2D materials design and property modulation for electrocatalytic nitrate reduction to ammonia

Abstract Currently, ammonia is an important chemical in modern society, widely used in agriculture and energy-conversion fields. However, there are existing energy-consumption and environmental problems in the traditional process of ammonia synthesis. At present, electrochemical nitrate reduction reaction (NO₃ ⁻RR) uses renewable electricity as power to achieve simultaneous nitrate removal and ammonia generation, providing an efficient, green and clean platform for sustainable ammonia synthesis. As an ideal model material for electrochemistry research, two-dimensional (2D) materials with tunable surface properties and electronic structure have aroused immense interest in electrocatalysis applications. The atomic-layer structure of 2D materials can significantly affect their physical/chemical properties, while size and surface characteristics are important aspects to be considered for designing and synthesizing efficient catalysts to achieve the high performance of the electrocatalytic NO₃ ⁻RR application. In this review, we discuss the fundamentals of electrocatalytic nitrate reduction to ammonia including reaction mechanisms and basic research methods. Moreover, synthetic methods and design strategies of 2D-material electrocatalysts are introduced and specific applications of 2D material in electrocatalytic NO₃ ⁻RR are demonstrated. Furthermore, future perspectives are proposed to inspire novel attempts for new 2D materials applications across broad fields.