With the rapid growth of population and industrial activities， ammonia nitrogen has become a major indicator of water pollution， and its continuous increase in discharge has significantly contributed to eutrophication and ecological imbalance in aquatic environments. Therefore， the efficient removal of ammonia nitrogen from wastewater is of great environmental and practical importance. Among various treatment technologies， electrocatalytic oxidation has attracted extensive attention due to its high efficiency， low energy consumption， good controllability， and minimal secondary pollution. In this review， conventional biological， physical， and chemical methods are systematically compared， and their respective advantages and limitations are discussed. The fundamental principles of electrocatalytic oxidation are then summarized， including both direct oxidation pathways and indirect oxidation processes mediated by reactive species. The reaction mechanisms on different electrode materials are further analyzed， with particular emphasis on NH_x dehydrogenation pathways on noble and transition metal electrodes. In addition， indirect oxidation involving active chlorine species and hydroxyl radicals on metal oxide electrodes is discussed in detail. The role of non-metal electrodes in generating high-potential hydroxyl radicals and their contribution to ammonia nitrogen degradation are also highlighted. Recent advances in Pt-based catalysts， transition metal oxides， and non-metal electrodes are reviewed， focusing on strategies for improving catalytic activity， stability， and resistance to poisoning. Finally， key approaches such as surface engineering， alloy design， electronic structure regulation， and composite material construction are summarized， providing insights for the development of high-performance electrocatalysts and the future advancement of ammonia nitrogen wastewater treatment technologies.

Contents

1 Introduction

1.1 Current status of wastewater discharge

1.2 Types and hazards of ammonia nitrogen

1.3 Ammonia nitrogen wastewater treatment methods

2 Principles of electrocatalytic ammonia oxidation

2.1 Direct oxidation

2.2 Indirect oxidation

2.3 Principles of electrocatalytic ammonia oxidation

3 Research progress in electrode materials

3.1 Pt-based electrodes and derivatives

3.2 Metal and metal-based electrodes

3.3 Non-metallic and derivative electrodes

4 Conclusion