Orbital Occupancy Modulation to Optimize Intermediate Absorption for Efficient Electrocatalysts in Water Electrolysis and Zinc-Ethanol-Air Battery.

Spin engineering is a promising way to modulate the interaction between the transition metal d-orbital and the reaction intermediates and thus enhance the catalytic kinetics. Herein, we report an innovative strategy to modulate the spin state of Co by regulating its coordinating environment. We first prepared o-c-CoSe 2 -Ni as pre-catalyst, then in situ EIS and in situ Raman spectroscopy were employed to prove phase transition, and CoOOH/Co 3 O 4 was formed on the surface as active sites. In hybrid water electrolysis, the voltage has a negative shift, and in zinc-ethanol-air battery, the charging voltage was lowered and the cycling stability was greatly increased. Coordinated atom substitution and crystalline symmetry change were combined to regulate the absorption ability of reaction intermediates with balanced optimal adsorption. Coordinated atom substitution weakens the adsorption while the crystalline symmetry change strengthens the adsorption. Importantly, the tetrahedral sites were introduced by Ni doping which enables the co-existence of four-coordinated sites and six-coordination sites in o-c-CoSe 2 -Ni. The dz 2 + dx 2 -y 2 orbital occupancy decreased after the atomic substitution, while increased after replacing the CoSe 6 -O h field with CoSe 6 -O h /CoSe 4 -T d caused by the Ni doping. This work explored a new direction for the preparation of efficient catalysts for water electrolysis and innovative zinc-ethanol-air battery. This article is protected by copyright. All rights reserved.