Insights into Solvent Effects on Ni-BTC-Derived Ni@C Catalysts for the Hydrogenation of Phenolic Compounds

The structural characteristics of metal-organic framework (MOF)-derived materials are strongly influenced by synthesis solvents. Herein, Ni-BTC MOFs were solvothermally synthesized in different solvents, and their derived Ni@C catalysts were achieved through a one-step pyrolysis. The synthesis solvents significantly affect the microstructures and catalytic performance of the Ni@C catalysts during the hydrogenation of phenolic compounds. Remarkably, employing a ternary solvent system composed of deionised water (DI), N,N-dimethylformamide (DMF), and ethylene glycol (EG) in a specific volume ratio leads to the production of a Ni@C-5DI:10DMF:3EG catalyst with unique hollow sphere structures. The catalyst exhibits a larger specific surface area, smaller and uniformly dispersed Ni nanoparticles, higher Ni⁰/Ni²⁺ ratio, higher degree of graphitization, and lower density of acidic sites. Consequently, Ni@C-5DI:10DMF:3EG achieves a superior reaction rate of 28.6 mmol·h^-1·g^-1, surpassing most nonprecious metal catalysts. Furthermore, Ni@C-5DI:10DMF:3EG exhibits a favorable reusability. These findings offer valuable insights into the design of MOF-derived catalysts and their applications in catalytic hydrogenation.