Semiconductor-based Materials for Water-Splitting Applications

The drastic depletion of fossil fuels and the rising energy crisis can be tackled only by replacing these fossil fuels with renewable and sustainable energy sources. One such efficient resource is clean hydrogen fuel, which can be easily generated by the photo-electrocatalytic splitting of water employing the abundant sunlight reaching the earth. Mostly, the water splitting process occurs at a semiconductor electrode, where the optoelectronic property of the semiconductor greatly influences the solar to hydrogen efficiency. Thus, the nature of the semiconductor has a pivotal role in achieving ideal efficiency in the electrocatalytic process. A variety of systems have been explored as semiconductor materials ranging from metal oxides, binary, ternary, multifunctional, and nanostructures, to organic polymers, metal and covalent organic frameworks, and covalent triazine frameworks. Each semiconductor system displays exceptional advantages characteristic to them, while countered by certain disadvantages. The downsides of conventional semiconductors can be overcome by the synergistic effect in heterojunctions developed by suitably doping or combining materials. Furthermore, computational quantum mechanics-based simulations and theoretical calculations can provide insights into optoelectronics and photocatalytic activity to identify potential semiconductor materials.