Photocatalysis combined with membrane technology could offer an enormous potential for\npower generation in a renewable and sustainable way. Herein, we describe the one-step hydrogen\nand oxygen evolution through a photocatalytic membrane reactor. Experimental tests were carried\nout by means of a two-compartment cell in which a modified Nafion membrane separated the\noxygen and hydrogen evolution semi-cells, while iron ions permeating through the membrane\nacted as a redox mediator. Nanosized Au/TiO2 and Au/CeO2 were employed as suspended\nphotocatalysts for hydrogen and oxygen generation, respectively. The influence of initial Fe3+\nion concentration, ranging from 5 to 20 mM, was investigated, and the best results in terms of\nhydrogen and oxygen evolution were registered by working with 5 mM Fe3+. The positive effect of\ngold on the overall water splitting was confirmed by comparing the photocatalytic results obtained\nwith the modified/unmodified titania and ceria. Au-loading played a key role for controlling the\nphotocatalytic activity, and the optimal percentage for hydrogen and oxygen generation was 0.25 wt%.\nUnder irradiation with visible light, hydrogen and oxygen were produced in stoichiometric amounts.\nThe crucial role of the couple Fe3+/Fe2+ and of the membrane on the performance of the overall\nphotocatalytic system was found.
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