|
|||||
|
|
Improving Electrocatalytic Oxygen Evolution through Local Field Distortion in Mg/Fe Dual-site Catalysts |
|
| Authors: | Jing Zhang Yufeng Zhao Wanting Zhao Jing Wang Yongfeng Hu Chengyu Huang Xingli Zou Yang Liu Dengsong Zhang Xionggang Lu Hongjin Fan Yanglong Hou |
| Affiliation: | 1. College of Sciences&Institute for Sustainable Energy, Shanghai University, Shanghai, 200444 China Contribution: Investigation (lead), Writing - original draft (lead);2. College of Sciences&Institute for Sustainable Energy, Shanghai University, Shanghai, 200444 China;3. School of Materials Science and Engineering, Peking University, Beijing Key Laboratory for Magneto Electric Materials and Devices (BKLMMD), Beijing, 100871 China Contribution: Investigation (supporting);4. State Key Laboratory of Metastable Materials Science and Technology, Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse, Yanshan University, Qinhuangdao, 066004 China;5. Canadian Light Source, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Contribution: Investigation (supporting);6. College of Sciences&Institute for Sustainable Energy, Shanghai University, Shanghai, 200444 China Contribution: Investigation (supporting);7. State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai, 200444 P. R. China Contribution: Investigation (supporting);8. School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 639798 Singapore Contribution: Investigation (supporting);9. School of Materials Science and Engineering, Peking University, Beijing Key Laboratory for Magneto Electric Materials and Devices (BKLMMD), Beijing, 100871 China |
| Abstract: | Transition metal single atom electrocatalysts (SACs) with metal-nitrogen-carbon (M−N−C) configuration show great potential in oxygen evolution reaction (OER), whereby the spin-dependent electrons must be allowed to transfer along reactants (OH−/H2O, singlet spin state) and products (O2, triplet spin state). Therefore, it is imperative to modulate the spin configuration in M−N−C to enhance the spin-sensitive OER energetics, which however remains a significant challenge. Herein, we report a local field distortion induced intermediate to low spin transition by introducing a main-group element (Mg) into the Fe−N−C architecture, and decode the underlying origin of the enhanced OER activity. We unveil that, the large ionic radii mismatch between Mg2+ and Fe2+ can cause a FeN4 in-plane square local field deformation, which triggers a favorable spin transition of Fe2+ from intermediate (dxy2dxz2dyz1dz21, 2.96 μB) to low spin (dxy2dxz2dyz2, 0.95 μB), and consequently regulate the thermodyna-mics of the elementary step with desired Gibbs free energies. The as-obtained Mg/Fe dual-site catalyst demonstrates a superior OER activity with an overpotential of 224 mV at 10 mA cm−2 and an electrolysis voltage of only 1.542 V at 10 mA cm−2 in the overall water splitting, which outperforms those of the state-of-the-art transition metal SACs. |
| Keywords: | Oxygen evolution reaction Spin regulation Local field distortion Dual-site Overall water splitting |