Ultrasmall Cu Nanoparticles Supported on Crystalline, Mesoporous ZnO for Selective CO₂ Hydrogenation

Converting CO2 to value-added chemicals, e. g., CH3OH, is highly desirable in terms of the carbon cycling while reducing CO2 emission from fossil fuel combustion. Cu-based nanocatalysts are among the most efficient for selective CO2-to-CH3OH transformation; this conversion, however, suffers from low reactivity especially in the thermodynamically favored low temperature range. We herein report ultrasmall copper (Cu) nanocatalysts supported on crystalline, mesoporous zinc oxide nanoplate (Cu@mZnO) with notable activity and selectivity of CO2-to-CH3OH in the low temperature range of 200-250 degrees C. Cu@mZnO nanoplates are prepared based on the crystal-crystal transition of mixed Cu and Zn basic carbonates to mesoporous metal oxides and subsequent hydrogen reduction. Under the nanoconfinement of mesopores in crystalline ZnO frameworks, ultrasmall Cu nanoparticles with an average diameter of 2.5 nm are produced. Cu@mZnO catalysts have a peak CH3OH formation rate of 1.13 mol h(-1) per 1 kg under ambient pressure at 246 degrees C, about 25 degrees C lower as compared to that of the benchmark catalyst of Cu-Zn-Al oxides. Our new synthetic strategy sheds some valuable insights into the design of porous catalysts for the important conversion of CO2-to-CH3OH.