当前位置:科学网首页 > 小柯机器人 >详情
电催化析氧中Co掺杂和Cr空位协同优化镍铁双位点原子环境
作者:小柯机器人 发布时间:2025/1/10 17:22:28

北京航空航天大学郭林团队报道了电催化析氧中Co掺杂和Cr空位协同优化镍铁双位点原子环境。相关研究成果于2025年1月8日发表在《美国化学会杂志》。

NiFeOOH的双位协同催化机制表明,Ni位的弱吸附和Fe位的强吸附限制了其对碱性析氧反应(OER)的活性。大规模密度泛函理论(DFT)计算证实,Co掺杂可以增加Ni的吸附,而金属空位可以减少Fe的吸附。这两个因素的结合可以进一步调节原子环境,优化含氧中间体的自由能,从而增强OER活性。

因此,研究人员使用Co掺杂和Cr空位制备了VCr、Co-NiFeOOH的非晶催化剂。它在100 mA cm-2时具有239 mV的OER过电位,在500 mA cm-2下具有500小时的高稳定性,电位保持率为~98%。基于阴离子交换膜(AEM)的水电解槽在1 M KOH中1.68 V下表现出1A cm–2的显著性能。

XPS、软XAS和XANES结合Bader电荷分析结果表明,局部微环境的调节可以通过Co掺杂增加Ni的价态,从而提高Ni位点的吸附能。Cr空位可以缓解Fe位点的强吸附。DFT计算证实,Co掺杂和Cr空位的协同效应可以重新分配Ni/Fe位点上的电荷,优化Ni和Fe的d带中心,并赋予催化剂Ni-Fe双位点,以降低OER速率决定步骤的能量势垒。

附:英文原文

Title: Synergistic Atomic Environment Optimization of Nickel–Iron Dual Sites by Co Doping and Cr Vacancy for Electrocatalytic Oxygen Evolution

Author: Hua-Jie Niu, Nian Ran, Wei Zhou, Weixuan An, Chuanxue Huang, Wenxing Chen, Min Zhou, Wen-Feng Lin, Jianjun Liu, Lin Guo

Issue&Volume: January 8, 2025

Abstract: The dual-site synergistic catalytic mechanism on NiFeOOH suggests weak adsorption of Ni sites and strong adsorption of Fe sites limited its activity toward alkaline oxygen evolution reaction (OER). Large-scale density functional theory (DFT) calculations confirm that Co doping can increase Ni adsorption, while the metal vacancy can reduce Fe adsorption. The combined two factors can further modulate the atomic environment and optimize the free energy toward oxygen-containing intermediates,  thus enhancing the OER activity. Accordingly, we used Co doping and Cr vacancies to fabricate an amorphous catalyst of VCr,Co-NiFeOOH. It provides an OER overpotential of 239 mV at 100 mA cm–2 and high stability over 500 h at 500 mA cm–2 with a ~98% potential retention. The resulting water electrolyzer based on an anion exchange membrane (AEM) exhibits  a remarkable performance of 1 A cm–2 at 1.68 V in 1 M KOH. XPS, soft-XAS, and XANES combined with Bader charge analysis results reveal that the regulation of the local microenvironment can increase the valence state of Ni by Co doping, thus improving the adsorption energy on Ni sites. The Cr vacancy can alleviate the strong adsorption on Fe sites. DFT calculations confirm that the synergistic effect of Co doping and Cr vacancies can redistribute the charge on the Ni/Fe sites, optimize the d-band center of Ni and Fe, and endow the catalyst with Ni–Fe dual sites to reduce the energy barrier of the OER rate-determining step.

DOI: 10.1021/jacs.4c14675

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c14675

期刊信息

JACS:《美国化学会志》,创刊于1879年。隶属于美国化学会,最新IF:16.383
官方网址:https://pubs.acs.org/journal/jacsat
投稿链接:https://acsparagonplus.acs.org/psweb/loginForm?code=1000


Baidu
map