Spillover Hydrogen Boosts Nitroarene Hydrogenation to Industrial Activity with Ppm-Level Platinum Single Atoms.

The application of noble single-atom catalysts (SACs) at trace loadings is constrained by a low space-time yield, presenting a formidable challenge in elevating the activity of SACs to be comparable to industrial catalysts in nitroarene hydrogenation. In this study, the spillover hydrogen from a carbon-coated nickel support (Ni@C) coupled with 300 ppm platinum results in a 25.7-fold enhancement in turnover frequency (TOF, 44.1 s^-1), thereby achieving a space-time yield equivalent to 1 wt.% Pd/C industrial hydrogenation catalyst. Remarkably, the Pt₁/Ni@C catalyst preserves excellent stability under rigorous conditions, including acidic, basic, and oxidative environments. Density functional theory (DFT) calculations reveal that spillover hydrogen effectively reduces the hydrogenation energy barrier, with the energy barrier height inversely correlated to the density of adsorbed spillover hydrogen on Pt single atom. Extrapolating the enhanced hydrogenation effect to other SACs and nitroarene substrates shows that spillover hydrogen can either promote or inhibit hydrogenation processes. The density of adsorbed spillover hydrogen serves as a predictive descriptor for discerning the direction of the synergistic effect in single-atom catalyzed hydrogenation. This study provides insightful guidance for the rational design of more efficient and industrially viable SACs exploiting hydrogen spillover.