Highly dispersed metal doping to ZnZr oxide catalyst for CO2 hydrogenation to methanol: Insight into hydrogen spillover

Metallic oxide based catalysts have received much attention in CO2 hydrogenation to methanol because of their high methanol selectivity and long-term stability. But the relatively weak hydrogenation ability leads to low methanol activity. Here, we introduce a small amount of Cu (molar fraction < 2%) into ZnZrOx to form ternary metal oxide solid solution catalysts (x% CuZnZr) to promote methanol production. The optimized 0.5% CuZnZr catalyst performs CO2 conversion of 9.5% and methanol yield of 7.2%, both of which are about 4 times that of ZnZr catalyst at comparable methanol selectivity (76% versus 80%) at 290 degrees C. Chemisorption and in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) analyses reveal that the enhanced activity is attributed to the improved hydrogenation capacity and accelerated transformation of HCOO* to CH3O* caused by hydrogen spillover from well dispersed Cu. This can also be applied to trace amount of Pd or Pt doping to ZnZrOx. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

The addition of a small amount of Cu into ZnZrOx can enhance the efficiency of CO2 hydrogenation to methanol, with the optimized catalyst showing higher CO2 conversion and methanol yield at comparable methanol selectivity. This improvement is attributed to the enhanced hydrogenation capacity and accelerated transformation of key intermediates caused by hydrogen spillover from well dispersed Cu.