Enhancing Catalytic Performance through Subsurface Chemistry: The Case of C₂H₂ Semihydrogenation over Pd Catalysts

Abstract

Subsurface chemistry in heterogeneous catalysis plays an important role in tuning catalytic performance. Aiming to unravel the role of subsurface heteroatoms, C 2 H 2 semihydrogenation on a series of Pd catalysts doped with subsurface heteroatom H, B, C, N, P, or S was fully investigated by density functional theory (DFT) calculations together with microkinetic modeling. The obtained results showed that catalytic performance toward C 2 H 2 semihydrogenation was affected significantly by the type and coverage of subsurface heteroatoms. The Pd-B 0.5 and Pd-C 0.5 catalysts with 1/2 monolayer (ML) heteroatom coverage, as well as Pd-N, Pd-P, and Pd-S catalysts with 1/16 ML heteroatom coverage, were screened to not only obviously improve C 2 H 4 selectivity and activity but also effectively suppress green oil. The essential reason for subsurface heteroatoms in tuning catalytic performance is attributed to the distinctive surface Pd electronic and geometric structures caused by subsurface heteroatoms. In the Pd-B 0.5 and Pd-C 0.5 catalysts, the Pd surface electronic and geometric effects play the dominant role, while the geometric effect plays a key role in the Pd-N, Pd-P, and Pd-S catalysts. The findings provide theoretically valuable information for designing high-performance metal catalysts in alkyne semihydrogenation through subsurface chemistry.

Dynamics of Pd Subsurface Hydride Formation and Their Impact on the Selectivity Control for Selective Butadiene Hydrogenation Reaction

“…In another study, involving the hydrogenation of 1,3-butadiene on Pd (110)-oriented surfaces, it was observed that the presence of both weakly π-bonded 1,3-butadiene and subsurface hydrogen atoms is required to achieve catalytic activity [ 12 ]. Furthermore, Wu et al [ 13 ] also attributes enhancements in catalytic performance to subsurface chemistry. In this cited work, focused on the partial hydrogenation of acetylene over Pd catalysts, the authors claim that the main reason for the catalytic performance of the active site can be tuned based on the distinctive electronic and geometric structures of Pd derived as a result of the presence of the corresponding subsurface heteroatoms.…”