A critical look at alternative oxidation reactions for hydrogen production from water electrolysis

Electrocatalytic water splitting using renewable electricity is widely recognized as a promising approach toward sustainable green hydrogen production. However, the energy efficiency of conventional water electrolysis is hindered by sluggish kinetics of the anodic oxygen evolution reaction. Several innovative strategies have been proposed to replace the anodic reaction, aiming toward lowering the levelized cost of hydrogen. One of the most notable emerging strategies is to pursue alternative oxidation reactions. Here, we take a critical look at an array of alternative oxidation reactions. The analysis includes reactions that target wastewater contaminants as sacrificial reagents. Additionally, processes that boast the dual functionality of biomass sourcing and consequent partial reforming to hydrogen and value-added byproducts are examined. The critique offered herein paints a clear picture of current challenges and bottlenecks of alternative oxidation reactions as an approach toward meeting industrial hydrogen production needs. Further, key technical perspectives are provided with the aim of advancing the application of alternative oxidation reactions.