Efficient Thermal Management with Selective Metamaterial Absorber for Boosting Photothermal CO2 Hydrogenation under Sunlight

Abstract

Photothermal catalytic CO₂ hydrogenation is a prospective strategy to simultaneously reduce CO₂ emission and generate value-added fuels. However, the demand of extremely intense light hinders its development in practical applications. Herein, this work reports the novel design of Ni-based selective metamaterial absorber and employs it as the photothermal catalyst for CO₂ hydrogenation. The selective absorption property reduces the heat loss caused by radiation while possessing effectively solar absorption, thus substantially increasing local photothermal temperature. Notably, the enhancement of local electric field by plasmon resonance promotes the adsorption and activation of reactants. Moreover, benefiting from the ingenious morphology that Ni nanoparticles (NPs) are encapsulated by SiO₂ matrix through co-sputtering, the greatly improved dispersion of Ni NPs enables enhancing the contact with reaction gas and preventing the agglomeration. Consequently, the catalyst exhibits an unprecedented CO₂ conversion rate of 516.9 mmol g_cat ^-1 h^-1 under 0.8 W cm^-2 irradiation, with near 90% CO selectivity and high stability. Significantly, this designed photothermal catalyst demonstrates the great potential in practical applications under sunlight. This work provides new sights for designing high-performance photothermal catalysts by thermal management.

Keywords: CO2 hydrogenation; photothermal catalysis; selective metamaterial absorbers; solar energy utilization; thermal management.