The Oxygen Evolution Performance Of Molecule-Controlled Ni-Co-Based Materials

The electrochemical water decomposition driven by renewable electricity produces hydrogen（H₂）and oxygen（O₂）.Because of its purity and cleanliness,it is considered to have great potential to solve environmental degradation and energy crisis.High prices and scarce earth reserves of precious metals limit their application and conversion in actual production.Transition metal catalysts have been intensively studied for effective water splitting,but it is still necessary to reduce costs while improving the activity and stability of OER catalysts.Make greater efforts.This paper is mainly divided into two parts:The first part uses a simple method to prepare non-equal stoichiometric Ni O_x.Pure stoichiometric Ni O is inevitably an insulator,which hinders the transfer and transport of electrons in catalysis.The non-stoichiometric Ni O_x is a p-type semiconductor with a wider band gap.The conductive interface of non-stoichiometric Ni O_x NCs was successfully prepared,where the p-type conductivity of Ni O_x comes from the positive charge compensation of two Ni²⁺vacancies.The valence band（VB）of Ni O_x can be adjusted well,so the strong electronic interaction will cause the electronic structure adjustment,thereby optimizing the binding energy of the OOH intermediate.In the process of alkaline water decomposition,the non-stoichiometric Ni Ox NC showed high efficiency and high stability in OER.The overpotential reached 322 m V（1.56 V vs.RHE）at 10 m A cm^-2,and the Tafel slope was only 105.17 m V dec^-1.Detailed studies have shown that high-density defects combine with oxygen atoms to form Ni OOH species,which is conducive to OER kinetics.This work provides valuable broad insights for the construction of robust non-stoichiometric metal oxide electrocatalysts and encourages large-scale practical applications.In the second part,we used the strategy mediated by the liquid-liquid interface at the oil-water interface to obtain ultra-thin Co-S-Se nanosheets with partial separation domains.Co-S-Se ultra-thin nanosheets exhibited various sheet-like morphologies of different sizes,and the average thickness was 0.83 nm.Ternary ultra-thin Co_0.45S_0.38Se_0.17 nanosheets show excellent OER performance,with an overpotential of290 m V at 10 m A cm^-2（RHE at 1.52 V）,and Tafel slope at 74.5 m V dec^-1.Co-S-Se nanosheets can rearrange the electron density around the center of the catalytic metal and increase electron transfer.DFT calculations show that the charge in the partial separation domain can improve the electrocatalytic performance,which proves to adjust the electroreduction performance.This work illustrates the potential of ternary transition metal alloy chalcogenides in energy conversion due to the special atomic and electronic structure,which may contribute to the manufacture of high-performance electrocatalysts.