An Efficient PdPt/rGO Catalyst for Hydrogen Electrolysis in Acidic Medium: Structure‐Activity Relationships and CO‐Tolerance

The reliable conversion and utilization of green hydrogen are often hindered by carbon monoxide (CO) impurities, which strongly poison conventional platinum catalysts in acidic media. To address this challenge, we developed PdPt alloys supported on reduced graphene oxide (PdPt/rGO) with controlled Pd:Pt ratios and investigated their activity toward the hydrogen oxidation (HOR) and hydrogen evolution reactions (HER). Structural analyses (PXRD, TEM, XPS, CO‐DRIFTS, H 2 ‐D 2 exchange) confirmed alloy formation, lattice strain, and electronic interactions between Pd and Pt, resulting in a downshifted d‐band center. These modifications weaken hydrogen and CO binding, leading to enhanced activity and CO tolerance. Among the series, Pd3Pt1/rGO showed the most balanced performance, delivering higher current densities and lower Tafel slopes than monometallic Pd/rGO and Pt/rGO, with activity comparable to commercial Pt/C. The results highlight that minimal Pt incorporation into Pd‐based catalysts effectively tunes the electronic structure, enabling reversible HOR/HER catalysis in acidic environments. This study provides a rational design approach for developing efficient, CO‐tolerant electrocatalysts to advance hydrogen energy technologies.