Highly active CuZn/SBA-15 catalyst for methanol dehydrogenation to methyl formate: Influence of ZnO promoter

Activation and Conversion of Methanol over M@SixCyBz Catalysts: Revealing the Impact of Boron Concentration and Metal Types on Activity and Selectivity Regulation

To address the challenges of poor stability and low product selectivity associated with metal catalysts in the CH3OH to CHOOCH3 reaction, innovative M@SixCyBz catalysts were constructed for the first time. In this work, encapsulated M@SixCyBz catalysts (Sc@Si12C12, Sc@Si8C12B4, Sc@Si4C12B8, Si8C12B4, Cr@Si8C12B4, and Mn@Si8C12B4) are designed. First, molecular dynamics simulations demonstrate that M@SixCyBz catalysts exhibit high stability. Second, the mechanism of direct dehydrogenation of CH3OH to CHOOCH3 is systematically explored, the relevant data of each elementary reaction are calculated, and the reaction pathway is determined based on density functional theory (DFT). Finally, the electronic properties are calculated and analyzed. The results suggest that boron concentration can effectively regulate the product distribution and catalytic activity of CH3OH conversion, and the metal types can affect the activity of CHOOCH3 formation. Additionally, it is observed that the average charges of the carbon atoms at the reaction center of M@SixCyBz catalysts can be used as a descriptor for both activity and selectivity in CHOOCH3 formation. Among them, Cr@Si8C12B4 exhibits the highest activity for producing CHOOCH3. The models and calculation results can facilitate high-value utilization of CH3OH in the future.

Highly efficient hydrogenation of furfural to furfuryl alcohol over Cu-Al2O3-ZnO catalyst

The development of simple, efficient and economical catalysts for the hydrogenation of biomass to produce high value-added chemicals is of great significance in solving the energy crisis. In this work, a series of non-precious metal catalysts (Cu-Al2O3-ZnO) with different defect sites were prepared by etching Devarda's alloy. Under optimized mild reaction conditions, the furfural conversion and furfuryl alcohol selectivity are both greater than 99.0%, and the catalyst has good reusability. Characterisation and experiments were used to investigate the activate species for hydrogenation reaction. It can be proved that the low-valent Cu species in the Cu-Al2O3-ZnO catalysts play an important role as adsorption and dissociation sites for H2. Different etching degrees and sample reduction temperatures of the alloy can be used to adjust the content of acidic sites such as Al2O3 and CuO, which have appropriate adsorption properties for furfural. ZnO promotes the dispersion of the Cu species and enhances the accessibility of the active sites. The etching method achieves the interaction between species to further enhance the stability and activity of the catalyst. The catalytic performance of the catalyst is very competitive and this study provides a new method for the efficient hydrogenation of furfural to furfuryl alcohol.

Recent Advances in Carbon Dioxide Adsorption, Activation and Hydrogenation to Methanol using Transition Metal Carbides

The inevitable emission of carbon dioxide (CO₂ ) due to the burning of a substantial amount of fossil fuels has led to serious energy and environmental challenges. Metal-based catalytic CO₂ transformations into commodity chemicals are a favorable approach in the CO₂ mitigation strategy. Among these transformations, selective hydrogenation of CO₂ to methanol is the most promising process that not only fulfils the energy demands but also re-balances the carbon cycle. The investigation of CO₂ adsorption on the surface of heterogeneous catalyst is highly important because the formation of various intermediates which determines the selectivity of product. Transition metal carbides (TMCs) have received considerable attention in recent years because of their noble metal-like reactivity, ceramic-like properties, high chemical and thermal stability. These features make them excellent catalytic materials for a variety of transformations such as CO₂ adsorption and its conversion into value-added chemicals. Herein, the catalytic properties of TMCs are summarize along with synthetic methods, CO₂ binding modes, mechanistic studies, effects of dopant on CO₂ adsorption, and carbon/metal ratio in the CO₂ hydrogenation reaction to methanol using computational as well as experimental studies. Additionally, this Review provides an outline of the challenges and opportunities for the development of potential TMCs in CO₂ hydrogenation reactions.

A Prospective Life Cycle Assessment of Electrochemical CO2 Reduction to Selective Formic Acid and Ethylene

Converting CO₂ into valuable C₁ -C₂ chemicals through electrochemical CO₂ reduction (ECR) has potential to remedy the ever-increasing climate problems owing to the intensification of industrial activity. In this work, cradle-to-gate life cycle assessment (LCA) was performed to quantify the environmental impacts of formic acid (FA) and ethylene production through ECR benchmarked with the conventional processes. At the midpoint level, global warming potential (GWP) effects of FA and ethylene production through ECR recorded 5.6 and 1.6-times that of the conventional process, respectively. Although ECR currently has limited environmental benefits, the incorporation of hydropower has vast potential after evaluating four sustainable electricity sources, namely hydropower, wind, solar, and biomass. Notably, ECR to FA recorded a 24 % reduction in petrochemical usage. For ethylene production, human health damage, ecosystem damage, and petrochemical use were reduced by 67, 94, and 110 %, respectively. Sensitivity analysis indicated that a sustainable energy supply chain for ECR will accelerate the development of a circular economy.

Insights into the crucial role of Zn promoter for methanol dehydrogenation to methyl formate over Cu(111) catalyst

Zn-doped Cu(111) alloy (Cu3Zn(111)) and Cu(111) surfaces were built using density functional theory (DFT) calculation to investigate the roles of Zn promoter in methyl formate (MF) synthesis by direct dehydrogenation...