Preparation and electrocatalytic performance of novel-integrated Ni-Mo sulfide electrode materials for water splitting

Abstract

Advanced electrode materials for electrocatalysis of electrolytic decomposition are crucial materials in the field of hydrogen production from renewable energy. In this work, a new type of integrated hydrogen evolution electrode material was synthesized by selective acidification etching and in situ growth technology. A novel-integrated Ni-Mo sulfide electrode material with a three-dimensional network structure was successfully prepared using a two-step method (convenient surface modification and in situ growth techniques), which involved surface modification at 30% HNO₃ for 10 min and followed by annealing treatment at 600 °C for 1 h with 10 °C·min⁻¹ heating rate. The structure displayed an electrochemical active surface area (ECSA) of 30.125 mF·cm⁻², calculated on 0.10–0.30 V (vs. RHE) CV curves with a 5–50 mV·s⁻¹ sweep rate range. The ECSA of other samples was also tested by aforementioned methods, which had great distinction on ECSA with different samples. The novel-integrated Ni-Mo sulfide electrode material appeared to have extremity electrochemical performance in a three-electrode configuration employing 1 M KOH solution as an electrolyte, including an excellent hydrogen evolution overpotential of 346 mV at the current density of 500 mA·cm⁻², superior Tafel slope with 103 mV·dec⁻¹. Such outstanding electrochemical performances of the novel-integrated Ni-Mo sulfide electrode materials were directly related to the distinctive integrated structure. Therefore, it was facility to find that the successful preparation of novel-integrated Ni-Mo sulfide electrode material provided more selection opportunities for alkaline electrolysis of water and offered an innovative mentality for the preparation of other types of electrode materials.

Graphical abstract