Synthesis and Catalytic Performance of Graphene Modified CuO-ZnO-Al2O3 for CO2 Hydrogenation to Methanol

CuO-ZnO-Al2O3 and graphene nanosheet (GNS) were synthesized by coprecipitation route and reduction of exfoliated graphite oxides method, respectively. GNS modified CuO-ZnO-Al2O3 nanocomposites were synthesized by high energy ball milling method. The structure, morphology, and character of the synthesized materials were studied by BET, XRD, TEM, and H-2-TPR. It was found that by high energy ball milling method the CuO-ZnO-Al2O3 nanoparticles were uniformly dispersed on GNS surfaces. The catalytic performance for the methanol synthesis from CO2 hydrogenation was also tested. It was shown experimentally that appropriate incorporation of GNS into the CuO-ZnO-Al2O3 could significantly increase the catalyst activity for methanol synthesis. The 10 wt.% GNS modified CuO-ZnO-Al2O3 catalyst gave a methanol space time yield (STY) of 92.5% higher than that on the CuO-ZnO-Al2O3 catalyst without GNS. The improved catalytic performance was attributed to the excellent promotion of GNS to dispersion of CuO and ZnO particles.