{"title":"Efficient Electrochemical Nitrate Reduction to Ammonia Driven by a Few Nanometer-Confined Built-In Electric Field","authors":"Maolin Zhang, Zedong Zhang, Shaolong Zhang, Zechao Zhuang, Kepeng Song*, Karthik Paramaiah, Moyu Yi, Hao Huang* and Dingsheng Wang, ","doi":"10.1021/acscatal.4c02317","DOIUrl":null,"url":null,"abstract":"<p >Converting nitrate (NO<sub>3</sub><sup>–</sup>) to ammonia (NH<sub>3</sub>) through the electrochemical reduction method offers an appealing approach for wastewater treatment and facilitates nitrogen cycling in nature. However, this electrolytic method involves a series of proton-coupled electron transfer processes and comes with severe competing reactions. Consequently, there is a significant demand for catalysts exhibiting good catalytic activities and selectivities. Here, a series of copper–cobalt binary sulfide nanosheets with varying Cu/Co compositions were prepared to investigate the synergy effects between the components copper sulfide and cobalt sulfide on their catalytic performance. As a result, a volcano-like correlation between the Cu/Co ratio and electrocatalytic performance was built. The optimal catalyst Cu<sub><i>x</i></sub>S–Co<sub>0.5</sub> exhibited a maximum Faradaic efficiency (FE) of ∼95.6% for ammonia at −1.4 V vs Ag/AgCl. The highest ammonia yield rate of 5.36 mg/h·cm<sup>2</sup> was achieved at −1.6 V vs Ag/AgCl, which was 6.5- and 3.8-fold relative to those of pure Cu<sub><i>x</i></sub>S and CoS<sub>2</sub>, respectively. By combining spectroscopy characterizations with theoretical calculations, we revealed that catalyst Cu<sub><i>x</i></sub>S–Co<sub>0.5</sub> with a built-in electric field confined to a few nanometers played a critical role in enhancing electron transfer and creating more active sites. Besides, its improved water dissociation capability was essential for the hydrogenation of reduction intermediates, collectively contributing to the enhanced catalytic performance.</p>","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":11.3000,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acscatal.4c02317","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Converting nitrate (NO3–) to ammonia (NH3) through the electrochemical reduction method offers an appealing approach for wastewater treatment and facilitates nitrogen cycling in nature. However, this electrolytic method involves a series of proton-coupled electron transfer processes and comes with severe competing reactions. Consequently, there is a significant demand for catalysts exhibiting good catalytic activities and selectivities. Here, a series of copper–cobalt binary sulfide nanosheets with varying Cu/Co compositions were prepared to investigate the synergy effects between the components copper sulfide and cobalt sulfide on their catalytic performance. As a result, a volcano-like correlation between the Cu/Co ratio and electrocatalytic performance was built. The optimal catalyst CuxS–Co0.5 exhibited a maximum Faradaic efficiency (FE) of ∼95.6% for ammonia at −1.4 V vs Ag/AgCl. The highest ammonia yield rate of 5.36 mg/h·cm2 was achieved at −1.6 V vs Ag/AgCl, which was 6.5- and 3.8-fold relative to those of pure CuxS and CoS2, respectively. By combining spectroscopy characterizations with theoretical calculations, we revealed that catalyst CuxS–Co0.5 with a built-in electric field confined to a few nanometers played a critical role in enhancing electron transfer and creating more active sites. Besides, its improved water dissociation capability was essential for the hydrogenation of reduction intermediates, collectively contributing to the enhanced catalytic performance.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.