J Y, Zhou Y, Guay D, Qiao J L. ChemSusChem, 2019, 12(7): 1443.
[39]

Wang X, Lv J, Zhang J X, Wang X L, Xue C Z, Bian G Q, Li D S, Wang Y, Wu T. Nanoscale, 2020, 12(2): 772.
[40]

Fu Y, Wang T, Zheng W, Lei C, Hou Y. ACS Appl. Mater. Interfaces, 2020, 12: 16178.
[41]

Li Q Q, Zhang X R, Zhou X D, Li Q Y, Wang H Q, Yi J, Liu Y Y, Zhang J J. J. CO2 Util., 2020, 37: 106.
[42]

Zhang S, Kang P, Meyer T J. J. Am. Chem. Soc., 2014, 136(5): 1734.
[43]

Lei F C, Liu W, Sun Y F, Xu J Q, Liu K T, Liang L, Yao T, Pan B C, Wei S Q, Xie Y. Nat. Commun., 2016, 7: 12697.
[44]

Liu H, Su Y Q, Kuang S Y, Hensen E J M, Zhang S, Ma X B. J. Mater. Chem. A, 2021, 9(12): 7848.
[45]

Seh Z W, Kibsgaard J, Dickens C F, Chorkendorff I, Nørskov J K, Jaramillo T F. Science, 2017, 355(6321): 4998.
[46]

Hong W T, Risch M, Stoerzinger K A, Grimaud A, Suntivich J, Shao-Horn Y. Energy Environ. Sci., 2015, 8(5): 1404.
[47]

Man I C, Su H Y, Calle-Vallejo F, Hansen H A, Martínez J I, Inoglu N G, Kitchin J, Jaramillo T F, Nørskov J K, Rossmeisl J. ChemCatChem, 2011, 3(7): 1159.
[48]

Egdell R G, Rebane J, Walker T J, Law D S L. Phys. Rev. B, 1999, 59(3): 1792.
[49]

An X W, Li S S, Yoshida A, Yu T, Wang Z D, Hao X G, Abudula A, Guan G Q. ACS Appl. Mater. Interfaces, 2019, 11(45): 42114.
[50]

Zhang Y F, Liu J J, Wei Z X, Liu Q H, Wang C Y, Ma J M. J. Energy Chem., 2019, 33: 22.
[51]

Wei Y J, Liu J, Cheng F Y, Chen J. J. Mater. Chem. A, 2019, 7(34): 19651.
[52]

Ju W B, Zeng J Q, Bejtka K, Ma H, Rentsch D, Castellino M, Sacco A, Pirri C F, Battaglia C. ACS Appl. Energy Mater., 2019, 2(1): 867.
[53]

Sarfraz S, Garcia-Esparza A T, Jedidi A, Cavallo L, Takanabe K. ACS Catal., 2016, 6(5): 2842.
[54]

Zheng X L, Ji Y F, Tang J, Wang J Y, Liu B F, Steinrück H G, Lim K, Li Y Z, Toney M F, Chan K R, Cui Y. Nat. Catal., 2021, 4(5): 55.
[55]

Choi Y W, Scholten F, Sinev I, Roldan Cuenya B. J. Am. Chem. Soc., 2019, 141(13): 5261.
[56]

Luc W, Collins C, Wang S W, Xin H L, He K, Kang Y J, Jiao F. J. Am. Chem. Soc., 2017, 139(5): 1885.
[57]

Zhang B, Cao S Y, Wu Y Z, Zhai P L, Li Z W, Zhang Y T, Fan Z Z, Wang C, Zhang X M, Hou J G, Sun L C. ChemElectroChem, 2021, 8(5): 880.
[58]

Wang Y T, Li Y H, Liu J Z, Dong C X, Xiao C Q, Cheng L, Jiang H L, Jiang H, Li C Z. Angew. Chem. Int. Ed., 2021, 60(14): 7681.
[59]

