Phosphorene-Supported Rh Carbonyl Hydride Fragments as Efficient Heterogeneous Single-Site Catalysts for Ethylene Hydroformylation: A First-Principles Investigation

Abstract Hydroformylation is a 100% atom-economy industrial process that converts olefins and syngas to aldehydes, typically catalyzed by homogeneous Rh phosphine or phosphite complexes, though catalyst recovery and ligand stability remain persistent challenges. Here, we theoretically investigate HRh(CO)2 fragments supported on black phosphorene (BP) that forms in situ via the reaction of Rh(CO)2(acac) (acac = acetylacetonate) with BP under hydroformylation conditions, as a heterogeneous single-site alternative. Using first-principles thermodynamics coupled with microkinetic simulations to treat the effect of temperature and content of the reaction feed, we demonstrate that the reversible and competitive coordination of CO and surface phosphorus atoms to the Rh center enables ethylene hydroformylation to proceed through both the classical Heck–Breslow pathway and a surface-P involving its variant, and the turnover frequency (TOF) for propanal is up to ∼15,000 h–1 at 450 K. Notably, the latter pathway, previously considered kinetically insignificant, contributes substantially to the TOF. In full agreement with the thermodynamic stability of the participating intermediates, the TOF increases with temperature and H2 content but decreases with CO content in the reaction feed. Furthermore, the near-quantitative propanal selectivity arises from the thermodynamically unfavorable formation of byproduct intermediates, which effectively suppresses the competing pathways. We expect these findings help to establish the principles for the rational development of heterogeneous single-site hydroformylation catalysts.