Confined Ultrafine Pt in Porous Carbon Fibers and Their N-EnhancedHeavy d-?Effect

The heavy d-pi effect is an important theoretical model for strong Pt-Cinteraction, and its enhancement is critical to the high-performance design of Pt/Celectrocatalysts. Common chemical N-doping to the carbon support can providepossibilities for enhanced electrocatalysis but most often leads to random interaction withPt nanoparticles (Pt-NPs) and uncontrollable tuning of the heavy d-pi effect. Directionalconfinement of Pt-NPs within N-doped carbon to directly enhance the heavy d-pi effect istherefore mostly preferred but rarely reported. Herein, confined ultrafine Pt-NPs in N-doped porous carbonfibers (Pt@NDPCF) were obtained by a combination methodinvolving electrospinning, carbonization, and directional replacement. Such a syntheticstrategy leads to highly dispersed, ultrafine Pt-NPs in hierarchically porous carbonfibersand a strong directional interaction of Pt with pyridinic N, which significantly enhancesthe heavy d-pi effect, greatly facilitating electron transfer and optimizing Pt 5d orbitals.Based on these advances, Pt@NDPCF exhibited outstanding activity and superiordurability in the hydrogen evolution reaction (HER), with 24 mV lower overpotential at10 mA cm-2and a much smaller activity loss after 10,000 cycles of durability tests in comparison with a commercial Pt/C catalyst.This work sheds new lights on the design of high-performance Pt-based nanomaterials toward HER or other practical applications

Automated summary

The heavy d-pi effect is an important theoretical model for strong Pt-C interaction, and confining Pt nanoparticles within N-doped carbon can enhance this effect. In this study, confined ultrafine Pt-NPs in N-doped porous carbon fibers were successfully synthesized and showed outstanding catalytic activity and durability in the hydrogen evolution reaction.