Catalytic Conversion of CO2 to Value-Added Products under Mild Conditions

The catalytic synthesis of multi-carbon alcohols (MCA, CnH2n+1OH, n >= 3) and higher hydrocarbons from CO2 and H-2 under low or even ambient temperature are realized for the first time over a prepared bimetallic catalyst composed of nanoparticles of Pt and Ru supported on Fe3O4 (Ru-Pt/Fe3O4). At 40 degrees C, the selectivity for alcohols, MCA, and higher hydrocarbons reached 77.1 %, 4.5 %, and 19.5 %, respectively, while that for methane was only 3.4 % (carbon based). As revealed by isotope tracer experiments using O-18 labeled water, in the hydrogenation of CO2 over Ru-Pt/Fe3O4, MCA could form by catalytic hydrolysis of alkyl, a novel reaction pathway enabling the formation of MCA at low temperature, which is different from the previously reported one based on CO insertion at high temperature. It was discovered that in Ru-Pt/Fe3O4, both Ru and Pt nanoparticles played catalytic roles in the reduction of CO2 to CHx species and the carbon-carbon coupling reaction to form alkyl, while the catalytic hydrolysis of formed long-chain alkyl occurred on Pt nanoparticles.