The role of Cu1–O3 species in single-atom Cu/ZrO2 catalyst for CO2 hydrogenation

Abstract

Cu-based catalysts have attracted much interest in CO 2 hydrogenation to methanol because of their high activity. However, the effect of interface, coordination structure, particle size and other underlying factors existed in heterogeneous catalysts render to complex active sites on its surface, therefore it is di cult to study the real active sites for methanol synthesis. Here, we report a novel Cu-based catalyst with isolated Cu active sites (Cu 1 -O 3 units) for highly selective hydrogenating CO 2 to methanol at low temperature (100% selectivity for methanol at 180 o C). Experimental and theoretical results reveal that the single-atom Cu-Zr catalyst with Cu 1 -O 3 units is only contributed to synthesize methanol at 180 o C, but the Cu clusters or nanoparticles with Cu-Cu or Cu-O-Cu active sites will promote the process of reverse water gas shift (RWGS) side reaction to form undesirable byproducts CO. Furthermore, the Cu 1 -O 3 units with tetrahedral structure could gradually migrate to the catalyst surface for accelerating CO 2 hydrogenation reaction during catalytic process. The high activity isolated Cu-based catalyst with legible structure will be helpful to understand the real active sites of Cu-based catalysts for methanol synthesis from CO 2 hydrogenation, thereby guiding further design the Cu catalyst with high performance to meet the industrial demand, at the same time as extending the horizontal of single atom catalyst for application in the thermal catalytic process of CO 2 hydrogenation.

CO2Hydrogenation over Copper/ZnO Single‐Atom Catalysts: Water‐Promoted Transient Synthesis of Methanol

“…%, both conversion and methanol selectivity continuously dropped to 0.7 % and 90.8 %, respectively, after switching to CO 2 /H 2 /H 2 O for 1 h (Figure 2b and Figure S17b). It is worth noting that all the conversions were below 5 %, enabling the measurements in the kinetic regime typically with differential conversions (<5 %) which avoid limitations of heat and mass transfer [21, 24] . This point was verified by the experiments of varying flow rates and particle sizes.…”

“…It is worth noting that all the conversions were below 5 %, enabling the measurements in the kinetic regime typically with differential conversions (< 5 %) which avoid limitations of heat and mass transfer. [21,24] This point was verified by the experiments of varying flow rates and particle sizes. As shown in Figure S18, the reaction rate was independent of flow rates or particle sizes in a certain range, indicating that the reaction kinetics was not determined by external or internal diffusion.…”

“…Cu-based single-atom catalysts have been generally applied to simplify the commercial Cu/ZnO/Al 2 O 3 to investigate the intrinsic catalytic mechanism. [21] To fabricate Cu-based single-atom catalysts, we first synthesized ZnO supports via a hydrothermal method. [22] The ZnO supports had an average diameter of 41 nm in the hexagonal phase (JCPDS#36-1451) (Figure S1).…”

Heterogenous Cu@ZrO2 nanofibers enable efficient electrocatalytic nitrate reduction to ammonia under ambient conditions

“…13 In addition, the optimization of ZrO 2 loading and doping could regulate the electronic structure of the substrate surface and further improve the electrocatalytic performance of the target product. 14,15 Therefore, loading and doping on the substrate surface are potential ways to further exploit the advantages of catalysts.…”

“…(e) NH 3 yield and FE for 8 consecutive cycles of CLZ in 0.1 M KOH + 0.1 M NaNO 3 electrolyte. (f) 1H NMR spectra of the electrolyte after NO 3 RR using15 NO 3 À and 14 NO 3 À…”