Fu Gaoliang, Li Weiwei, Zhang Jia-Ye, Li Mengsha, Li Changjian, Li Ning, He Qian, Xi Shibo, Qi Dongchen, MacManus-Driscoll Judith L, Cheng Jun, Zhang Kelvin Hongliang
State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P.R. China.
Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.
Small. 2021 Mar;17(12):e2006930. doi: 10.1002/smll.202006930. Epub 2021 Mar 3.
Aliovalent doping is widely adopted to tune the electronic structure of transition-metal oxides for design of low-cost, active electrocatalysts. Here, using single-crystalline thin films as model electrocatalysts, the structure-activity relationship of Fe states doping in perovskite LaNiO for oxygen evolution reaction (OER) is studied. Fe state is found to be crucial for enhancing the OER activity of LaNiO , dramatically increasing the activity by six times, while Fe has negligible effect. Spectroscopic studies and DFT calculations indicate Fe states enhance the degree of Ni/Fe 3d and O 2p hybridization, and meanwhile produce down-shift of the unoccupied density of states towards lower energies. Such electronic features reduce the energy barrier for interfacial electron transfer for water oxidization by 0.2 eV. Further theoretical calculations and H/D isotope experiments reveal the electronic states associated with Fe -O -Ni configuration accelerate the deprotonation of *OH to *O (rate-determining step), and thus facilitate fast OER kinetics.
异价掺杂被广泛用于调节过渡金属氧化物的电子结构，以设计低成本、活性高的电催化剂。在此，以单晶薄膜作为模型电催化剂，研究了钙钛矿型LaNiO₃中Fe态掺杂对析氧反应（OER）的结构-活性关系。发现Fe态对于提高LaNiO₃的OER活性至关重要，可使活性显著提高六倍，而Fe的影响可忽略不计。光谱研究和密度泛函理论（DFT）计算表明，Fe态增强了Ni/Fe 3d和O 2p的杂化程度，同时使未占据态密度向更低能量方向下移。这种电子特性使水氧化界面电子转移的能垒降低了0.2 eV。进一步的理论计算和H/D同位素实验表明，与Fe -O -Ni构型相关的电子态加速了OH向O的去质子化（速率决定步骤），从而促进了快速的OER动力学。
