Efficient photocatalysts of a tetraphenylporphyrin/P25 hybrid for visible-light photoreduction of CO2

Abstract

Photocatalytic conversion of CO₂ to applicable organic products using solar energy has attracted increasing attention for solving the universal problems of both global warming and energy shortage. In this paper, tetraphenylporphyrin (TPP) was anchored onto the surface of titanium dioxide P25 by a simple solution impregnation method. The ingenious hybrid possesses the advantages of good visible light absorption ability and excellent photocatalytic performance for CO₂ reduction. The introduction of TPP not only expands the spectral response range and promotes the generation of light-induced electron–hole pairs, but also facilitates the interfacial charge migration and separation and inhibits the recombination of photoinduced carriers, which favors the conversion of CO₂ molecules under visible-light. The optimized TPP/P25 heterogeneous catalysts show excellent activity for CO₂ reduction, with a CO yield of 171.9 μmol g⁻¹ h⁻¹ and a CH₄ yield of 6.3 μmol g⁻¹ h⁻¹. A rational mechanism responsible for its enhanced CO₂ photoreduction was also proposed.