Solar-boosted electrocatalytic oxygen evolution via a 2D/2D heterostructure constructed by integrating reduced graphene oxide on NiFe-LDH nanosheets

Abstract

Multi-physical fields driven catalysis for energy conversion has attracted increasing research interests. Introducing solar energy to boost the oxygen evolution reaction (OER) activity of electrocatalyst via photothermal effect is an effective way to reduce energy consumption of water electrolysis. However, it still remains challenging to design advanced catalyst that can fully utilize the energy of each physical field to promote the kinetically sluggish OER. Herein, we report a two-dimensional (2D)/2D heterostructure constructed by integrating the reduced graphene oxide (rGO) with high photothermal conversion efficiency on the surface of catalytically active nickel-iron layered bimetallic hydroxide (NiFe-LDH) nanosheet arrays. The 2D/2D heterointerface in rGO/NiFe-LDH enables the intense contact between rGO and NiFe-LDH, facilitating the generated local heat transfer and significantly reducing the overpotential towards OER under solar irradiation. The temperature of rGO/NiFe-LDH composite supported on carbon paper (rGO/NiFe-LDH/CP) rises rapidly from 30.0 °C to 58.5 °C after exposure to one-sun irradiation. Remarkably, the rGO/NiFe-LDH/CP exhibits a low overpotential of 197 mV to achieve the current density of 10 mA cm⁻² for OER under solar irradiation. Furthermore, the Tafel slope of rGO/NiFe-LDH/CP decreases from 63.4 to 51.5 mV dec⁻¹ with light irradiation, suggesting the integrated rGO photothermal layer not only reduce the thermodynamic barrier of OER but also accelerate the OER kinetics. In addition, the rGO can accelerate the charge transfer at the catalyst surface and increase the electrochemical specific surface area, all of which contributes to the enhanced electrocatalytic activity for OER. The solar-boosted electrocatalysis towards OER also shows good stability, indicating opportunities for practical application.