4d Metal-doped liquid Ga for efficient ammonia electrosynthesis at wide N_(2) concentrations  

4d金属掺杂液态Ga用于宽N_(2)浓度下的高效氨电合成

作　　者：Yingying Wei Yuyao Sun Yaodong Yu Yue Shi Zhe Wu Lei Wang Jianping Lai 魏莹莹;孙昱垚;于耀东;石月;吴哲;王磊;赖建平(青岛科技大学化学与分子工程学院,生态化工国家重点实验室基地,生态化学工程与绿色制造国际科技合作基地,山东青岛266042)

机构地区：[1]State Key Laboratory Base of Eco-Chemical Engineering,International Science and Technology Cooperation Base of Eco-chemical Engineering and Green Manufacturing,College of Chemistry and Molecular Engineering,Qingdao University of Science and Technology,Qingdao 266042,Shandong,China

出　　处：《Chinese Journal of Catalysis》2024年第12期194-203,共10页催化学报(英文)

基　　金：国家自然科学基金(52272222);泰山学者青年专家计划(tsqn201909114,tsqn201909123);山东省高校青年创新团队(202201010318).

摘　　要：Electrocatalytic nitrogen reduction reaction under ambient conditions is a promising pathway for ammonia synthesis.Currently nitrogen reduction reactions are carried out in N_(2)-saturated environments and use high-purity nitrogen as feedstock,which is costly.Here,we prepared carbon-coated ultra-low 4d metal Ru-doped liquid metal Ga(Ru_(0.06)/LM@C)for NRR over a wide range of N_(2) concentrations.Comprehensive analyses show that the introduction of the ultra-low 4d element Ru can effectively adjust the electronic structure through orbital interactions,thus enhancing the adsorption of nitrogen-containing intermediates.The liquid catalyst utilized its mobility to provide a higher density of active sites.In addition,the material Ru_(0.06)/Ga@C itself has the ability to promote product desorption.The three act synergistically to optimize the N_(2) mass transfer path,thereby increasing the*NNH coverage and further improving the ammonia yield over a wide range of N_(2) concentrations.The maximum NH_(3) yield of the catalyst can reach 126.0μg h^(-1) mgcat^(-1)(at–0.3 V vs.RHE)with high purity N_(2) as feed gas,and the Faraday efficiency is 60.4%at–0.1 V vs.RHE.Over a wide range of N_(2) concentrations,the NH_(3) yield of the catalyst was greater than 100μg h^(-1) mgcat^(-1) with a Faraday efficiency higher than 47%.The catalytic performance is much higher than that of solid Ga@C and reported p-block metal-based catalysts.工业使用的氨主要采用Haber-Bosch工艺生产,该过程耗能巨大,且每年工业生产氨会排放约4.2亿吨二氧化碳,与当前低碳环保理念不符.电催化氮还原反应(eNRR)是一种很有前途的氨合成途径,该反应由太阳能或可再生能源提供电能,在常温常压下进行.然而,目前研究的eNRR都是在N_(2)饱和的环境中进行的,并且使用高纯度的N_(2)作为原料,成本较高.因此,设计和开发适用于大范围N_(2)浓度的高效电催化eNRR催化剂是非常有吸引力和挑战性的.p嵌段金属由于其高丰度和低成本被广泛研究用于eNRR.更重要的是,p嵌段金属占据的p轨道给N_(2)未占据的反键轨道提供电子,从而有效地削弱N≡N.许多关于p嵌段金属基电催化剂的设计和调控及其性能改进策略的研究已经被报道.虽然有报道称3d元素的掺杂可以在一定程度上降低加氢过程的能垒,但所报道的催化剂中间体吸附能力较弱,产物脱附困难,影响了催化性能.因此,相似的吸附能导致增强了中间体吸附和促进产物脱附之间的内在矛盾,这反过来又阻碍了p嵌段金属基催化剂实现高效合成氨.结合最近的研究,与3d元素相比,4d元素能够通过轨道间相互作用有效地调节电子结构.本文引入了一种协同策略,通过将超低含量的4d元素Ru加入液态金属Ga中,来调节Ga的电子结构和促进活性位点的持续暴露.该策略为解决关键中间体覆盖率低和产物解吸困难的问题提供了新的思路,并在较宽的N_(2)浓度下实现了高效的eNRR.优化后的催化剂以高纯N_(2)为原料气时,在‒0.3 V vs.RHE的过电位下实现了高达126.0μg h^(-1) mgcat^(-1)的氨产率,在‒0.1 V vs.RHE下法拉第效率高达60.4%.在较低N_(2)浓度时,该催化剂的氨产率均大于100μg^(-1) mgcat^(-1),法拉第效率高于47%.此外,为了研究Ru0.06/LM@C催化剂在eNRR中的实际应用潜力,制备了气体扩散电极来提高气体对电化学界面的可及性,�

关 键 词：Liquid catalyst ELECTROCATALYSIS Nitrogen reduction reaction Ammonia synthesis ELECTROCATALYST 

分 类 号：O64[理学—物理化学]