Highly efficient hydrogenolysis of lignin-derived diphenyl ether over Ni nanoparticles on carbon nanosphere under mild condition

Abstract

Efficient catalytic cleavage of C–O bonds in lignin derivatives is crucial for converting these compounds into valuable chemicals. The reliance on expensive noble metals and harsh operational conditions poses significant challenges for existing catalyst systems. In response, we have developed a Ni-based catalyst through an acetone-driven etching-deposition-pyrolysis technique, tailored to maximize exposure of Ni active sites. Systematic optimization of the support's surface properties, pyrolysis temperature, and Ni loading were instrumental in augmenting C–O bond cleavage efficiency in aromatic ethers. Remarkably, the catalyst, 2Ni/CNS-500, facilitated the cleavage of the C–O bond in diphenyl ether (DPE) to monomers under mild conditions (140 °C for 2 h under 1 MPa H2 pressure), surpassing the performance of several existing heterogeneous Ni-based catalysts. The catalyst's superior performance is attributed to the robust interaction between nickel and carbon nanosphere (CNS) species and the significant exposure of nickel active sites. Versatility was demonstrated with a variety of lignin-derived substrates, including 4-phenoxy phenol (4-O-5), benzyl phenyl ether (α-O-4), phenyl ethyl benzene (β-O-4), and anisole, showcasing the catalyst's broad applicability. Therefore, the acetone-driven etching-deposition-pyrolysis strategy is considered a promising method for preparing highly dispersed nickel-based hydrogenolysis of lignin derivatives catalysts with broad industrial application prospects.