Fabrication of 2D+1D nanoarchitecture for transition metal oxide modified CdS nanorods: A comparative study on their photocatalytic hydrogen-generation efficiency

Abstract

We report the formation of Mo1−xWxO3-CdS (0 ≤ x ≤1) nanophotocatalysts by a combination of solid-state and solution-impregnation processes. The formation of 2D+1D heterostructured composite was revealed by electron microscopy and the structure of ternary co-catalyst and photocatalysts were confirmed by spectroscopic analyses. The H2 evolution activity of the nanocomposites was assessed via photocatalytic splitting of water under the irradiation of visible light. All the nanocomposites studied here exhibit notable catalytic activity and good photostability using lactic acid as the sacrificial electron donor compared to a pristine compound. Among these nanocomposites, WO3-CdS shows superior activity with H2 evolution rates of 15.19 mmolg−1h−1, 28 times higher than the pure CdS. The WO3-CdS photoactivity is not only superior among all the composites studied here but also highest among the reported WO3 composite catalysts to date. The novel construction of the oxide-based nanocomposite photocatalyst shown here efficiently enhances the catalytic activity by effective separation of charge carriers and inhibits photocorrosion of CdS nanorods. The apparent quantum yield of the hydrogen evolution for WO3-CdS was found to be 8% in the visible spectral range. The disparity of the catalytic ability between MoO3 and WO3 and the variance among the compositions was unraveled through optical band-offset alignment with respect to CdS. Though the 2D+1D novel fabrication is common to all the composites, the difference in the type of band alignment MoO3 (type-I) and WO3 (type-II) with CdS plays a highly significant role in the co-catalytic activity.