Sputtered Cu-ZnO/γ-Al₂O₃ Bifunctional Catalyst with Ultra-Low Cu Content Boosting Dimethyl Ether Steam Reforming and Inhibiting Side Reactions

Abstract

Dimethyl ether steam reforming (DME SR) is one of attractive technologies to online provide H 2 for fuel cells in vehicles. Herein, we adopt a novel sputtering method to prepare a Cu-ZnO/γ-Al 2 O 3 (CuZn− S) bifunctional catalyst with only 2.9 wt % Cu loading. The interaction between Cu and ZnO suppresses the thermal aggregation of Cu nanoparticles in DME SR. The Cu nanoparticles (methanol steam reforming sites) are highly and homogeneously dispersed and anchored on the external surface of γ-Al 2 O 3 (DME hydrolysis sites). It significantly improves the utilization efficiency of the Cu species and the mass transfer, thereby achieving high catalytic performance for DME SR. Its reaction rate per unit mass of Cu is 50 times to that of the CuZnAlO/γ-Al 2 O 3 catalyst at 300 °C. In addition, this unique structure inhibits the side reactions of methanol direct decomposition and reverse water gas shift to suppress CO production.

Theoretical study on copper adsorption on ZnO surfaces for CO2 hydrogenation to methanol

“…Previous studies from literature have suggested that there might be a correlation between the adsorption energy (i.e., stability of the system) and the amount of charge exchanged [34][35][36][37][38]. This is because the amount of charge exchanged affects the electrostatic interactions between the adsorbate and the surface.…”

“…To address these issues, γ-Al2O3 was found as a promising replacement for Al2O3 in the support of Cu-based catalysts. The use of γ-Al2O3 help improve the stability and longevity of the catalyst, leading to better overall performance in methanol synthesis [35][36][37]. Optimizing the performance of Cu/ZnO based catalyst hinges on a thorough understanding of the interaction between Cu and ZnO at the atomic level.…”

Theoretical Study on Copper Adsorption on ZnO Surfaces

“…The resulting scattering is defined as partial differential scattering cross section in which the number of neutrons scattered 𝑑 2 σ per second into the small solid angle ∆Ω with final energy between E ' and (E ' + dE ' ) (equation 2). The partial differen-tial scattering cross section is directly proportional to the scattering function S(Q,E) [30,36].…”