Influence of Indium as a Promoter on the Stability and Selectivity of the Nanocrystalline Cu/CeO₂ Catalyst for CO₂ Hydrogenation to Methanol

Abstract

Stable catalyst development for CO2 hydrogenation to methanol is a challenge in catalysis. In this study, indium (In)-promoted Cu nanoparticles supported on nanocrystalline CeO2 catalysts were prepared and explored for methanol production from CO2. In-promoted Cu catalysts with ∼1 wt % In loading showed a methanol production rate of 0.016 mol gCu –1 h–1 with 95% methanol selectivity and no loss of activity for 100 h. It is found that the addition of indium remarkably increases Cu dispersion and decreases Cu particle size. In addition led to an increased metal–support interaction, which stabilizes Cu particles against sintering during the reaction, leading to high stability and activity. In addition, density functional theory calculations suggested that the reaction is proceeding via reverse water gas shift (RWGS) mechanism where the presence of In stabilized intermediate species and lowered CO2 activation energy barriers.

Ga-Promoted CuCo-Based Catalysts for Efficient CO2 Hydrogenation to Ethanol: The Key Synergistic Role of Cu-CoGaOx Interfacial Sites

“…Simultaneously, two δ­(CH) and ν as (OCO) bands of formate (HCOO*) species appear at 2877 and 2966 cm –1 , respectively, indicative of the occurrence of the reaction between adsorbed CO 3 2– species and chemisorbed hydrogen atoms formed during the reduction of catalysts . As the temperature is elevated to 150 °C, three new peaks appear at 1062, 1395, and 2835 cm –1 , which are assigned to the ν­(CO) band of methoxy species (CH 3 O*), the ν s (OCO) band of HCOO* species, and the ν s (CH 3 ) band of CH 3 O* species, respectively. , With the temperature elevated to 175 °C, absorption bands related to CH 3 O* species gradually decrease. Meanwhile, the band at 2930 cm –1 related to CH x species is observed .…”

“…32 As the temperature is elevated to 150 °C, three new peaks appear at 1062, 1395, and 2835 cm −1 , which are assigned to the ν(CO) band of methoxy species (CH 3 O*), the ν s (OCO) band of HCOO* species, and the ν s (CH 3 ) band of CH 3 O* species, respectively. 64,65 With the temperature elevated to 175 °C, absorption bands related to CH 3 O* species gradually decrease. Meanwhile, the band at 2930 cm −1 related to CH x species is observed.…”

Efficient Role of Nanosheet-Like Pr2O3 Induced Surface-Interface Synergistic Structures over Cu-Based Catalysts for Enhanced Methanol Production from CO2 Hydrogenation

“…To acquire detailed information about the reaction intermediates formed during the CO 2 hydrogenation at different reaction temperatures (150–250 °C) over Cu-based catalysts, in situ DRIFT experiments were conducted under a mixed feed gas (H 2 /CO 2 = 3:1). As presented in Figure , several bands (2966, 2872, 1590, and 1368 cm –1 ) are attributed to δ­(CH) + ν as (OCO), ν­(CH), ν as (OCO), and ν s (OCO) of surface bidentate formate species (HCOO*), respectively, while three bands at 2920, 2820, and 1056 cm –1 are assignable to ν as (CH 3 ), ν s (CH 3 ), and ν­(CO) of methoxy species (CH 3 O*), respectively. − The surface coexistence of formate and methoxy species reflects the occurrence of a formate–methoxy–methanol route in the CO 2 hydrogenation. , On Cu–ZnO/Pr 2 O 3 -NS, two bands of gas methanol (1030 and 1005 cm –1 ) can be detected at a low temperature of 150 °C, indicative of the easy occurrence of CO 2 hydrogenation to methanol. Furthermore, at 225 °C and above, two weak bands at 2175 and 2105 cm –1 correspond to gas CO, indicative of the occurrence of RWGS reaction. , Also, on Cu–ZnO/Pr 2 O 3 -NS, the bands of formate and methoxy species are much stronger than those of CO, further confirming the fact that large quantities of adsorption sites for CO intermediate are beneficial to the transformation of CO to produce methanol.…”

Bifunctional Metal‐free Heterogeneous Catalyst for the Synthesis of Methanol and Diols from CO2 and Epoxide

“…[21][22][23][24] In the recent time researchers are focusing their attention to synthesize methanol from CO 2 . [25][26] Considerably harsh reaction conditions (high temperature and high CO 2 + H 2 pressure) are necessary for achieving the direct hydrogenation of CO 2 to methanol [24] and this has motivated the scientists to focus their attention towards the reduction of CO 2 to methanol via. intermediate cyclic carbonates or carbamates.…”

“…In recent years many research groups focused on the synthesis of methanol from CO 2 either by its direct reduction or various indirect routes [16–19] because methanol can be utilized as an excellent alternative fuel, [20] solvent and feedstock for the production of many valuable chemicals [21–24] . In the recent time researchers are focusing their attention to synthesize methanol from CO 2 [25–26] . Considerably harsh reaction conditions (high temperature and high CO 2 +H 2 pressure) are necessary for achieving the direct hydrogenation of CO 2 to methanol [24] and this has motivated the scientists to focus their attention towards the reduction of CO 2 to methanol via .…”