Catalytic reduction of carbon dioxide by nickel-based catalyst under atmospheric pressure

• Ni–P/Al2O3 proved to be effective for catalyzing CO2 reduction.
• A new method of CO2 resource utilization under atmospheric pressure was developed.
• The reaction mechanism was proposed according to the characterizations of products.

To develop a new method of CO2 resource utilization, the screening tests of catalysts were carried out, and Ni–P/Al2O3 was established as the most suitable composite catalyst for CO2 catalytic reduction. By optimizing, the main preparation conditions of Ni–P/Al2O3 were obtained with Ni/P of 1:1, impregnation time of 12 h and calcination temperature of 550 °C. For CO2 reduction based on Ni–P/Al2O3 catalysis, the optimal experimental conditions were determined as Ni–P/Al2O3 content of 1%, sodium borohydride (NaBH4) concentration of 0.175 mol L−1, reaction temperature of 55 °C, pH of 8.0, ethanol concentration of 90%, and residence time of 15 s. And 41.37% of the average efficiency of CO2 reduction was reached. Compared with the results of non-catalytic conditions, the NaBH4 dosage was reduced by 60.14%, which indicated the excellent catalytic ability of Ni–P/Al2O3 on CO2 reduction, from which, the innovative method of the catalytic reduction of carbon dioxide (CO2) by NaBH4 under atmospheric pressure and moderate temperature was proposed. Based on the analyses of Scanning Electron Microscope, X-ray Powder Diffraction and Ion Chromatograph, the catalytic reduction mechanism of CO2 by Ni–P/Al2O3 was revealed.