Development\nof Cobalt\nOxide-Decorated Reduced Graphene\nOxide-Supported Nickel Alloy Coating for Efficient Photocatalytic\nHydrogen Generation

Abstract

Being a narrow band gap semiconductor,\nthe photocatalytic\nactivity\nof bare Ni₂P is highly limited. However, a proper band\ngap tuning of Ni₂P through effective composite formation\nfurnishes a fruitful strategy for developing active photocatalytic\nmaterials. In this regard, the present work reports the application\nof an efficient photocatalytic ternary composite in the form of a\ncoating formed from CoO/rGO and Ni₂P. The simultaneous\nreduction of GO to rGO disperses crystalline CoO nanoparticles in\nit. The CoO-embedded rGO nanosheet can act as an efficient conducting\nmaterial that helps to mediate the redox reactions in CoO and Ni₂P. CoO/rGO enriches the catalytically active sites in the\nNi₂P surface with an improvement in the surface topography.\nMoreover, the possibilities of interactions such as hydrogen bonding\namong the oxygen functional groups in CoO/rGO, with phosphorus in\nNi₂P, lead to an intimate contact among them for the fast\nelectronic movement for proton reduction. Consequently, the CoO/rGO-Ni₂P composite coating displays a benchmark performance for solar-driven\nhydrogen generation and produces 4.98 mmol/g hydrogen for 1 h irradiation\nafter a successful compositional tuning. The long-lasting activity\nand excellent stability of the composite coating, even after 15 cycles,\nare attributed to the additional role of Ni₂P as a catalyst\nsupport bed for CoO/rGO which can impart stability to the entire catalyst\nsystem.