Gold-nanoparticle-modified TiO2 nanowires for plasmon-enhanced photocatalytic CO2 reduction with H2 under visible light irradiation

Abstract:

Gold-nanoparticles (Au-NPs) incorporated TiO₂-nanowires (TiO₂-NWs) of controlled sizes prepared via hydrothermal and chemical reduction method have been investigated for CO₂ photoreduction with H₂ under visible light irradiations. The nanocatalysts have been characterized by XRD, FESEM, TEM, N₂ adsorption–desorption, XPS, UV–vis and PL spectroscopy. Highly crystalline TiO₂ nanowires of mesoporous structure were obtained in Au-deposited TiO₂ NWs. Au-NPs, uniformly distributed over TiO₂-NWs as Au-metal state, hindered charges recombination rate and increased TiO₂ activity under visible light through plasmon excitation. With the deposition of Au-NPs, the efficiency of CO₂ reduction to CO was greatly enhanced under lower energy visible light irradiations. The maximum CO and CH₃OH yield rate over 0.5 wt.% Au-NPs/TiO₂ NWs reached to 1237 and 12.65 μmole g catal.⁻¹ h⁻¹, respectively. High quantum yield was also observed over Au-NPs/TiO₂ NWs using H₂as reductant. The significantly improved photoactivity was evidently due to efficient electron–hole separation and surface plasmon response of Au-NPs. The reaction-pathway is proposed to provide insights over the mechanism of Au-plasmon-enhanced CO₂ conversion.

1. Muhammad Tahir, Beenish Tahir and Nor Aishah Saidina Amin (2015). Gold-nanoparticle-modified TiO2 nanowires for plasmon-enhanced photocatalytic CO2 reduction with H2 under visible light irradiation,. Applied Surface Science, 356, 1289-1299. DOI: https://doi.org/10.1016/j.apsusc.2015.08.231