Improved methanol yield and selectivity from CO2 hydrogenation using a novel Cu-ZnO-ZrO2 catalyst supported on Mg-Al layered double hydroxide (LDH)

Abstract

Methanol synthesis via CO2 hydrogenation is an important part of the strategy for generating clean energy as we attempt to reduce our dependency on fossil fuels. Conventional catalysts for this reaction need improvement in their methanol selectivity. In this work, a layered double hydroxide (Mg-Al LDH) was used as a carrier for Cu-ZnO-ZrO2 to produce a catalyst by co-precipitation. From characterization results, CuO-ZnO-ZrO2 nanoparticles were formed and were uniformly dispersed and attached to the surface of LDH. BET surface area and copper dispersion of the catalysts were significantly improved by 4.3 times and 2.9 times, respectively, compared with a reference catalyst without the support. In a catalytic reaction, the catalyst showed dramatic methanol selectivity of 78.3% at 523 K and 3.0 MPa, which is 14.4% higher than the commercial catalyst measured in this investigation and about 50% higher than conventional copper-based catalysts in literatures. It also showed over twice the space time yield based on active metal sites compared to a commercial catalyst in the temperature range 473 K–573 K. Therefore, the prepared catalyst can be efficiently applied at relatively mild reaction temperatures and pressures.