“…H 2 production is frequently driven by renewable and non-renewable energy resources, such as fossil fuels— in particular steam methane reforming [ 8 , 9 ] and the NAFTA reform [ 10 , 11 ]—from biomass [ 12 ], and from biological sources [ 13 , 14 , 15 , 16 ]. Unfortunately, these H 2 production methods are expensive, partially efficient, and environmentally polluting, as well as also producing low-purity H 2 [ 17 , 18 , 19 , 20 ]. Meanwhile, the unique way to produce the cleanest H 2 is from the well-known process of water electrolysis or, as commonly called, water splitting.…”