Constructing Gradient Orbital Coupling to Induce Reactive Metal-Support Interaction in Pt-Carbide Electrocatalysts...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Reactive metal-support interaction (RMSI) is a key strategy for tuning supported metal catalyst performance.
• Conventional RMSI induction via thermal reduction often leads to metal encapsulation, hindering mechanistic studies and applications.
• A reductant-free approach is needed to overcome limitations in RMSI research and application.

Purpose of the Study:

• To develop a novel strategy for inducing RMSI in platinum-carbide systems without using a reductant.
• To synthesize and characterize L1₂-Pt₃M-MCₓ intermetallic electrocatalysts.
• To investigate the mechanism of RMSI induction and its effect on catalytic activity, particularly for methanol oxidation.

Main Methods:

• A gradient orbital coupling construction strategy was employed to induce RMSI.
• Density Functional Theory (DFT) calculations were used to elucidate the electronic structure and reaction mechanisms.
• Electrochemical performance was evaluated using half-cell tests and a direct methanol fuel cell.

Main Results:

• The strategy successfully induced RMSI in Pt-carbide systems, forming L1₂-Pt₃M-MCₓ intermetallic electrocatalysts (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W).
• DFT calculations revealed that gradient d(M)-2p(C)-5d(Pt) orbital coupling facilitates electron transfer, C vacancy formation, and M migration, driving RMSI.
• The L1₂-Pt₃Ti-TiC catalyst demonstrated exceptional activity for acidic methanol oxidation reaction (MOR), with mass activity of 2.36 A mg_Pt⁻¹ and peak power density of 187.9 mW mg_Pt⁻¹.
• DFT analysis indicated that L1₂-Pt₃Ti-TiC weakens *CO adsorption by shifting the adsorption site from Pt to Ti, enhancing MOR performance.

Conclusions:

• A reductant-free strategy effectively induces RMSI in Pt-carbide systems via gradient orbital coupling and vacancy formation.
• The resulting L1₂-Pt₃Ti-TiC intermetallic electrocatalyst exhibits state-of-the-art performance for methanol oxidation.
• The findings provide fundamental insights into RMSI mechanisms and offer a promising avenue for designing advanced electrocatalysts.