Nickel-based coatings as highly active electrocatalysts for hydrogen evolution reaction: A review on electroless plating cost-effective technique

The development of renewable and clean sources of energy, such as hydrogen, to address the energy shortages and environmental concerns caused by fossil fuels, is a well-recognized global challenge. Electrochemical water splitting has advanced as an emerging technology for sustainable and high-purity hydrogen generation from water. This process relies on high-performance catalysts to efficiently convert water into oxygen and hydrogen through the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Although platinum has been widely used as a commercially available HER electrocatalyst, its expensivity, scarcity, and low stability limit its large-scale application. Consequently, there exists an urgent need to develop low-cost, efficient, and stable non-noble metal HER electrocatalysts, which remains a significant challenge. In recent years, nickel (Ni) and its alloys have emerged as highly promising HER catalytic electrode materials, offering an alternative to platinum across a wide pH range. Ni electroless plating as an autocatalytic chemical reduction process is a facile, scalable, environmentally friendly, low-cost, and energy-saving technique for HER electrode fabrication. This review focuses on the HER electrocatalytic behavior of Ni-based coatings synthesized using the electroless plating technique. The aim is to highlight the tremendous potential and practical applicability of such coatings as HER electrocatalysts for hydrogen production through water splitting. It is hoped that this review will serve as a valuable guide for readers interested in designing and developing HER electrocatalysts with exceptional catalytic performance, utilizing a simple and scalable electroless plating technique.