CuO/ZnO/Al₂O₃ Catalyst Prepared by Mechanical-Force-Driven Solid-State Ion Exchange and Its Excellent Catalytic Activity under Internal Cooling Condition

Abstract

CuO/ZnO/Al2O3 catalysts were prepared by a mechanical-force-driven solid-state ion-exchange method, and their catalytic performance for methanol synthesis was investigated in a manufactured reactor with an internal cooling system. With the increasing of milling speed during ball-milling, the ion exchange between Cu2+ and Zn2+ in catalyst precursors is enhanced. After calcination, CuO nanoparticles are neighboring to ZnO nanoparticles and ZnO nanoparticles serve as spacers to prevent the agglomeration of CuO nanoparticles, leading to a cross-distribution of CuO and ZnO in catalysts. The as-prepared catalysts exhibit excellent catalytic activities, and the highest CO2 conversion and CH3OH yield at 240 °C and 4 MPa can reach 59.5% and 43.7%, respectively. The extraordinary catalytic performance can be attributed to both the cross-distribution of CuO and ZnO nanoparticles caused by solid-state ion exchange and the promotion of reversible CO2 hydrogenation reaction toward methanol synthesis by the internal cooling system.

Advances in the Design of Heterogeneous Catalysts and Thermocatalytic Processes for CO2 Utilization

“…113,[121][122][123][124][125][126][127][128][129][130][131][132][133] For example, Cu has been reported to strongly interact with ZrO2, leading to more dispersed NPs and enhanced catalyst stability. 134 It was also observed that the Cu-ZrO2 interface was more active than pure Cu surface due to formation of oxygen vacancies by ZrO2. 93,113,135 Along this line, Tada and coworkers studied the formation mechanism of specific active Cu sites on ZrO2 samples of different phases (such as amorphous, tetragonal and monoclinic).…”

CO2 Hydrogenation to Methanol by a Liquid-Phase Process with Alcoholic Solvents: A Techno-Economic Analysis

“…The beneficial effect of the phase distribution in the liquid-phase reactor to the equilibrium conversion level, found in the present process modelling work, should also be experimentally verified and further investigated. Another approach to increase the equilibrium conversion and reaction rate could be provided by the adsorption of water from the reaction mixture [53] or by in situ condensation of water and methanol [54]. Additional costs to the liquid-phase process were caused by the loss of solvent.…”

Microwave, Ultrasound, and Mechanochemistry: Unconventional Tools that Are Used to Obtain “Smart” Catalysts for CO2 Hydrogenation

“…To overcome such problem, very recently a new mechanical-force-driven, solid-state ion-exchange procedure has been refined [129]. It was found that the mutual substitution between Cu 2+ and Zn 2+ was improved with increasing mechanical ball-milling speed from 200 to 400 rpm, leading to significant enhancement of the catalytic activity.…”

“…Such peaks become broader and at the same time decrease in intensity upon the increase of the milling speed, indicating a decrease in crystallinity and crystal size. The absence of the peaks related to the presence of the Al 2 O 3 phase was explained by the alumina change into an amorphous state after ball-milling [126,129].…”