Nanomaterials-Based Water Splitting: How Far Are We from a Sustainable Solution?

A comprehensive review of hydrogen production and storage: A focus on the role of nanomaterials

“…Water splitting involves water decomposition into H2 and O2 through a reaction involving charge carriers. This promising H2 generation process has improved over time, and there are currently four distinct methods explored for this purpose; these include thermochemical (thermolysis), electrochemical (electrolysis), photochemical (photolysis), and photoelectrochemical methods [40]. These methods are still subjected to ongoing research and are at different levels of development.…”

“…Therefore, it has limited its application in the large-scale production of H2, despite offering more than 77% efficiency [40,41]. During thermochemical water splitting, the water should be heated above 2500°C to achieve hydrogen separation [14].…”

“…donor that removes the photogenerated holes from the catalyst [40]. The sacrificial donors, which are primarily carbon-based molecules, get oxidized in the process to form CO2.…”

“…This has environmental implications and must be addressed to make the process more attractive. There is, therefore, a recommendation that the term "water splitting" should not be used when a sacrificial donor is involved [40]. In addition, there are also concerns about the low conversion efficiency, high cost of conversion, and unstable catalysts associated with photocatalytic water splitting [46].…”

“…Photoelectrochemical hydrogen production involves splitting water with sunlight and specialized semiconductors called photoelectrochemical materials [40]. The semiconductor materials are similar to those used in photovoltaic solar electricity generation.…”