Li Xuan, Deng Chen, Kong Yan, Huo Qihua, Mi Lingren, Sun Jianju, Cao Jianyong, Shao Jiaxin, Chen Xinbao, Zhou Weiliang, Lv Miaoyuan, Chai Xiaoyan, Yang Hengpan, Hu Qi, He Chuanxin
Department of Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui Province, 230026, P. R. China.
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China.
Angew Chem Int Ed Engl. 2023 Oct 2;62(40):e202309732. doi: 10.1002/anie.202309732. Epub 2023 Aug 29.
Heteroatom doping has emerged as a highly effective strategy to enhance the activity of metal-based electrocatalysts toward the oxygen evolution reaction (OER). It is widely accepted that the doping does not switch the OER mechanism from the adsorbate evolution mechanism (AEM) to the lattice-oxygen-mediated mechanism (LOM), and the enhanced activity is attributed to the optimized binding energies toward oxygen intermediates. However, this seems inconsistent with the fact that the overpotential of doped OER electrocatalysts (<300 mV) is considerably smaller than the limit of AEM (>370 mV). To determine the origin of this inconsistency, we select phosphorus (P)-doped nickel-iron mixed oxides as the model electrocatalysts and observe that the doping enhances the covalency of the metal-oxygen bonds to drive the OER pathway transition from the AEM to the LOM, thereby breaking the adsorption linear relation between *OH and *OOH in the AEM. Consequently, the obtained P-doped oxides display a small overpotential of 237 mV at 10 mA cm . Beyond P, the similar pathway transition is also observed on the sulfur doping. These findings offer new insights into the substantially enhanced OER activity originating from heteroatom doping.
杂原子掺杂已成为一种提高金属基电催化剂析氧反应（OER）活性的高效策略。人们普遍认为，这种掺杂不会使OER机制从吸附质演化机制（AEM）转变为晶格氧介导机制（LOM），且活性增强归因于对氧中间体的结合能优化。然而，这似乎与掺杂的OER电催化剂的过电位（<300 mV）远小于AEM的极限（>370 mV）这一事实不一致。为了确定这种不一致的根源，我们选择磷（P）掺杂的镍铁混合氧化物作为模型电催化剂，并观察到掺杂增强了金属-氧键的共价性，从而推动OER途径从AEM转变为LOM，进而打破了AEM中OH和OOH之间的吸附线性关系。因此，所得的P掺杂氧化物在10 mA cm 时显示出237 mV的小过电位。除了P之外，在硫掺杂上也观察到了类似的途径转变。这些发现为杂原子掺杂导致OER活性大幅增强提供了新的见解。
