The electrocatalytic activity of transition-metal-based compounds is closely related to the electronic con-figuration.However,optimizing the surface electron spin state of catalysts remains a challenge.Here,we developed a spin-state and delocalized electron regulation method to optimize oxygen evolution reaction(OER)performance by in-situ growth of NiCo2(OH)x using Oswald ripening and coordinating etching pro-cess on MXene and plasma treatment.X-ray absorption spectroscopy,magnetic tests and electron para-magnetic resonance reveal that the coupling of NiCo2(OH)x and MXene can induce remarkable spin-state transition of Co3+and transition metal ions electron delocalization,plasma treatment further optimizes the 3d orbital structure and delocalized electron density.The unique Jahn-Teller phenomenon can be brought by the intermediate spin state(t2g5eg1)of Co3+,which benefits from the partial electron occupied eg orbitals.This distinct electron configuration(t2g5eg1)with unpaired electrons leads to orbital degener-acy,that the adsorption free energy of intermediate species and conductivity were further optimized.The optimized electrocatalyst exhibits excellent OER activity with an overpotential of 268 mV at 10 mA cm-2.DFT calculations show that plasma treatment can effectively regulate the d-band center of TMs to opti-mize the adsorption and improve the OER activity.This approach could guide the rational design and dis-covery of electrocatalysts with ideal electron configurations in the future.

Jingyao Xu;Xia Zhong;Xiaofeng Wu;Ying Wang;Shouhua Feng

State Key Laboratory of Inorganic Synthesis and Preparative Chemistry,College of Chemistry,Jilin University,Changchun 130012,Jilin,China;Chinese Acad Sci,Inst Met Res,Shenyang Natl Lab Mat Sci,Shenyang 110016,Liaoning,China;Univ Sci&Technol China,Sch Mat Sci&Engn,Shenyang 110016,Liaoning,China;State Key Laboratory of Rare Earth Resource Utilization,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,Jilin,China

能源化学

[1]Jingyao Xu;Xia Zhong;Xiaofeng Wu;Ying Wang;Shouhua Feng-.Optimizing the electronic spin state and delocalized electron of NiCo2(OH)x/MXene composite by interface engineering and plasma boosting oxygen evolution reaction)[J].能源化学,2022(08):129-140

Co3+and,t2g5eg1,degener

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