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

Abstract By providing dual active sites to synergistically accelerate H 2 O 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 Pt 3 Fe alloys (Pt 3 Fe/NMCS‐A), as a highly‐efficient electrocatalyst for pH‐universal HER, are reported. The Pt 3 Fe/NMCS‐A exhibits low overpotentials ( η 10 ) of 13, 29, and 48 mV to deliver 10 mA cm −2 in 0.5 m H 2 SO 4 , 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 ( ε 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 Pt 3 Fe/NMCS‐A to dissociate H 2 O 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 Pt 3 Co and Pt 3 Ni alloys with excellent HER activity in pH‐universal electrolytes, demonstrating the great potential of these Pt‐based alloys for practical applications.