Effect of the Synthesis Method on Physicochemical Properties and Performance of Cu/ZnO/Nb₂O₅ Catalysts for CO₂ Hydrogenation to Methanol

Abstract

In the present work, we investigated the influence of the synthesis method of Nb-promoted Cu/Zn materials on their physicochemical and catalytic properties. Cu/ZnO/Nb2O5 was prepared by coprecipitation (CP), deposition–precipitation (DP), wet impregnation (WI), and incipient wetness impregnation (IW) methods. The physicochemical properties of these materials were investigated by XRF, XRD, N2 physisorption, SEM, TEM, TEM–EDS, H2-TPR, N2O passivation, and CO2-TPD. According to the results, it was found that when Nb was coprecipitated with copper and zinc (Cu/Zn/Nb–CP) there was the formation of a material with smaller particles, larger specific surface area, larger metallic copper area, and higher basicity than those of the other investigated materials. In the CO2 hydrogenation at 200 °C, this catalyst exhibited the best performance in terms of activity (X CO2 = 5.2%) and selectivity to methanol (S MeOH = 70.2%). Further characterization, via in situ DRIFTS, revealed that the formation of methanol over Cu/Zn/Nb–CP occurs via “RWGS + CO-Hydro” and “formate” pathways.

A generalized machine learning framework to predict the space-time yield of methanol from thermocatalytic CO2 hydrogenation

“…Other techniques reported included flame spray pyrolysis, solvothermal, sol-gel, microwave-assisted synthesis to mention a few and other variants of impregnation, all of which were collectively classified as others in the dataset. Although the simplicity and effectivity of the preparation method seemed to influence the choice of preparation methods, comparative evaluation of synthesis methods on the performance of specific catalyst have also been reported [52,53].…”

Ethanol formation from CO2 hydrogenation at atmospheric pressure using Cu catalysts: Water as a key component

“…8, taking into account the catalytic results, thermodynamic discussion, and the DRIFTS tests. It is important to mention that CO 2 can adsorb in different ways depending on the catalyst and reaction conditions [67][68][69]. *HCOO is considered the main intermediate for methanol synthesis (called formate pathway) and it is believed that CO is not formed from this pathway [70].…”

“…Effective Cu-based catalysts have been used for CO 2 hydrogenation, such as modified industrial Cu/ZnO/Al 2 O 3 [1,2], Cu/ZnO/M (M= Zr [3][4][5], Ce [6,7], Ti [8][9][10], Ga [11][12][13], Nb [14], and others [15,16]), and Pd-Cu [17,18], but mainly C 1 compounds (CO, CH 4 , and methanol) are reported as products. Such an approach has already been applied for methanol synthesis on a large scale.…”

Recent Understanding of Water‐Assisted CO2 Hydrogenation to Alcohols

“…Various catalyst types, such as those based on both noble, [3] and nonnoble transition metals [4] have emerged as promising contenders. Many properties like catalyst structure, [5,6] promoters, [7][8][9][10][11] supports, [12][13][14][15] and precursor materials [16,17] have been shown to play essential roles in the reaction mechanism and catalytic performance.…”