In situ nitrogen-doped carbon-coated nickel nanoparticles derived from Hofmann metal–organic frameworks for efficient bond-hydrogenation and cleavage of C–O linkages

Abstract

Aromatic compounds and cycloalkanes are crucial for producing fine chemicals and pharmaceuticals, typically derived from coal and lignin through hydrogenation. Nickel (Ni) is a cost-effective and recyclable catalyst for these reactions, but its nanoparticles often agglomerate at high temperatures, reducing active sites and performance. In this study, we developed nitrogen-doped carbon-coated Ni nanoparticles derived from Hofmann metal–organic frameworks (MOFs). The bimetallic sites in Hofmann MOFs increased the Ni content in the catalyst to 67.9%, with highly exposed active crystal facets, creating more active sites. The nitrogen-doped carbon, produced from pyrolyzing Hofmann MOFs with high pyrrole nitrogen content, effectively prevented Ni particle agglomeration and improved surface conductivity. Experimental and computational studies showed that pyrrole nitrogen increases electron density and forms a chemical bond with Ni by attracting its lone pair electrons, enhancing binding energy and adsorption capacity. The optimized catalyst fully converted benzyl phenyl ether (BPE) into monocyclic compounds under mild conditions and demonstrated high activity for other C–O bond-containing compounds. This work provides a stable and efficient catalyst for transforming low-cost resources into valuable chemicals.