Screening of C₃N-Supported Monometallic Atom Catalysts for Selective C═O Hydrogenation of Crotonaldehyde

The hydrogenation of crotonaldehyde (CRAL) to crotyl alcohol (CROL) represents a crucial industrial process with broad applications in chemical synthesis. However, developing high-performance catalysts that simultaneously achieve both high CROL yield and selectivity remains a significant challenge. In this study, we employed density functional theory (DFT) calculations to investigate monometallic atom catalysts based on a transition metal (TM) anchoring model within dual carbon vacancies (VCC) in two-dimensional monolayer C3N materials for selective CRAL hydrogenation. Our results demonstrate that the synergistic interaction between TM atoms and coordinating carbon atoms facilitates H2 dissociation and H atom diffusion. Furthermore, the C═O group’s binding strength with the metal center can be precisely modulated by selecting appropriate metal species at the active site, enabling selective hydrogenation toward CROL. Through systematic screening of 25 TM-C3N configurations, we identified midtransition metal Mn as the optimal catalyst. The Mn–C3N system exhibits an exceptionally low C═O hydrogenation energy barrier (0.82 eV) and a high turnover frequency (TOF) of 0.020 mol s–1. The high-spin characteristics of Mn coupled with its lower d-band center position were found to be critical factors governing the remarkable selectivity. These theoretical insights provide a foundation for designing efficient catalysts for selective CRAL hydrogenation.