Modulating the d-Band Center Enables Ultrafine Pt3Fe Alloy Nanoparticles for pH-Universal Hydrogen Evolution Reaction

By providing dual active sites to synergistically accelerate H2O dissociation and H+ reduction, ordered intermetallic alloys usually show extraordinary performance for pH-universal hydrogen evolution reaction (HER). Herein, activated N-doped mesoporous carbon spheres supported intermetallic Pt3Fe alloys (Pt3Fe/NMCS-A), as a highly-efficient electrocatalyst for pH-universal HER, are reported. The Pt3Fe/NMCS-A exhibits low overpotentials (eta(10)) of 13, 29, and 48 mV to deliver 10 mA cm(-2) in 0.5 m H2SO4, 1.0 m KOH, and 1.0 m phosphate buffered solution (PBS), respectively, as well as robust stability to maintain the overall catalytic performances. Theoretical studies reveal that the strong Pt 5d-Fe 3d orbital electronic interactions negatively shift the d-band center (epsilon(d)) of Pt 5d orbital, resulting in reduced H* adsorption energy of Pt sites and enhanced acidic HER activity. With Pt and Fe acting as co-adsorption sites for H* and *OH intermediates, respectively, a low energy barrier is required for Pt3Fe/NMCS-A to dissociate H2O to afford H* intermediates, which greatly promotes the H* adsorption and H-2 formation in alkaline and neutral conditions. The synthetic strategy is further extended to the synthesis of Pt3Co and Pt3Ni alloys with excellent HER activity in pH-universal electrolytes, demonstrating the great potential of these Pt-based alloys for practical applications.

Automated summary

By providing dual active sites for H2O dissociation and H+ reduction, ordered intermetallic alloys exhibit extraordinary performance for pH-universal hydrogen evolution reaction (HER). In this study, activated N-doped mesoporous carbon spheres supported intermetallic Pt3Fe alloys (Pt3Fe/NMCS-A) are reported as highly-efficient electrocatalysts for pH-universal HER. The synthetic strategy is further extended to the synthesis of Pt3Co and Pt3Ni alloys with excellent HER activity in pH-universal electrolytes, showing great potential for practical applications.