Water Denitration over titania-supported Pt and Cu by combined photocatalytic and catalytic process: Implications for hydrogen generation properties in a photocatalytic system

Anca Vasile, Florica Papa, Veronica Bratan, Cornel Munteanu, Mircea Teodorescu, Irina Atkinson, Mihai Anastasescu, Daisuke Kawamoto, Catalin Negrila, Cristian D. Ene, Tanta Spataru and Ioan Balint

The present work provides a new approach to the water denitration process and a facile strategy of catalyst preparation for the efficient hydrogen generation. The main focus of the research reported here was nitrate removal from aqueous solutions and simultaneous hydrogen generation under UV-Vis-light irradiation. This is a very important aspect in case of practical applications, eliminating the external source of hydrogen. Aiming to get a deeper understanding on the role of surface structures (size and shape of nanoparticles) towards the reduction mechanism and to establish basic principles for an efficient process, Pt-Cu/TiO2 and Pt-Cu/TiO2 modified with well-defined Pt nanoparticles were employed. The synthesized materials were characterized using various physicochemical techniques and tested comparatively for: (i) nitrate catalytic reduction by hydrogen (dark reaction) and (ii) nitrate photocatalytic reduction by in-situ generated solar hydrogen. In order to enhance overall denitration reaction by combined photocatalytic and catalytic processes, photo-generated charges and insitu generated H2 as reducing agent were used. Improvement of catalytic performances of nitrate hydrogenation reaction (~100% NO3‾ conversion) related to intimate contact between Pt and Cu was obtained. The in-situ generated H2 by water splitting over the studied catalysts reduces efficiently NO3‾ ions. Enhanced photocatalytic activity toward solar H2 production by deposited well-defined Pt nanoparticles (~10 nm) was achieved. In order to make possible decontamination of polluted waters using in-situ generated H2 under light exposure, the future optimization of such photo-catalytic systems looks promising.

Journal of Environmental Chemical Engineering

10

107129

10.1016/j.jece.2022.107129