【Ten Years of Rapid Development in Chemical Equipment】1747–2024: New Technology Using Sequential Catalysts to Improve the Efficiency of Ammonia Production via Nitrate Electroreduction

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Happy May Day 2024! Safety first. Let’s give praise and support to the achievements in China’s chemical engineering technology and equipment. **********************【Ten Years of Progress in Chemical Engineering Equipment】A continuously updated summary post – feel free to join the discussions: https://bbs.hcbbs.com/thread-3576046-1-1.html (Source: Haichuan Chemical Engineering Forum) ***************** New technology that significantly improves the efficiency of ammonia synthesis through nitrate electroreduction. On May 10th, reporters learned from the University of Science and Technology of China that Professor Ceng Jie and his research team have developed a tandem catalyst for the nitrate electroreduction process used in ammonia synthesis. By combining copper single-atom catalysts with cobalt tetraoxide nanosheets, they are able to regulate the adsorption energy of intermediates during nitrate electroreduction, thereby enhancing the efficiency of this process. The relevant findings were recently published in Nature Communications. Electrocatalytic reduction of nitrates in wastewater to ammonia is not only an effective method for wastewater treatment, but also a highly promising approach for the sustainable synthesis of ammonia. However, the electroreduction of nitrates involves the adsorption and transformation of various nitrogen-containing intermediates, and the diversity of adsorption configurations makes it difficult for a single catalyst to simultaneously achieve optimal adsorption of these intermediates. Although the copper-based catalysts widely reported today are beneficial for the adsorption of nitrates, one of the key problems faced by them is that the excessive accumulation of nitrites can lead to catalyst deactivation, which also hinders the subsequent hydrogenation step and limits further increases in ammonia yield. The researchers uniformly loaded cobalt oxide nanosheets on the surface of copper single-atom catalysts. Subsequent electrochemical tests showed that the ammonia production rate in the nitrate electroreduction reaction was increased by 2.2 times and 3.6 times, respectively, compared to those using the copper single-atom catalysts and cobalt oxide nanosheets alone. Combining electrochemical in-situ Raman spectroscopy and theoretical calculations, copper single atoms promoted the conversion of nitrates to nitrites, while adjacent cobalt oxide enhanced the adsorption of nitrites, thereby facilitating the sequential electroreduction of nitrates and nitrites and significantly increasing the ammonia production rate.