Selective Electrochemical Hydrogenation of Phenol with Earth‐abundant Ni−MoO₂ Heterostructured Catalysts: Effect of Oxygen Vacancy on Product Selectivity

Abstract

Herein, we report highly efficient carbon supported NiÀ MoO 2 heterostructured catalysts for the electrochemical hydrogenation (ECH) of phenol in 0.10 M aqueous sulfuric acid (pH 0.7) at 60 °C. Highest yields for cyclohexanol and cyclohexanone of 95 % and 86 % with faradaic efficiencies of ~50 % are obtained with catalysts bearing high and low densities of oxygen vacancy (O v ) sites, respectively. In situ diffuse reflectance infrared spectroscopy and density functional theory calculations reveal that the enhanced phenol adsorption strength is responsible for the superior catalytic efficiency. Furthermore, 1-cyclohexene-1-ol is an important intermediate. Its hydrogenation route and hence the final product are affected by the O v density. This work opens a promising avenue to the rational design of advanced electrocatalysts for the upgrading of phenolic compounds.

Carbon-Coated NiMoOx Bimetallic Catalyst for Selective Hydrodeoxygenation of Lipids to Fatty Alcohols

“…The roles of Mo and carbon coating have been illustrated: (1) Adding the appropriate Mo can inhibit the oxidation of Ni species to promote H 2 activation and increase the Lewis basic sites to enhance the absorption of lipids. (2) The carbon layer first promotes the adsorption of lipids and the generation of corresponding alcohols through a HDO process, while alcohols quickly desorb due to the carbon layer and thus do not undergo further HDO to generate corresponding alkanes. Different lipids including stearic acid, palmitic acid, methyl stearate, and glyceryl tristearate can be applied in this protocol.…”

“…To achieve carbon peak and neutrality targets, much attention has been paid to the development of biomass instead of traditional petroleum oil for energy and chemical applications. − Lipids (animal fats, vegetable oils, fatty acids, and their esters) are well-known to form basic units of membrane structure and energy storage in animals and plants. − The global oilseed production in 2021 was approximately 600 million tons, and oilseed not only is one of the cheapest and most easily available biomasses but also has a molecular structure similar to that of fossil fuels, making it easier to convert to fuel or other high-value chemical raw materials compared to lignocellulose. − Therefore, the conversion of lipids to high value-added chemicals through chemical reactions has become a research focus in lipid chemistry. − …”

Enrichment of Polarized Alkynes over Negatively Charged Pt for Efficient Electrocatalytic Semihydrogenation

“…The production of alkenes from the hydrogenation of alkynes is a pivotal and fundamental transformation process in the chemical industry due to its wide applicability in the synthesis of polymers, fine chemicals, and pharmaceuticals. − The conventional hydrogenation of alkynes is widely involved with molecular hydrogen and/or expensive and hazardous organic hydrogen sources, leading to considerable safety, environmental, and economic costs. − Alternative strategies are thus extended to the electrocatalytic hydrogenation of unsaturated organic small molecules for sustainable alkene production via employing hydrogen protons from green and economic water molecules. − The main challenge of selective hydrogenation of alkynes to alkenes lies in effectively suppressing both the undesired overhydrogenation of alkenes to alkanes and the double-bond isomerization process while enhancing the reaction rate of semihydrogenation. , Nevertheless, the endeavor to improve the selectivity has typically relied upon restricting overhydrogenation through the incorporation of ligands and other low-activity species into active components, albeit at the cost of sacrificing the intrinsic activity of catalytic centers. ,− The development of sustainable methodologies, founded upon the rational design of the high activity and selectivity catalysts, especially powerful electrocatalysts, has emerged as an urgent requirement in practical semihydrogenation systems for alkene production.…”