Size-dependent electronic interface effect of Pd nanocube-based heterojunctions on universally boosting phenol hydrogenation reactions

As mainstream catalysts for phenol hydrogenation with good reusability and high selectivity under mild conditions, Pt- and Pd-based heterogeneous catalysts suffer from unsatisfied catalyst costs. The structures of metals (i.e., particle sizes, alloy structures, and porosity) and the acidity of the support were optimized to boost the intrinsic activity of noble metal nanocatalysts with a maximum promoting factor of 3.3. There is considerable scope for exploring more powerful methods for boosting the mass activity of metal catalysts. Herein, we demonstrate a novel size-dependent electronic interface effect in the heterojunctions of Pd nanocubes and sulfur-doped carbon (SC) supports to enhance phenol hydrogenation activity. Theoretical calculations and experimental results indicate that the size-dependent electron deficiency of Pd nanocubes on the designed SCs as electron acceptors results in an unexpected and universal promotion of phenol hydrogenation activity, outperforming free-standing Pd nanocubes by a factor of 9–19.