Highly Efficient Au ₁ Pd Single‐Atom Alloy Catalyzing Reversible Formate/Bicarbonate Interconversion: Proof‐of‐Concept for Formate‐Salt Cavern Hydrogen Storage

ABSTRACT

Reversible hydrogen storage via formate/bicarbonate cycles is a promising strategy for large‐scale hydrogen storage, while the lack of highly efficient catalysts for reversible interconversion remains a critical bottleneck. Herein, we report an amine‐modified activated carbon‐supported Au ₁ Pd single‐atom alloy (SAA) catalyst (Au ₁ Pd ₂₀ /AC‐NH) as the key breakthrough to address this challenge, and further demonstrate its proof‐of‐concept application in a novel “Formate‐Salt Cavern Hydrogen Storage System”. Featuring atomically dispersed Au promoters anchored on Pd nanoparticles, Au ₁ Pd ₂₀ /AC‐NH boosts Pd's intrinsic activity remarkably. Under near‐ambient conditions, it exhibits exceptional turnover frequencies (TOFs, based on total active metal) of 4568 h ⁻¹ for dehydrogenation (80°C, 1 bar, 1 M HCOOK) and 77 h ⁻¹ for hydrogenation (30°C, 1 bar, 1.5 M KHCO ₃ ). Specifically, in the formate dehydrogenation reaction, the Au ₁ Pd ₂₀ /AC‐NH catalyst exhibits a 45% higher initial TOF value at a conversion of 20% compared with monometallic Pd/AC‐NH; meanwhile, its hydrogenation activity is increased by 34%. These values are among the highest reported under similar reaction conditions. Mechanistic analysis reveals that the superior catalytic performance stems from the Au ₁ Pd SAA effect and synergistic interaction with surface ─NH─ groups, which collectively facilitate H ₂ dissociation and reactant adsorption. By establishing an efficient catalytic strategy and providing critical proof‐of‐concept, this work paves a viable pathway for large‐scale hydrogen storage.