Revealing the activity origin of ultrathin nickel metal–organic framework nanosheet catalysts for selective electrochemical nitrate reduction to ammonia: Experimental and density functional theory investigations
Revealing the activity origin of ultrathin nickel metal–organic framework nanosheet catalysts for selective electrochemical nitrate reduction to ammonia: Experimental and density functional theory investigations
复制标题
揭示超薄镍金属有机骨架纳米片催化剂选择性电化学硝酸盐还原成氨的活性起源：实验和密度泛函理论研究
DOI：
10.1016/j.jcis.2023.01.121
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发表时间：
2023
影响因子：
9.9
通讯作者：
Chuanyi Wang
中科院分区：
文献类型：
--
作者：
Fan Pan;Jianjun Zhou;Tian Wang;Yunqing Zhu;Hongrui Ma;Junfeng Niu;Chuanyi Wang
电化学硝酸盐还原反应（NitRR）为硝酸盐还原和氨合成提供了一条可持续的途径，但仍存在硝酸盐转化率低、氨选择性低、反应动力学缓慢等问题。明确的结构-性能关系对于设计高效催化剂和理解反应机理至关重要。本文采用一步溶剂热法制备了以泡沫镍为载体的镍-金属有机骨架（Ni-MOF）纳米片，该纳米片具有良好的稳定结构、大的电化学活性表面积和低的电子传输电阻。在-1.4 V下，硝酸盐还原率、速率常数、氨选择性和产率分别达到96.4%、0.448 h-1、80%和110.13 ug·h-1·cm-2。实验和理论研究表明，羟基连接的镍原子表现出更高的硝酸盐吸附性能和更低的活化能对NitRR相比，羧酸连接的镍原子。机理研究揭示了一个硝酸盐到氨的反应途径，涉及多个中间物种的Ni-MOF纳米片催化剂。本工作为构建高效电催化剂将硝酸盐选择性转化为有价值的氨提供了新的途径。
The electrochemical nitrate reduction reaction (NitRR) affords a sustainable way for nitrate mitigation and ammonia synthesis, but there are still some problems such as poor nitrate conversion, low ammonia selectivity, and slow reaction kinetics. A clear structure-performance relationship is essential for designing efficient catalysts and understanding the reaction mechanisms. Herein, ultrathin nickel metal–organic framework (Ni-MOF) nanosheets supported on Ni foam featuring a well-defined stable structure, large electrochemically active surface area, and low electron transport resistance were prepared by a one-step solvothermal process. At −1.4 V, the nitrate reduction, rate constant, ammonia selectivity, and yield reached 96.4%, 0.448 h−1, 80%, and 110.13 ug·h−1·cm−2, respectively. Experimental and theoretical studies demonstrated that the hydroxyl-ligated Ni atoms exhibited higher nitrate adsorption properties and lower activation energy towards NitRR compared to carboxylic acid-ligated Ni atoms. Mechanism investigations revealed a nitrate-to-ammonia reaction pathway involving multiple intermediate species on Ni-MOF nanosheet catalysts. This work offers a new avenue to construct highly efficient electrocatalysts for the selective transformation of nitrate to valuable ammonia.