Synergistic effect of Cu+ single atoms and Cu nanoparticles supported on alumina boosting water-gas shift reaction

The water-gas shift reaction (WGSR) is an important industrial process for H2 production. Here, we rationally construct alumina supported dual-site copper catalysts, i.e. Cu+ single atoms (Cu1+) surrounding Cu nanoparticles (CuNP0), for WGSR. Our findings show that CO is tightly adsorbed on surface-enriched Cu1+ sites to inhibit competitive adsorption with H2O on CuNP0 sites. The number of adsorbed CO is two orders of magnitude higher than that on conventional Cu-based catalysts. It significantly increases surface CO concentration, and forms a unique structure of CuNP0 “islands” immerged in CO “pool”. Benefiting from synergy of Cu1+ and CuNP0 sites, the catalyst with 12% Cu loading exhibits extraordinary and robust catalytic activity, compared to benchmark Cu-Zn-Al catalyst, especially at low temperatures, e.g. 200 °C. The catalyst design strategy and facile synthesis methodology employed in this work could be potentially applied in other related industrial reactions.