Back Cover Chem. Eng. Technol. 1/2016

Abstract

AbstractReduced Graphene Oxide Composite of Gallium Zinc Oxynitride Photocatalyst with Improved Activity for Overall Water SplittingIncreasing the level of greenhouse gases would put human health and nutrition in danger in the near future. Holding the CO2 level on its current level requires invention, development, and implementation.Solar energy is the most abundant source of energy on the planet. There are various methods to harvest solar energy. Converting the solar irradiation to hydrogen fuel through water splitting on the surface of a visible light activated photocatalyst, is one of the most promising technologies, and has grasped significant attention lately.Gallium‐zinc oxynitride (GaN:ZnO) solid solution has demonstrated outstanding activity for overall water splitting under visible light. However, like other proposed photocatalysts, a high rate of photo‐excited charge recombination limits its efficiency. Since the electrons tend to move towards the media with higher conductivity and electron mobility, fabrication of nanocomposites of highly conductive materials and photocatalyst would be beneficial.This article proposes a method to address the challenging obstacle in the overall solar water splitting process: the undesirable charge recombination. For the first time, reduced graphene oxide (RGO) was utilized as electron sink in an integrated composite with GaN:ZnO solid solution. Precursors and individual components of GaN:ZnO‐RGO composites have been characterized via various techniques.Fabrication of GaN:ZnO‐RGO not only improved the distribution of GaN:ZnO solid solution over the surface of RGO nanosheets, but also enhanced the rate of charge separation, as confirmed through scanning electron microscopy (SEM) and photoluminescence (PL) analysis. Reduction of graphene oxide (GO) to RGO was confirmed through X‐ray photoelectron spectroscopy (XPS) narrow scan analysis. Moreover, evidence of nanoparticles and aggregates of Rh, as the active sites of the water splitting reaction observed on the surface of RGO nanosheets, suggest the existence of sufficient electron density for photo‐reduction of the Rh precursor.Since the immobilized photocatalyst thin film on the surface of a conductive substrate is believed to be an ideal design for practical application, the proposed integrated photocatalytic system effectively contributes toward the designing of a feasible solar harvesting device. The technique reported in this article, can be applied for various photocatalysts in order to develop a highly efficient photocatalytic system. Authors believe that the presented scientific report would offer benefits to researchers not only in material synthesis and characterization area, but also in the field of electrochemistry and photonics.Babak Adeli and Fariborz TaghipourReduced Graphene Oxide Composite of Gallium Zinc Oxynitride Photocatalyst with Improved Activity for Overall Water SplittingChem. Eng. Technol. 2016, 39 (1), 142–148DOI: 10.1002/ceat.201500239