Manufacturing Cu_xZn_(1-x)S Photocatalysts and Their Solar H_2 Production Characteristics with Varying Cu Content

摘要

Solar water splitting is an attractive method for producing hydrogen from renewable natural resources, and heterostructure photocatalysts have been widely investigated for photocatalytic applications. Hetero-component photocatalysts can reduce the charge recombination process by improving electron utilization, and are considered promising candidates for solar water splitting. Amongst various heterostructure systems, combinations of copper and zinc have been advantageous for constructing efficient band potential energy systems. In this work, Cu_xZn_(1-x)S composite photocatalysts were solvothermally prepared with various copper contents. The morphology of the Cu_xZn_(1-x)S photocatalysts was examined using scanning electron microscopy, and the crystalline structures were established with an X-ray diffractometer. Atomic analyses of the surface components of the photocatalysts were performed using X-ray photoelectron spectroscopy. UV-Vis spectroscopy and photoluminescence spectroscopy were also used to examine the efficiency of the photocatalysts' light responses. Brunauer Emmett Teller analyses were employed to characterize the surface area and pore volume of the photocatalysts. Among the various Cu_xZn_(1-x)S compositions, the highest H_2 production rate was determined to be 1122 umol g~(-1) h~(-1) from the Cu_(0.03)Zn_(0.97)S photocatalyst. This highest H_2 production rate is strongly related to the observed efficient light absorption, and its influence on charge generation. The improvement is mainly attributed to the optimized charge separation and utilization, high visible light absorption, and high surface area of the photocatalyst.