The damage caused by water pollution has seriously affected human health, in which nitrate is difficult to remove effectively because of its stability and solubility in the water environment. Among the various technologies for nitrate removal, electrocatalytic conversion of nitrate to ammonia is one of the best choice because of its green and efficient nature as well as its ability to “turn waste into treasure”. In recent years, the development of high-performance electrocatalysts to promote the activity of electrocatalytic nitrate reduction ( NO3RR) has received extensive attention from researchers. Among various electrocatalytic materials for NO3RR, carbon-based catalysts have become a promising electrocatalyst due to the advantages of affordable price, controllable structure, excellent stability and exceptional reactivity. Focusing on the carbon-based materials, this review summarizes the research progress of carbon-based catalysts for NO3RR in recent years, including heteroatom-doped carbon-based catalysts as well as metal and metal oxide-loaded or modified carbon-based catalysts. Opinions on the current challenges and future research directions of carbon-based catalysts for NO3RR are also presented. This review hopes to provide some references and principles for the design and preparation of carbon-based catalysts for high-performanceNO3RR process.

Compared with the traditional Haber Bosch process, green and pollution-free electrocatalytic nitrogen reduction (NRR) has received considerable attention in the electrocatalysis field in the last decade. To address the issue of its low reactivity as well as the existence of competitive reactions, efficient electrocatalysts are particularly important. In this paper, NiO nanomaterials were synthesized by a simple water bath reaction. The effect of different calcination temperatures on the structure of NiO catalyst and its catalytic activity was studied. Uniform NiO-600 nanoparticles (56 ± 9.3 nm) obtained at 600 ℃ showed the best electrocatalytic NRR activity with an NH3 yield of 12 μg h− 1 mg− 1 and a Faraday efficiency of 5.5% at -0.5V (vs.RHE). The small particle size of the nanoparticles provided more active sites and the oxygen-rich vacancies facilitated the adsorption and activation of N2, which improved the catalytic activity of NiO-600. This study highlights the need for calcination temperature regulation and the huge impact on catalyst structure.