Nanoporous Palladium-catalyzed Hydrogenation Of Carbon Dioxide

Carbon dioxide was the most abundant carbon resource in C1 family and had the advantages of cheap, easily obtained, non-toxic, renewable and so on. The study of immobilization and resources for carbon dioxide was one of the most important issues in the world. Among them, the catalyzed hydrogenation of carbon dioxide to formic acid (formate) was one of the effective ways of resource utilization. Formic acid was not only an important organic synthesis material, but also an important liquid hydrogen storage material. Therefore, the development of highly active catalyst for the hydrogenation of carbon dioxide to formates became a hot research topic.For the first time, the nanoporous palladium (PdNPore) catalyst catalyzed hydrogenation of carbon dioxide (CO2) to formic acid (formate) was systematically studied using hydrogen as hydrogen source in the paper. In alkaline aqueous solution, heterolytic cleavage of hydrogen occured on the surface of the nanoporous palladium to form the Pd-H active species followed by the reduction of carbon dioxide to formate.1. Because carbon dioxide as the form of bicarbonate existed in alkaline aqueous solution. So, the hydrogenation of sodium bicarbonate to sodium formate was selected as the example reaction. The influence factors on the hydrogenation of CO2 and bicarbonates to formates were investigated, including catalysts, temperature, pressure, base and base concentration et al. The optimized reaction conditions:nanoporous palladium 2 (5 mmol%) as the catalyst,0.5 M NaHCO3 aqueous solution as the substrate,1 MPa as the pressure of H2, at 80? for 20 h. The highest yield of sodium formate was up to 99%. The selectivity was 100%.2. The studied results showed that the highly homogeneous dispersion of the nano pore structure in the surface of PdNPore was beneficial to the hydrogenation of CO2 to formate. In the reaction, the leaching of PdNPore did not happen. The catalytic activity of PdNPore did not decrease obviously after using three times. The studied results showed that the hydrogenation reaction could be promoted by the aluminium in nanoporous palladium.