In situ grown molybdenum sulfide on Laponite D clay: Visible-light-driven hydrogen evolution for high solar-to-hydrogen (STH) efficiencies

Clay minerals have been proven as much attractive support materials for catalytic applications owing to its non-toxicity, low-cost, efficient surface area, ion exchange capacity and flat sheets. Laponite D is a layered silicate disc-type clay, which can provide efficient photocatalytic activity under visible light radiation due to its catalytic active surfaces and zwitterionic property. Herein, the photocatalytic studies based on the incorporation of MoSx onto Laponite D clay structure were carried out for the first time. Time dependent photocatalytic reactions were performed by using Laponite D, triethanolamine and eosin-Y dye as catalytically active surface, sacrificial electron donor and photosensitizer, respectively, in the absence and presence of ammonium tetrathiomolybdate as the precursor of in situ photodeposited MoSx co-catalyst. Laponite D/MoSx exhibited higher photocatalytic activity and stability than that of free-Laponite D and free-MoSx. Laponite D/MoSx enhanced the photocatalytic activity approximately 7- and 2-times compared to the free- Laponite D and free-MoSx, respectively. In addition, solar-to-hydrogen (STH) efficiencies are reached about 26% under solar irradiation for the Laponite D/MoSx in the presence of aqueous eosin-Y and triethanolamine media. Moreover, photocatalytic activities of eosin-Y sensitized Laponite D, free-MoSx and Laponite D/MoSx were compared to different xanthene type sensitizers.