Mesoporous In(OH)3 for photoreduction of CO2 into renewable hydrocarbon fuels

Indium hydroxide (In(OH)3) with mesoporous structure has been synthesized via a sol–gel hydrothermal treatment. The phase compositions, optical properties, and morphologies of the photocatalysts were systematically investigated via powder X-ray diffraction, UV–visible absorption spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy, chemisorption analyzer and transmission electron microscopy. The theoretical calculation based on density functional theory demonstrated that the potentials of valence band and conduction band of In(OH)3 are both suitable for CO2 photoreduction. The photocatalytic efficiencies of the samples were characterized by testing the photoreduction of CO2 to CH4 under full-arc Xe lamp irradiation. The sample modified with mesoporous structure is about 20 times higher in efficiency than that of sample without mesoporous structure, which is attributed to the outstanding structure characteristics in higher surface area and strong adsorption of the mesoporous structure.