Metal organic frameworks (MOFs) are very popular materials and have been largely researched in recent years. They have extremely wide ranges of applications in catalysis because of their variety of excellent properties. However, the research of MOFs themselves as catalysts is limited, the regularly porous structure and large surface area of MOFs can provide a natural physical space for loading highly dispersed metal nanocatalyst, which prevents the aggregation and leaching of metal nanoparticals. This has also been the major research direction of MOF catalysts in the last few years. This review reports the preparation methods of loading metal nanoparticles on MOFs to form bi- and multi-metallic catalysts and their applications in catalysis. The preparation methods,such as one pot synthesis, adsorption-reduction method, metal organic chemical vapor deposition method and solid grinding method are highlighted, and their applications in oxidation (the oxidation of alcohols, alkanes, alkenes and CO), hydrogenation (the hydrogenation of carbonyl compounds and olefinic compounds), Knoevenagel condensation and photocatalytic reaction (photocatalytic degradation of organic compounds and light-driven water splitting to produce hydrogen) are discussed in detail. In addition,the existing problems and the development prospects of such bi- and multi-metallic catalysts are also addressed in this review.

Contents
1 Introduction
2 The preparation methods of bi- or multi-metallic catalyst
2.1 One pot synthesis
2.2 Adsorption-reduction method
2.3 Metal organic chemical vapor deposition
2.4 Solid Grinding
2.5 Other methods
3 The applications of bimetallic or multi-metal catalyst
3.1 Oxidation reaction
3.2 Hydrogenation reaction
3.3 Knoevenagel condensation
3.4 Photocatalytic reaction
4 Conclusion and outlook