Enhanced hydrogen evolution reaction via regulating the adsorbability between 2D CoO nanosheets and CC substrate

In recent years, bifunctional electrocatalysts, nanomaterials directly grown on the substrate for application towards the hydrogen evolution reaction (HER), have become of interest for sustainable and clean energy technologies. However, the influence of interfacial interactions between the electrode materials and substrate on device performance remains unclear and is rarely investigated. Herein, we report two-dimensional (2D) CoO nanosheets grown on carbon cloth (CC) (2D CoO/CC) to construct a hybrid electrocatalyst with a seamlessly conductive network. By a series of structure analyses, we recommend that the CoO nanosheets and CC are connected via adsorption. The 2D CoO/CC nanosheets show superior HER performance to the commercial Pt/C and CoO(aq.)/CC nanosheets, including onset potentials of 2 mV, low overpotential of 22 mV at 10 mA cm^-2 and Tafel slope of 37 mV dec^-1. The results of density functional theory (DFT) calculations reveal that the adsorbability plays an important role in determining the performance of the electrocatalysts for the HER. This work provides a new insight into the interfacial interactions between the electrode material and the substrate in electrochemical devices, and paves the way for the rational design and construction of high-performance electrochemical devices for practical energy applications.