Proximity electronic effect of adjacent Ni Site enhances compatibility of hydrogenation and deoxygenation over Cu Site to boost nitrate electroreduction to ammonia  

相邻Ni位点近邻电子效应增强Cu位点加氢和脱氧匹配度促进硝酸盐电还原产氨

作　　者：Xue-Feng Cheng Qing Liu Qi-Meng Sun Huilong Dong Dong-Yun Chen Ying Zheng Qing-Feng Xu Jian-Mei Lu 成雪峰;刘青;孙启孟;董慧龙;陈冬赟;郑莹;徐庆锋;路建美(苏州大学材料与化学化工学部,江苏苏州215123;淮阴师范学院化学化工学院,江苏淮安223300;西安大略大学化学与生化工程系,加拿大西安大略伦敦;常熟理工学院材料工程学院,江苏常熟215500)

机构地区：[1]College of Chemistry,Chemical Engineering and Materials Science,Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow University,Suzhou 215123,Jiangsu,China [2]School of Chemistry and Chemical Engineering,Huaiyin Normal University,Huai'an 223300,Jiangsu,China [3]Department of Chemical and Biochemical Engineering,Western University,London N6A37K,Ontario,Canada [4]School of Materials Engineering,Changshu Institute of Technology,Changshu 215500,Jiangsu,China

出　　处：《Chinese Journal of Catalysis》2025年第3期285-298,共14页催化学报(英文)

基　　金：国家自然科学基金(21938006,21776190,51773144);江苏省基础研究计划重点项目(BK20202012);中国博士后科学基金会面上项目(2020M681714);江苏省高等学校优势学科建设工程资助项目(PAPD);科技部智能纳米环保新材料与检测技术国际联合研究中心项目(SDGH_(2)303).

摘　　要：Electrocatalytic conversion of nitrate to ammonia(NITRR)can simultaneously achieve the removal of nitrate and the synthesis of value-added ammonia,a promising candidate to replace Haber-Bosch process with low carbon dioxide emissions.However,high hydrogenation energy barrier for*NO intermediates and insufficient supply of active hydrogen cause slow hydrogenation process,and further result in low efficiency of nitrate conversion and ammonia synthesis.Herein,a series of tandem catalysts,one-dimensional coordination polymers(1D CCPs)with dual sites are synthesized and obtained 190.4 mg h^(-1)mgcat^(-1)ammonia production rate with Faradaic efficiency of 97.16%,outperforming to the most of recent reported catalysts.The catalytic performances are well-maintained even after a long-term stability test of 1200 h,laying the foundation for practical applications.Density functional theory results reveal that the stationary adsorbed*NO on Ni site induced proximity electronic effect could reduce the energy barrier for hydrogenation of*NO intermediates over Cu site.In addition,the Ni site in the dual sites 1D CCPs is conducive to generating active hydrogen,providing rich proton source to boost the hydrogenation of*NO,and further enhancing the compatibility of deoxygenation and hydrogenation process.Our work paves a new insight into the mechanism of NITRR process and will inspire more research interests in exploring the proximity electronic effect in catalytic process.电催化硝酸盐还原产氨(NITRR)可以同时实现硝酸盐的去除和高附加值氨的合成,有望替代Haber-Bosch工艺,实现低二氧化碳排放制氨的新工艺.NITRR的过程可分为脱氧和加氢两个过程,其中脱氧进程速率较快,而加氢进程由于存在较高的能垒导致效率较低.从而造成脱氧与加氢过程速率不匹配的问题,进而导致硝酸盐还原产氨的效率较低.因此,通过催化剂结构的合理设计,加快加氢反应进程,提升脱氧与加氢进程的匹配程度,是实现NITRR整体效率提升的有效方法.本文通过调整铜盐的投料比,使用水热法合成了七种不同的一维金属配位聚合物链材料(1D CCPs).其中,Ni_(1)Cu_(1)-BTA材料展现出最佳的硝酸盐还原产氨性能,在-0.8 V电压下实现了高达190.4 mg h^(-1)mg_(cat)^(-1)的产氨效率和高达97.16%的法拉第效率,优于大多数最近报道的NITRR催化剂.在1200 h的长期测试过程中,Ni_(1)Cu_(1)-BTA始终保持稳定的催化性能,并实现了克级氯化铵的回收.密度泛函理论计算表明,近邻电子效应诱导的~*NO中间体在Ni和Cu位点上的预吸附可以有效降低~*NO→~*NHO在邻近Cu或Ni位点上的能垒.尤其是硝酸盐在NiCu-BTA中Cu位点上转化成氨的决速步骤能垒降低到0.01 eV,极大地促进了NITRR的进程.同时,双位点1D CCPs中的Ni位点有利于产生活性氢,提供丰富的质子源以促进加氢过程,从而有效提高催化转化效率.此外,组装的Zn-NO_(3)^(-).电池实现了最高5.9 mW cm^(-2)的功率密度,在16 mA cm^(-2)的电流密度下放电时,氨产率为1.61 mg h^(-1)·cm^(-2),法拉第效率为95.36%.综上所述,近邻电子效应可以有效提升脱氧和加氢过程的速率匹配程度,从而提升NITRR的整体效率.本工作为NITRR过程背后的机制提供了新的见解,并将进一步激发对双位点催化剂在多步骤电催化反应中的研究兴趣.

关 键 词：ELECTROCATALYSIS Ammonia synthesis Nitrate reduction Proximity electronic effect Dual sites 

分 类 号：O643.36[理学—物理化学]