Bridging Acidic and Alkaline Hydrogen Electrocatalysis via Ru‐Modified Pt ₃ Co for Waste‐to‐Energy Electrochemical Neutralization Fuel Cells

The hydrogen oxidation (HOR) and hydrogen evolution (HER) reactions define the core of hydrogen electrochemistry, yet demand distinct control over hydroxyl binding and interfacial water structuring. Here, we engineer a ruthenium single-atom anchored Pt₃Co intermetallic on nitrogen-doped carbon (O-Pt₃Co-RuNC) to bridge this divide. The catalyst delivers a mass activity 4.1 times higher than Pt/C for alkaline HOR with only 9.3% CO-induced loss, while simultaneously exhibiting remarkable activity for acidic HER, thus establishing a rare cross-environment bifunctional platform. Leveraging this property, we design an electrochemical neutralization energy fuel cell (ENFC) that converts acid-base neutralization energy directly into electricity. Using O-Pt₃Co-RuNC as both anode and cathode catalyst, the ENFC achieves a peak power density of 75.0 mW cm^- ² and stable operation beyond 400 h while simultaneously neutralizing waste acid and alkali. Operando spectroscopy and theoretical analyses reveal that Ru atoms electronically reprogram adjacent Co sites, strengthening hydrogen bonding in interfacial water and accelerating proton-coupled electron transfer. This study offers a blueprint for constructing hydrogen electrocatalysts and hybrid fuel cells that harmonize activity, durability, and sustainable resource utilization.