“…Sustainable use of material, scalable synthesis, biosafety, and abundance of material have become integral and important considerations in the material development process. Metal oxide semiconductors acting as photoharvesters form a broad class of photocatalytic materials, and TiO 2 , ZnO, WO 3 , CuO, and Cu 2 O are some of the most cost-effective photocatalytic materials being researched. − Optimization of material properties enabling efficient production of electron–hole pairs from abundant solar photons, effective charge separation and transportation with minimal intermediate losses, resistance to photocorrosion, and long-term stability of the material, especially under aqueous environments, have become critically important, while careful choice of an accompanying metal co-catalyst can further enhance the associated photocatalytic redox reaction. , Fujishima and Honda in 1972 realized the first ever electrochemical photolysis of water using TiO 2 , and over the years the material has demonstrated its promise as an excellent photocatalyst in a variety of photocatalytic applications. − However, its wide band gap (>3.0 eV) ,, only allows harvesting the ultraviolet end of the solar spectrum, making its photoelectron yield slightly low for terrestrial applications.…”