Modulation to favorable surface adsorption energy for oxygen evolution reaction intermediates over carbon-tunable alloys towards sustainable hydrogen production

Because of the value of hydrogen as the future energy in no distant time, demand for efficient and scalable hydrogen production via electrochemical water splitting process has recently attracted considerable attention from industrial and scientific communities. Yet, several challenges associated with production remain to be addressed. One of the overriding challenges is the sluggish kinetics of oxygen evolution reaction (OER), which can have significant impact on the H₂ production due to overpotential. To overcome this limitation, developing low-cost, robust and stable electrocatalysts very close to the same electrode activity as seen for iridium metal is crucial to solving the efficiency issue in the process. Therefore, timely review of progress in the field is vital to identify the electrocatalytic systems with the highest potential and, more importantly, to understand the factors which have positive contribution towards the electrocatalysts performance. We reviewed the progress made in the direction of designing binary and ternary alloys of transition metal-based electrocatalysts tuned with carbon materials. The review focuses more on the modulation of structural design and electronic conductivity that have been carried out by manipulating chemical compositions to moderate the surface adsorption free energies of the reaction intermediates, targeted to reduce overpotential. The strategic routes are discussed thoroughly with respect to the OER mechanisms and their derived-descriptors. However, numerous opportunities still remain open for exploration, particularly on the key challenge to obtain a route to unify electronic structure-activity and activity-multi-descriptor relationships for rational design of efficient electrocatalysts.