Highly Efficient Photothermal Reduction of CO₂ on Pd₂Cu Dispersed TiO₂ Photocatalyst and Operando DRIFT Spectroscopic Analysis of Reactive Intermediates

Abstract

The photocatalytic conversion of CO2 to fuels using solar energy presents meaningful potential in the mitigation of global warming, solar energy conversion, and fuel production. Photothermal catalysis is one promising approach to convert chemically inert CO2 into value-added chemicals. Herein, we report the selective hydrogenation of CO2 to ethanol by Pd2Cu alloy dispersed TiO2 (P25) photocatalyst. Under UV-Vis irradiation, the Pd2Cu/P25 showed an efficient CO2 reduction photothermally at 150 °C with an ethanol production rate of 4.1 mmol g−1 h−1. Operando diffuse reflectance infrared Fourier transform (DRIFT) absorption studies were used to trace the reactive intermediates involved in CO2 hydrogenation in detail. Overall, the Cu provides the active sites for CO2 adsorption and Pd involves the oxidation of H2 molecule generated from P25 and C–C bond formation.

Keywords

• photothermal reactor
• CO₂ reduction
• photocatalytic H₂O oxidation
• DRIFT
• alloy