Recently, Wang Guozhong, a researcher from the Institute of Solid State Physics of the Chinese Academy of Sciences, Hefei Institute of Materials Science, made progress in the research on the performance of nitrogen doped carbon layer control catalysts. This study synthesized nickel catalysts encapsulated in nitrogen doped carbon layers and silica composite carriers, and investigated the effects of carbon layer, carbon layer thickness, and nitrogen doping on the water phase hydrogenation performance of vanillin.

Water is an environmentally friendly and readily available solvent in the field of green chemistry, and plays an important role in chemical reactions. However, traditional catalysts face problems such as active metal loss, leaching, and deactivation in aqueous reactions, which in turn affect catalytic efficiency and stability. This study indicates that the encapsulation strategy can reduce the loss of active metals. The nitrogen doped carbon layer derived from resorcinol formaldehyde can enhance the affinity between the catalyst surface, gas molecules, and organic reactants through its inherent hydrophobic properties without affecting reaction mass transfer, thereby improving the hydrogenation activity and stability of the catalyst. It is a promising coating material in the field of liquid-phase catalysis.

This study encapsulated metallic nickel in a nitrogen doped carbon and silica composite amphiphilic carrier（ SiO2@Ni @NC) and apply this catalyst to the aqueous hydrogenation reaction of vanillin. Research has found that, SiO2@Ni @The NC catalyst exhibits excellent activity and stability in aqueous reactions, achieving nearly 100% conversion of vanillin to 4-hydroxymethyl-2-methoxyphenol at room temperature, with no significant decrease in activity after 5 cycles.

This efficient catalytic performance is attributed to the synergistic effect between the active metal, nitrogen doped carbon layer, and SiO2. Among them, the hydrophilic SiO2 core allows the catalyst to be uniformly dispersed in the aqueous phase, thereby better contacting the reactants. The nitrogen doped carbon layer, on the other hand, plays a multiple role in protecting the internal metal from oxidation or leaching, serving as a reducing agent to reduce the internal metal, and performing electronic modification on the active metal. In addition, the carbon layer can regulate the microenvironment around the active site by enriching H2 and organic reactants.

Furthermore, this study confirmed the role of nitrogen doped carbon layers in promoting reactant adsorption and spontaneous hydrogen dissociation through density functional theory calculations, and elucidated the catalytic mechanism of vanillin aqueous hydrogenation. The carbon coating strategy proposed in this work provides a new approach for constructing efficient and stable room temperature aqueous hydrogenation catalysts.

The relevant research results are published in Advanced Science. The research work is supported by the National Natural Science Foundation of China.

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