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

[Display omitted] •Photo-thermal-magnetic three-field coupling for enhanced CO2 photo-reduction.•Nickel foam was used as nickel source and catalyst support.•0.01 wt% Cu/Cu2O/HNF exhibited the best catalytic activity and CH4 selectivity.•The heat of the reaction system came from magnetic-thermal and photo-thermal effects. 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.