Self-Optimized Ligand Effect in L1₂-PtPdFe Intermetallic for Efficient and Stable Alkaline Hydrogen Oxidation Reaction

Abstract

It is of paramount importance to explore high efficient and stable electrocatalysts toward anodic hydrogen oxidation reaction (HOR) in anion exchange membrane fuel cells. Herein, a new class of ternary (Pt 0.9 Pd 0.1 ) 3 Fe intermetallic is developed with excellent performance toward alkaline HOR. Specifically, the Pd-substitution facilitates the formation of L1 2 -Pt 3 Fe intermetallic at a lower annealing temperature. Electrochemical analysis and density functional theory calculations indicate that the in-situ formed interstitial alloying PdH x during the electrochemical cycle widens the d-band structure of (Pt 0.9 Pd 0.1 ) 3 Fe and shifts downward the d-band center toward the Fermi level. The optimized ligand effect from PdH x gives rise to the encouraging activity for alkaline HOR. Meanwhile, a stepby-step monitoring technique and ex situ CO-stripping voltammetry jointly demonstrate that ordered atoms' arrangement of (Pt 0.9 Pd 0.1 ) 3 Fe intermetallic contributes to stabilize the local coordination environment and enables the maintenance of the ligand effect from the in situ formed Fe/Fe(OH) x heterostructure. Negligible decay in electrochemical surface areas of (Pt 0.9 Pd 0.1 ) 3 Fe intermetallic after a given accelerated durability test confirms the significant advantage in stability over Pt 3 Fe alloy. This work sheds light on the significance of ligand effects optimization and real-time tracing of the catalytic process to the structure−activity relationship establishment and subsequent catalyst designs.

Engineering Ir Atomic Configuration for Switching the Pathway of Formic Acid Electrooxidation Reaction

“…[18] The promoted formation of intermetallics is also found on the Pt and Pdbased nanocatalysts when partial metal atoms were replaced by another metal. [19] In addition, the (111) peaks of O H -Ir 3 V/C and O-(Ir 0.9 Pd 0.1 ) 3 V/C is sharper than that of Ir/C, which could be ascribed to the increased average nanoparticle size (Figure S1, Supporting Information).…”

RuO 2 as promoter in Pt‐RuO 2 ‐ nanostructures/carbon composite, a pH ‐universal catalyst for hydrogen evolution/oxidation reactions

“…The i 0,m and i 0,s values for RuO 2 ‐Pt/C in 0.1 M KOH are 1833 mA/mg Pt,Ru and 1.8 mA/cm 2 Pt,Ru respectively. The HOR activity of RuO 2 ‐Pt/C was far better over Pt‐based reported catalysts in base media 51‐59 . For example, J. Zheng et al 50 reported i 0 value for Pt disk electrode was 0.21 mA.cm −2 in 0.1 M KOH.…”

Noble Metal‐Based Multimetallic Nanoparticles for Electrocatalytic Applications

“…On the other hand, the substitution of 10% of Pt in Pt 3 Fe with Pd was recently found to promote atomic ordering in the L1 2 phase through a simple impregnation method. [ 140 ] The role of Pd was not limited to that, but also included the formation of PdH x to tune the electron density of the intermetallic nanoparticles.…”