Construction of a Photo-thermal-magnetic coupling reaction system for enhanced CO₂ reduction to CH₄

Aiming at the bottleneck of thermodynamics, kinetics and reaction systems in photothermal catalytic CO₂ reduction conversion, a three-field coupling method based on the efficient utilization of solar energy and the application of a photo-thermal-magnetic three-field was proposed to achieve efficient and highly selective CO₂ conversion. The composite monolithic catalyst with three field response functions and multiple active reaction interfaces was prepared by using photoactive copper supported by nickel foam. The effect of an external alternating magnetic field on photocatalytic CO₂ reduction was studied using a range between 0.005 and 0.1 wt% Cu/Cu₂O/Ni(OH)₂/NF as catalysts. The results showed that 0.01 wt% Cu/Cu₂O/Ni(OH)₂/NF exhibited the best catalytic activity and CH₄ selectivity under alternating magnetic field enhanced photocatalysis. The main products were CO (6.76 μmol g⁻¹) and CH₄ (167 μmol g⁻¹). The selectivity of CH₄ was 96.1%. The yields of CH₄ using this method were 11 and 6 times higher than the yields obtained with photocatalysis (14.58 μmol g⁻¹) and magnetic-thermal catalysis (26.75 μmol g⁻¹), respectively. According to the analysis of temperature measurements and electrochemical measurements, the surface temperature of the three-field coupled catalyst reaches about 230 °C. Applying an alternating magnetic field can effectively reduce the recombination of photogenerated electron holes. Alternating magnetic field enhanced photocatalytic CO₂ reduction conversion provides a new and promising method for the efficient conversion and utilization of solar energy.