Highly Efficient and Selective Photothermal Catalytic CO₂ Reduction to CH₄ Using the CoNi Bimetallic-Modified Gd₂O₃&Co₃O₄ Nanocomposite

With the increase of CO2 in the atmosphere, how to convert CO2 into fuel has become a research hotspot. Photothermal catalysis is a quite promising method to obtain CH4 via the Sabatier reaction. In this context, it is urgent to design efficient catalysts to improve the conversion and selectivity of aqueous CO2 to CH4. In this work, the CoNi/(Gd2O3&Co3O4) nanocomposite was fabricated via calcination and chemical deposition methods. Compared with Gd2O3 and Co3O4, 80%-CoNi/(Gd2O3&Co3O4) shows an enhancement of photothermal catalytic CH4 evolution rate (4.19 mmol g–1 h–1) and high selectivity for CH4 (98.6%). In addition, this sample also possesses outstanding durable and cyclic catalytic stability. Combined with systematic analysis, it was found that the excellent catalytic performance of 80%-CoNi/(Gd2O3&Co3O4) can be attributed to two main reasons: (i) the dual-heterostructure formation of the P–N and Schottky junction endows the catalyst with high charge separation efficiency and (ii) the catalyst presents preeminent CO2 adsorption and redox capacities, which greatly improves its catalytic activity. This study has significant advantages for the resource utilization of CO2 and the sustainable utilization of catalysts.