Cu Nanoparticles Inlaid Mesoporous Al₂O₃ As a High-Performance Bifunctional Catalyst for Ethanol Synthesis via Dimethyl Oxalate Hydrogenation

Abstract

Ethanol synthesis from syngas via dimethyl oxalate (DMO) hydrogenation is of crucial importance for environment- and energy-related applications. Herein, we designed the bifunctional Cu nanoparticle (NP) inlaid mesoporous Al2O3 catalyst and first applied it to ethanol synthesis with high efficiency. The catalyst was made based on the spatial restriction strategy by pinning the Cu NPs on mesoporous Al2O3 to conquer the sintering problem and facilitate the stability (>200 h at 270 °C), which has potential values in high-temperature and exothermic reactions. The plentiful pores, highly exposed and properly assembled Cu-acid sites, furnished the catalyst with high ethanol yield (∼94.9%). A structure-sensitive behavior that the intrinsic activity increases with the decreasing NP size was discussed. It was attributed to the change in metal–acid interfacial sites, morphology, and electronic structure and balance of surface Cu0–Cu+ species. The mechanism for DMO hydrogenation to ethanol involving activation of CO, C–O, and O–H bands was also proposed. As cleavage of these bonds is a versatile tool to utilize bioderived molecules (e.g., polyols), the bifunctional catalysts can also be applied to hydrogenolysis of C–O bonds or etherification of O–H groups to produce various chemicals.

Synthesis of Tetrahydropyran from Tetrahydrofurfuryl Alcohol over Cu–Zno/Al2O3 under a Gaseous-Phase Condition

“…The generation of medium acid sites may be due to the interaction between Cu-ZnO and γ-Al2O3 during the preparation process. The amount of strong acid sites increased with the increase in γ-Al2O3, in good agreement with previous reports [39]. …”

Hydrogenation of biomass-derived compounds containing a carbonyl group over a copper-based nanocatalyst: Insight into the origin and influence of surface oxygen vacancies

“…Further, a broad and asymmetric Auger kinetic energy peak is observed from the Cu LMM XAES, indicative of the coexistence of Cu 0 and Cu + species in reduced CuMn-x samples (Fig. S8) [61], because of strong interaction between Cu species and supports [62]. This interaction, which originates from the homogeneous distributions of metal cations in the brucite-like layers of LDH precursors, can give rise to Cu + -O-M-like (M = Al or Mn) structures after reduction.…”

Rational design of Ni-based catalysts derived from hydrotalcite for selective hydrogenation of 5-hydroxymethylfurfural

“…The results showed a decrease of surface metallic Ni concentrations and an increase of amounts of surface acid sites with the elevation of calcination temperature. 32 The Raman and IR results both suggested that the NiO was strongly interacting with the emerging alumina support upon hydrotalcite decomposition and the strong interactions were greatly enhanced after calcination. The peaks of NiO intensified slightly with the increase of calcination temperature, indicating a slow particle growth of NiO.…”