Electrocatalytic water oxidation of coral-like porous Zn-CoP nanohybrids synergistically inspired by photothermal and photoelectronic effects

Abstract

The electrocatalytic oxygen evolution reaction (OER) plays a crucial role in the recycling of sustainable energy by coupling with reduction reactions, but still suffers from sluggish kinetics and a high overpotential. In this work, we report an electrocatalytic strategy synergistically inspired by photothermal and photoelectronic effects to substantially ameliorate the reaction kinetics of the OER, with coral-like porous Zn-doped CoP nanohybrids (Zn-CoP NHs) as the typical catalyst. It is demonstrated that the Zn dopant both modifies the electronic structure of the CoP subject and enhances the light energy capture capacity of the Zn-CoP NHs, leading to distinct photothermal and photoelectronic responses. The notable photothermal effect can offset the endothermic enthalpy change of the OER exactly and accelerate the interface charge transfer. The remarkable photoelectronic response of the Zn-CoP NHs lowers the OER activation energy (from 29.2 kJ mol⁻¹ to 10.2 kJ mol⁻¹), thereby contributing to improved reaction kinetics. Moreover, the coral-like porous architecture of the Zn-CoP NHs provides abundant electrochemical active sites and assists mass transfer. Benefiting from these promoting effects, the Zn-CoP NHs achieve remarkable electrocatalytic OER performances under a light irradiation of 808 nm, with an overpotential of 189 and 297 mV to afford a current density of 10 and 100 mA cm⁻², respectively, outperforming those without light illumination (260 and 345 mV) and its CoP counterpart (308 and 386 mV), as well as some recently reported transition metal compounds. In comparison with conventional microstructure and electronic structure tuning strategies, this work reveals a unique and universal infrared light-assisted route, injecting new vitality into the development of new and advanced electrocatalytic platforms.