Highly Selective Synthesis of Ethanol via CO₂ Hydrogenation over CoMoC_x Catalysts

Abstract

Hydrogenation of CO 2 to ethanol is one of the promising and emerging routes for the transformation of CO 2 into value-added chemicals. In the present work, series of CoMoCx catalysts were prepared by using ionic liquids as all-in-one precursors and adjusted the proportional and electronic properties of CoMoC x catalysts by modifying carburization temperature, the efficiency of CO 2 to ethanol hydrogenation was optimized. Under the optimal reaction conditions (180°C and 2 MPa), the selectivity of ethanol reached 97.4 %, and the yield of ethanol arrived at 0.528 mmolg cat. À 1 h À 1 . In situ DRIFTS results revealed that a nucleophilic attack on the carbon of CH 3 O* by a formyl to form ethanol.

Hydrogenation of Carboxylic Acids, Esters, and Related Compounds over Heterogeneous Catalysts: A Step toward Sustainable and Carbon-Neutral Processes

“…This step is also in accordance with several other studies. 512 The existence of alkali metal ions (M + ) could enhance the activity and stabilize the formyl intermediate by providing an electron-rich environment for the Cu center. Through the reductive elimination, Cu + −Cu + sites were regenerated, together with the continuous production of ethanol, methanol, or water.…”

“…Later in 2019, the Wang and Xiao group 517 further modified the catalyst with Ni, which accelerated the formation of CH x * and as a result enhanced the ethanol production (Table 18, entry 6). Regarding the use of Co, a CoMoC x catalyst was developed by Xiao, Wu and co-workers 512 in 2021 and showed 97.4% selectivity toward ethanol with its formation rate of 0.528 mmol g cat −1 h −1 at 180 °C. A recent breakthrough was made by Wang and co-workers 511 using a Cu supported on Zr 12 -MOF.…”

New Insights on Catalytic Valorization of Carbon Dioxide by Conventional and Intensified Processes

“…Ethanol is another compound of interest that can be obtained through thermochemical CO 2 valorization (Reaction ). − ,− In comparison with methanol and hydrocarbons, ethanol production is considered to occur almost exclusively through the intermediate RWGS reaction (Reaction ). ,, Combining reaction with the RWGS leads to the Reaction : , 2 normalC normalO + 4 normalH 2 ⇔ normalC 2 normalH 5 normalO normalH + normalH 2 normalO goodbreak0em1em⁣ normalΔ H = prefix− 256 .25em normalk normalJ / normalm normalo normall 2 normalC normalO 2 + 6 normalH 2 ⇔ normalC 2 normalH 5 normalO normalH + 3 normalH 2 normalO goodbreak0em1em⁣ normalΔ H = prefix− 73.6 .25em normalk normalJ / normalm normalo normall …”

“…Although the RWGS reaction is endothermic, this positive enthalpy is outweighed by the negative enthalpy of the reaction converting CO into ethanol, thus making the global ethanol production process exothermic, favored by relatively low temperatures . It has been demonstrated by Kusama et al that ethanol yield could be maximized at temperatures between 240 and 260 °C …”

Hydrogenation of carbon dioxide (CO2) to fuels in microreactors: a review of set-ups and value-added chemicals production

“…Recent studies have shown that nonnoble and metal-based catalysts are investigated to provide highly efficient liquid phase ethanol from CO 2 hydrogenation. 39,69,71,[100][101][102][103][104][105][106] Direct CO 2 hydrogenation to ethanol is represented below: 107…”