Ni‐Based Metal Cavities‐Mediated Ensemble Effect for Catalytic Hydroconversion of Lignin into Aromatic Monomers

An efficient catalytic hydroconversion of lignin into aromatic monomers (AMs) is not only critical for the economic viability of lignin refining, but also reduces dependence on fossil fuels. Nevertheless, current molecular‐level studies on H 2 activation in catalytic hydroconversion of lignin are primarily focused on single‐atom catalysts (SACs) or nanoparticle catalysts (NPCs), leaving the H 2 activation capabilities of metal cavities largely unexplored. Herein, we report the construction of a composite material featuring a multi‐Ni‐atom metal cavities for the catalytic hydroconversion of lignin. This study employs a dual‐induction mechanism to synthesize multi‐Ni‐atom metal cavity catalysts exhibiting an ensemble effect: Initially, hydrogen bonding mediates the increase in intermolecular size of the Ni species precursor; subsequently, high‐temperature thermal induction generates multi‐Ni‐atom metal cavities with the ensemble effect. In contrast to SACs or NPCs, these metal cavity structures promote efficient electron transfer between the graphitic carbon black support and the Ni δ+ species via an ensemble effect, thereby enhancing the intrinsic ability of Ni species to activate H 2 into H*. Moreover, the π–π interaction between the electron‐deficient graphitized carbon black support and electron‐rich aromatic rings (ARs) in lignin promotes the fixation of ARs, suppressing their over‐hydrogenation. This leads to a lignin conversion rate of 81.0% and an AM yield of 45.5 wt.%, demonstrating excellent ensemble catalytic performance. The Ni‐based metal cavity catalysts with the ensemble effect constructed in this study provide theoretical support for obtaining lignin‐derived small‐molecule platform compounds.