Efficient Water Dissociation on Confined Ultrafine Pt via Pyridinic N-Enhanced Heavy d−π Interaction

Abstract

Sluggish water dissociation on Pt electrocatalysts results in poor performance for the alkaline hydrogen evolution reaction (HER) and thus greatly limits their practical application in industrial water electrolysis. Herein, ultrafine Pt nanoparticles have been confined into N-doped carbon by an in situ galvanic replacement reaction, and the pyridinic N-enhanced heavy d−π interaction is found to significantly enhance the water dissociation catalytic activity of Pt. The electron-deficient Pt generated by this enhanced heavy d−π effect exhibits an ultralow overpotential for hydrogen evolution of 10 mV at a current density of 10 mA cm −2 and an ultrahigh mass current density of 7.74 mA μg Pt −1 at an overpotential of 70 mV (7.9-fold higher than that of commercial Pt/C). Theoretical calculations reveal that the pyridinic N-enhanced heavy d−π effect can largely reduce the water dissociation energy barrier on Pt, thus greatly enhancing Pt's performance for the alkaline HER.

Interfacial Sulfur-Sensitization of PtNi Nanoalloy for Efficient Electrocatalytic Hydrogen Production in Alkaline Simulated Seawater

“…The Tafel slope for CdS/PtNi (Figure d) is 38 mV dec –1 , which is lower than that for PtNi alloy (42 mV dec –1 ), PtNi-sublimed S (117 mV dec –1 ), PtNi-organic S (144 mV dec –1 ), and Pt/C (45 mV dec –1 ). These findings suggest that the HER processes for CdS/PtNi take place through a Volmer–Heyrovsky pathway and the Heyrovsky step is rate-determining step. − In addition, the exchange current density ( j 0 ) determined by extrapolating the Tafel plot (Figure S16) of CdS/PtNi is estimated to be 2.73 mA cm –2 , which is much higher than that of other catalysts. Moreover, the real-time LSV curve without iR correction for CdS/PtNi also shows the best HER activity in alkaline simulated seawater (Figure S17).…”

Directed Mass and Electron Transfer Promoted by Hierarchical Porous Co–P–O Leads to Enhancement of the Overall Water Splitting Efficiency

“…The Tafel slope of Co–P–O2 is 97 mV dec –1 (Figure c), which is smaller than those of Co–P–O1 (132 mV dec –1 ), Co–P–O3 (124 mV dec –1 ), and benchmark RuO 2 (155 mV dec –1 ). The small Tafel slope of Co–P–O2 could aid practical applications, because it indicates that only a small overpotential increase is required to obtain a higher current density, − demonstrating the kinetic merit for the OER. In addition, analysis of cyclic voltammograms (CVs) outside the Faradaic regions, generated using different scan rates (Figures d and S9), shows that Co–P–O2 has a double-layer capacitance ( C dl ) value of 75.2 mF cm –2 , which is noticeably larger than those of Co–P–O1 (59.0 mF cm –2 ) and Co–P–O3 (59.2 mF cm –2 ), implying that Co–P–O2 has a higher electrochemically active surface area (ECSA) (Figure S10).…”

Recent advances in Ru-based electrocatalysts for oxygen evolution reaction

“…Due to the high surface energy, catalyst supports are important to avoid aggregation and/or overgrowth of the prepared nanoparticles/ clusters with desired sizes. 96,97 Recently, reducing the sizes of catalyst to singe atoms are becoming rising hotspots, which can make more efficient use of metal atoms. This design feature has aroused interest in exploring catalytically active components of single atoms and interfacial interactions that occur between active sites and supports.…”