Indexed by:期刊论文

Date of Publication:2018-01-01

Journal:ACS CATALYSIS

Included Journals:SCIE、EI

Volume:8

Issue:1

Page Number:90-100

ISSN No.:2155-5435

Key Words:CO2 conversion; nonthermal plasmas; plasma catalysis; CO2 hydrogenation; methanol synthesis; ambient conditions; synergistic effect

Abstract:CO2 hydrogenation to methanol is a promising process for CO2 conversion and utilization. Despite a well-developed route for CO hydrogenation to methanol, the use of CO2 as a feedstock for methanol synthesis remains underexplored, and one of its major challenges is high reaction pressure (usually 30-300 atm). In this work, atmospheric pressure and room temperature (similar to 30 degrees C) synthesis of methanol from CO2 and H-2 has been successfully achieved using a dielectric barrier discharge (DBD) with and without a catalyst. The methanol production was strongly dependent on the plasma reactor setup; the DBD reactor with a special water-electrode design showed the highest reaction performance in terms of the conversion of CO2 and methanol yield. The combination of the plasma with Cu/gamma-Al2O3 or Pt/gamma-Al2O3 catalyst significantly enhanced the CO2 conversion and methanol yield compared to the plasma hydrogenation of CO2 without a catalyst. The maximum methanol yield of 11.3% and methanol selectivity of 53.7% were achieved over the Cu/gamma-Al2O3 catalyst with a CO2 conversion of 21.2% in the plasma process, while no reaction occurred at ambient conditions without using plasma. The possible reaction mechanisms in the plasma CO2 hydrogenation to CH3OH with and without a catalyst were proposed by combined means of electrical and optical diagnostics, product analysis, catalyst characterization, and plasma kinetic modeling. These results have successfully demonstrated that this unique plasma process offers a promising solution for lowering the kinetic barrier of catalytic CO2 hydrogenation to methanol instead of using traditional approaches (e.g., high reaction temperature and high-pressure process), and has great potential to deliver a step-change in future CO2 conversion and utilization.