Recent developments and perspectives in CdS-based photocatalysts for water splitting

Over the past few years, many approaches have been developed progressively to produce hydrogen (H2) from water under solar light irradiation. This process of fuel production is clean, potentially cost-effective, and environment-friendly. At present, however, current technologies are unable to meet the industrial requirements because of high cost, low photoresponse, and insufficient catalytic performance. Among water splitting photocatalysts, CdS is considered to be an interesting and important material owing to its low cost, prominent catalytic activity, high absorption in the visible spectrum, and the suitable positions of its conduction (CB) and valence (VB) bands. There are, however, some associated problems such as the rapid recombination of photogenerated electron-hole pairs and photocorrosion that have severely hampered its practical usage. The efficient conversion of water to H2 depends on the extent to which the charge carriers, especially the electrons, are first generated and then have sufficient life-Time for their effective utilization. This review highlights work over the past several years to improve the photocatalytic efficiency and stability of CdS for H2 production from water.