Shedding light on the effect of pore orientation on hydrogenation over carbon-supported single-atom catalysts

Rational control of pore orientation holds great potential to enhance mass transfer in carbon-supported single-atom catalysts (SACs), thereby increasing single-atom site utilization and catalytic performance; however, this strategy remains underexplored in catalytic hydrogenation reactions. In this paper, cobalt single-atom catalysts supported on oriented porous carbon (Co-SAC/OPC) and non-oriented porous carbon (Co-SAC/NOPC) were synthesized using the hard-template method, and their performance in hydrogenation reactions was systematically investigated using para-chloronitrobenzene (p-CNB) hydrogenation as a model reaction. Results from experiments (diffusion, substrate size–dependent conversion, and recycling) and finite‑element analysis show that oriented pores facilitate p‑CNB diffusion more effectively than non‑oriented pores. This faster transfer enhances the accessibility and utilization of single-atom cobalt sites, resulting in significantly improved hydrogenation performance of Co-SAC/OPC. This work establishes a general strategy for enhancing the performance of carbon‑supported single‑atom catalysts in hydrogenation catalysis and related reactions.