Electro-assisted photothermal synergy for removal of volatile organic compounds over Au single atoms anchored TiO2 nanotubes

Abstract

Gas-phase photoelectrocatalysis (GPEC) systems for treating gas pollution may lead to a Joule-heat effect and form photothermal synergy under an external bias voltage. However, such a synergistic effect and mechanism remain unclear. Herein, a electro-assisted photothermal synergistic removal of VOCs by defective TiO2 nanotube array decorated with atomically dispersed Au species was chosen as a prototypical illustration. By introducing single Au atoms, the carrier concentration and mobility of the catalytically active layer, i.e., TiO2 nanotube arrays anchored with Au single atoms, were substantially increased to the semi-metal level through an electrochemical reduction step and square-wave pulse method for anchoring single atoms. This not only contributes to the photogenerated carrier separation at low external bias but also significantly enhances the Joule heating effect on the catalyst surface. As a result, the catalyst used exhibited an excellent electro-assisted photothermal synergistic effect and outstanding efficiency in toluene removal in the designed tubular reactor. SynopsisA novel electro-assisted photothermal synergy system was constructed, which combines the advantages of gas-phase photoelectrocatalysis and electrothermal catalysis to remove VOCs with high efficiency and low energy consumption.