“…In an effort to reduce the dependence on fossil fuels as energy sources, much research has been carried out to search for new clean fuels. − The generation of dihydrogen (H 2 ) gas as a carbon-free fuel from water splitting has attracted much attention. ,, Water splitting consists of two parts; the oxidation of water, which generates dioxygen, and the reduction of protons, which produces H 2 . , While platinum metal is able to catalyze proton reduction readily, its high cost and rarity prevent widespread applications. , A lot of effort has thus been devoted to finding inexpensive, earth-abundant catalysts to drive the proton reduction process more efficiently. , …”