Interfacial Dual-Electric-Field-Mediated SnO ₂ –Pt Hollow Nanotubes Enhance Hydrogen Oxidation Activity and Phosphoric Acid Tolerance

Phosphoric acid (PA) poisoning severely compromises Pt-based catalysts in high-temperature proton exchange membrane fuel cells (HT-PEMFCs) through irreversible adsorption on active sites. We address this challenge by engineering SnO₂ hollow nanotubes anchored with ultradispersed Pt nanoclusters (denoted as Pt/SnO₂, Pt:3.7 wt %), creating interfacial dual-electric fields that synergistically modulate reactant adsorption. Combined experimental and theoretical studies reveal charge redistribution via Pt to SnO₂ electron transfer optimizes hydrogen adsorption (ΔG_H⁺ = -0.30 eV) while enabling selective PA anchoring on SnO₂, reducing phosphate adsorption energy on Pt sites by 4.15 eV versus commercial Pt/C. This strategic design preserves Pt's H-intermediate processing capability, yielding exceptional hydrogen oxidation reaction (HOR) performance: dynamic current density of 19.81 mA cm^-2, mass activity of 2.45 A mg_Pt^-1, and 3.5-fold stability improvement in concentrated H₃PO₄. The catalyst maintains 94.6% initial activity after 10,000 cycles, surpassing Pt/C's rapid degradation. Our work establishes electric field-mediated adsorption engineering as a universal strategy for developing acid-tolerant electrocatalysts in advanced energy systems.