NH3 annealing for preparing Pt nanocluster@N-doped hollow mesoporous carbon spheres with enhanced hydroxyl aldehyde hydrogenation

Abstract

The development of nitrogen-doped mesoporous carbon spheres (N-CS) integrated with metal nanoclusters for enhanced hydroxyl aldehyde hydrogenation remains challenging. In this work, a NH₃ annealing strategy was employed to prepare Pt nanocluster-loaded nitrogen-doped mesoporous carbon spheres (Pt@N-CS) catalysts. In Pt@N-CS, Pt nanoclusters are anchored onto nitrogen-doped carbon spheres via strong Pt–N interactions, which facilitate electron transfer and effectively suppress Pt leaching and agglomeration. The hydrogenation of 2-ethyl-3-hydroxyhexanal using Pt@N-CS shows nearly 98 % conversion and yield, with selectivity close to 100 % under optimal conditions. Density functional theory calculations reveal that nitrogen doping induces electron-deficient Pt sites, which enhance the adsorption and activation of H₂ (−0.93 eV) and EHA (−1.66 eV). The charge redistribution at the metal-support interface could strengthen the interaction between Pt and the carbonyl group of 2-ethyl-3-hydroxyhexanal. Consequently, the energy barrier of the rate-determining step is reduced by 0.06 eV, thereby facilitating the hydrogenation process under mild conditions.