Ouyang Qi, Cheng Shichao, Yang Chunhui, Lei Zuotao
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin150001, People's Republic of China.
Inorg Chem. 2023 Jan 30;62(4):1719-1727. doi: 10.1021/acs.inorgchem.2c04174. Epub 2023 Jan 13.
Electrocatalytic water splitting is a feasible technology that can produce hydrogen from renewable sources. The oxygen evolution reaction (OER), which has a slower kinetics and higher overpotential than the hydrogen evolution reaction, is the bottleneck that limits the overall water splitting. It is essential to develop efficient OER catalysts to reduce the anode overpotential. Herein, Ni,Co,Yb-FeOOH nanorod arrays grown directly on a carbon cloth are synthesized by a simple one-step hydrothermal method. The doped Ni and Co can occupy Fe and Fe sites in FeOOH, increasing the concentration of oxygen vacancies (), and the doped Yb with a larger ionic radius can occupy the interstitial sites, which leads to more edge dislocations. and edge dislocations greatly enrich the active sites in FeOOH/CC. In addition, density functional theory calculations confirm that doping of Ni, Co, and Yb modulates the electronic structure of the main active Fe sites, bringing its d-band center closer to the Fermi level and reducing the Gibbs free energy change of the rate-determining step of the OER. When the current density reaches 10 mA cm, the overpotential of Ni,Co,Yb-FeOOH/CC is only 230.9 mV, and the Tafel slope is 22.7 mV dec. In particular, a mechanism of multi-cation doping synergistic interaction with the oxygen vacancy and edge dislocation to enhance the OER catalytic activity of the material is proposed.
电催化水分解是一种可行的技术，可从可再生资源中产生氢气。析氧反应（OER）的动力学比析氢反应慢且过电位更高，是限制整体水分解的瓶颈。开发高效的OER催化剂以降低阳极过电位至关重要。在此，通过简单的一步水热法合成了直接生长在碳布上的Ni、Co、Yb-FeOOH纳米棒阵列。掺杂的Ni和Co可占据FeOOH中的Fe和Fe位点，增加氧空位浓度，而具有较大离子半径的掺杂Yb可占据间隙位点，这导致更多的边缘位错。氧空位和边缘位错极大地丰富了FeOOH/CC中的活性位点。此外，密度泛函理论计算证实，Ni、Co和Yb的掺杂调节了主要活性Fe位点的电子结构，使其d带中心更接近费米能级，并降低了OER速率决定步骤的吉布斯自由能变化。当电流密度达到10 mA cm时，Ni、Co、Yb-FeOOH/CC的过电位仅为230.9 mV，塔菲尔斜率为22.7 mV dec。特别地，提出了一种多阳离子掺杂与氧空位和边缘位错协同相互作用以增强材料OER催化活性的机制。
