Executive Summary : | Water electrolysis is a promising solution to combat the depletion of fossil fuels and global warming. It involves two key processes: hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode. OER is often considered the bottleneck for the overall water splitting process, but it faces challenges such as high overpotential, sluggish kinetics, and instability in near neutral pH. To address these issues, it is essential to replace the kinetically sluggish OER process with an easily oxidizable substrate. C-H bonds of organic moieties with bond dissociation free energy (BDFE) range from 70-90 kcal mol-1 are ideal substrates for anodic oxidation reactions. These benzylic C-H bonds are abundant in biomass and can afford platform chemicals. In a hybrid water electrolysis system, hydrogen production at the cathode is viable with large current density and lower cell potential. Despite significant innovation in hybrid water electrolysis, efforts have been limited to nickel-based catalysts due to their use as anodes in commercial water electrolyzers. Copper-based systems are emerging as efficient water oxidation catalysts due to their lower overpotential and easier formation of oxyl species, which are proposed to be the key intermediate of OER. Copper-based catalysts are more stable under neutral conditions and play a vital role in substrate oxidation mechanisms. Future research on copper-based catalysts is needed for large-scale implementation in hybrid water electrolysis systems for value-added chemical production and hydrogen generation at the cathode. Ensuring assembly works under solar illumination is a significant step forward for green synthesis of value-added chemicals and hydrogen production under mild conditions. |