Komatsu S, Yanagihara T, Hiraga Y, Tanaka M, Kunugi A. Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 1995, 63(3): 217.
[60]

Pander J E III, Baruch M F, Bocarsly A B. ACS Catal., 2016, 6(11): 7824.
[61]

Nolan M. ACS Omega, 2018, 3(10): 13117.
[62]

Oh W, Rhee C K, Han J W, Shong B. J. Phys. Chem. C, 2018, 122(40): 23084.
[63]

Walsh A, Payne D J, Egdell R G, Watson G W. Chem. Soc. Rev., 2011, 40(9): 4455.
[64]

Walker R J, Pougin A, Oropeza F E, Villar-Garcia I J, Ryan M P, Strunk J, Payne D J. Chem. Mater., 2016, 28(1): 90.
[65]

Deng P L, Wang H M, Qi R J, Zhu J X, Chen S H, Yang F, Zhou L, Qi K, Liu H F, Xia B Y. ACS Catal., 2020, 10(1): 743.
[66]

Koh J H, Won D H, Eom T, Kim N K, Jung K D, Kim H, Hwang Y J, Min B K. ACS Catal., 2017, 7(8): 5071.
[67]

Kim S, Dong W J, Gim S, Sohn W, Park J Y, Yoo C J, Jang H W, Lee J L. Nano Energy, 2017, 39: 44.
[68]

Zhang W J, Hu Y, Ma L B, Zhu G Y, Zhao P Y, Xue X L, Chen R P, Yang S Y, Ma J, Liu J, Jin Z. Nano Energy, 2018, 53: 808.
[69]

Han N, Wang Y, Yang H, Deng J, Wu J H, Li Y F, Li Y G. Nat. Commun., 2018, 9: 1320.
[70]

García de Arquer F P, Bushuyev O S, de Luna P, Dinh C T, Seifitokaldani A, Saidaminov M I, Tan C S, Quan L N, Proppe A, Kibria M G, Kelley S O, Sinton D, Sargent E H. Adv. Mater., 2018, 30(38): 1802858.
[71]

Gong Q, Ding P, Xu M, Zhu X, Li Y. Nat. Commun., 2019, 10: 2807.
[72]

Liu S B, Lu X F, Xiao J, Wang X, Lou X W D. Angew. Chem. Int. Ed., 2019, 58(39): 13828.
[73]

Lee C W, Hong J S, Yang K D, Jin K, Lee J H, Ahn H Y, Seo H, Sung N E, Nam K T. ACS Catal., 2018, 8(2): 931.
[74]

Hoffman Z B, Gray T S, Xu Y, Lin Q Y, Gunnoe T B, Zangari G. ChemSusChem, 2019, 12(1): 231.
[75]

Wen G B, Lee D U, Ren B H, Hassan F M, Jiang G P, Cano Z P, Gostick J, Croiset E, Bai Z Y, Yang L, Chen Z W. Adv. Energy Mater., 2018, 8(31): 1870138.
[76]

Detweiler Z M, White J L, Bernasek S L, Bocarsly A B. Langmuir, 2014, 30(25): 7593.
[77]

White J L, Bocarsly A B. J. Electrochem. Soc., 2016, 163(6): 410.
[78]

Luo W, Xie W, Li M, Zhang J, Züttel A. J. Mater. Chem. A, 2019, 7(9): 4505.
[79]

Ding C M, Li A L, Lu S M, Zhang H F, Li C. ACS Catal., 2016, 6(10): 6438.
[80]

Chu S L, Hong S, Masa J, Li X, Sun Z Y. Chem. Commun., 2019, 55(82): 12380.
[81]

Xia Z, Freeman M, Zhang D X, Yang B, Lei L C, Li Z J, Hou Y. ChemElectroChem, 2018, 5(2): 253.

Funding

National Natural Science Foundation of China(21905073)

National Natural Science Foundation of China(22008048)

Hundred Talents Project of Hebei Province(E2019050015)

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