Enhancement of Photocatalytic Water Splitting Rate via Rayleigh Convection

Seiichi Deguchi, Ben Kariya, Norifumi Isu, Shoji Shimasaki, Haruna Banno, Saeko Miwa, Keisuke Sawada, Junki Tsuge, Shoichiro Imaizumi, Hidenori Kato, Kyota Tokutake

Department of Energy Engineering and Science, Nagoya University, Nagoya, Japan.
Kitchen and Bathroom Technology Research Institute, LIXIL Corporation, Tokoname, Japan.
School of Chemical Engineering, Purdue University, West Lafayette, USA.

DOI: 10.4236/gsc.2014.42012                

Abstract

In order to enhance photocatalytic water splitting rates with Pt/TiO₂ powder, sufficient agitation of the biphasic medium is required to switch surficial reactions to volumetric reactions. Additionally, agitation is conducive to higher diffusion rates of the generated hydrogen and co-produced oxygen, hindering their ability to re-couple to water on Pt loaded to TiO₂ powder. In order to create agitation without consuming any electricity, a novel technique utilizing Rayleigh convection was applied, and its ability to enhance photocatalytic water splitting rates was evaluated. Higher Rayleigh convective flow rates resulted in higher photocatalytic water splitting rates. Utilization of Rayleigh convection approximately doubled the photocatalytic water splitting rates, despite relatively low convective flow velocities (obtained through simple thermo-hydrodynamic simulations). The rate enhancement achieved through Rayleigh convection is a result of its ability to disperse the ultrafine Pt/TiO₂ particles throughout the whole medium, leading to volumetric reactions.

Keywords

Photocatalytic Water Splitting, Pt/TiO2 Powder, Rate Enhancement, Volumetric Reaction, Thermal Treatment, Rayleigh Convection, Thermo-Hydrodynamic Simulation

Conflicts of Interest

The authors declare no conflicts of interest.

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