Photo-sensitive CuS/NiO heterostructure electrocatalysts for energy-saving hydrogen evolution reaction at all pH conditions

Heterostructures based on transition metal chalcogenides/oxides have gained significant interest in the application of electrochemical hydrogen evolution reaction (HER) due to their distinct characteristics and excellent electrocatalytic activity. Herein, we developed an earth-abundant, low-cost, and light-sensitive CuS/NiO (CSNO) heterostructure electro-catalyst via a facile co-precipitation method and fabricated it on silver-modified con-ducting cellulose paper for HER. Under all pH level, the performance of the visible light -sensitive HER catalyst has been examined. With the illumination of light, HER perfor-mance at all pH, which conserves energy has been seen. In basic media, the value of overpotential was improved to-290 mV vs RHE at 20 mA/cm2 under light-illuminating conditions. Similarly, with light illumination, the overpotential of the CSNO10/Ag- modified paper is reduced to-363 mV and-312 mV vs RHE in an acidic and in a near-neutral medium, respectively. In addition to that, the values of the Tafel slopes and charge -transfer resistance also decreased indicating relatively faster HER kinetics in the presence of light at all pH levels. Also, The CSNO10 electrode exhibits stability of more than 24 h in 1 M PBS with an overpotential of-368 mV vs RHE at 20 mA/cm2. The overall performance of the CuS/NiO heterostructure is a good sign to be explored it as a low-cost and efficient electrocatalyst for the large-scale production of green hydrogen (H2).(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.