“…The chronicle of semiconductors as a photocatalyst, which can be used for water splitting, had been proven by Fujishima and Honda during the 20th century, and it paved the way for exploration of various semiconductor materials for photocatalytic water splitting. − Generally, the most important steps which affect a photocatalyst are light absorption, photoexciton generation, charge separation, and their transfer to the respective redox reaction. ,− In this scenario, a motley of narrow and wide band gap semiconductors such as metal sulfides (ZnCdS, CuInS 2 , Cu 2 S, ZnS, and CdS), − metal oxides (BiOCl, TiO 2 , SrTiO 3 , ZnO, NiO, CuO, BiVO 4 , etc. ), − oxynitrides, metal-free semiconductors, and oxysulfides were explored for photocatalytic activity. − In spite of many innovations, some hindrances appeared to be indispensable. The major setback is the shortage of effective usage of visible light which contributes about half of the solar spectrum, fast recombination of charged species, and lack of active sites over the catalyst surface, which is found to be inevitable .…”