Photothermal Coupling Effect Boosts the Conversion of CO₂ to Solar Fuel Over Pt/ZnO Photocatalyst in a Concentrated Solar Reactor

Abstract

The low photocatalytic reaction rate and energy conversion efficiency are the key factors restricting the direct solar-driven CO2 production of solar fuels. Here, the photothermal coupling system based on the concentrated irradiation of Fresnel lenses was designed for the light-driven CO2 conversion process. Under the condition of concentrated irradiation, the solar energy to chemical energy conversion efficiency increased from 0.012 to 0.264%, while the CO yield increased 120 times (from 0.96 to 115.32 μmol g–1 h–1) over the Pt/ZnO photocatalyst, with significant performance resulting from the increase of carrier concentration and Fermi level and the decrease of apparent activation energy. Pt nanoparticles improved the light absorption performance and surface temperature of the photocatalyst under concentrated light irradiation. Photoelectrochemical measurements, evaluation of the photocatalytic performance at different wavelengths, and apparent activation energy calculations revealed that concentrated light irradiation can be an effective way to reduce apparent activation energy (from 48.19 to 37.23 kJ/mol). This provided a potentially feasible method for efficient and green utilization of CO2 driven by solar energy.

Concentrated solar CO2 reduction in H2O vapour with >1% energy conversion efficiency

“…The remarkably strong m-CO 3 2− peaks indicate that CO 2 is adsorbed on the lattice O of CeO 2 instead of on Ni. The production of –CH 2 O, –CH 3 O and –CH 3 intermediates confirms the migration of multiple photo-generated electrons and, notably, the production of CH 4 32 , 33 . The adsorption bands at 3725, 3677, 3624 and 3594 cm −1 are attributed to physical adsorption via hydrogen-bound OH groups and H 2 O stretching vibrations (Supplementary Fig.…”