Continuous Photocatalysis Based on Layer-by-Layer Assembly of Separation-Free TiO2/Reduced Graphene Oxide Film Catalysts with Increased Charge Transfer and Active Site: Continuous Photocatalysis Based on Layer-by-Layer Assembly of Separation-Free TiO2/Reduced Graphene Oxide Film Catalysts with Increased Charge Transfe

Although photodegradation is the most widely studied method for the purification of water, the challenges for the post-separation of catalysts from water make the technique unsuitable for practical applications. In this study, separation-free TiO2/reduced graphene oxide (rGO) multilayer films were first prepared through layer-by-layer (LbL) assembly of TiO2 and graphene oxide (GO) on quartz slides, followed by a reduction of the assembled GO to rGO. For a proof-of-concept demonstration of novel continuous photocatalysis with potential for scaled-up production, these quartz slides with TiO2/rGO film catalysts were further assembled into slide arrays in a home-made rectangular quartz reactor and a model pollutant Rhodamine B (RhB) solution was circularly pumped over the slide surface under UV irradiation. It was found that the as-prepared TiO2/rGO film catalysts show excellent enhanced photocatalytic activity for this pumping-based continuous photocatalysis, with a photodegradation rate constant of 2.6 x 10(-2) min(-1) exceeding the corresponding TiO2/GO and TiO2 (TiO2/PSS) samples by a factor of 11.3 and 13, respectively. The enhanced performance is attributed to the formation of Ti-O-C bonds in film catalysts bridging TiO2 and rGO to enable efficient charge separation and transfer, the Ti-O-C bond bridged electron transfer leading to increase in O-center dot(2)- active sites on the rGO surface, and the porous-like multilayer structure. The recycling experiments showed the film catalysts are stable and could be reused with the same efficiency for at least 8 cycles.