Cu(2)In alloy-embedded ZrO(2) catalysts for efficient CO(2) hydrogenation to methanol: promotion of plasma modification

Cu(1)In(2)Zr(4)-O-C catalysts with Cu(2)In alloy structure were prepared by using the sol–gel method. Cu(1)In(2)Zr(4)-O-PC and Cu(1)In(2)Zr(4)-O-CP catalysts were obtained from plasma-modified Cu(1)In(2)Zr(4)-O-C before and after calcination, respectively. Under the conditions of reaction temperature 270°C, reaction pressure 2 MPa, CO(2)/H(2) = 1/3, and GHSV = 12,000 mL/(g h), Cu(1)In(2)Zr(4)-O-PC catalyst has a high CO(2) conversion of 13.3%, methanol selectivity of 74.3%, and CH(3)OH space-time yield of 3.26 mmol/gcat/h. The characterization results of X-ray diffraction (XRD), scanning electron microscopy (SEM), and temperature-programmed reduction chemisorption (H(2)-TPR) showed that the plasma-modified catalyst had a low crystallinity, small particle size, good dispersion, and excellent reduction performance, leading to a better activity and selectivity. Through plasma modification, the strong interaction between Cu and In in Cu(1)In(2)Zr(4)-O-CP catalyst, the shift of Cu 2p orbital binding energy to a lower position, and the decrease in reduction temperature all indicate that the reduction ability of Cu(1)In(2)Zr(4)-O-CP catalyst is enhanced, and the CO(2) hydrogenation activity is improved.