Geminal Synergy in Pt–Co Dual-Atom Catalysts: From Synthesis to Photocatalytic Hydrogen Production

Abstract

Dual-atom catalysts (DACs) have garnered significant interest due to their high atom utilization and synergistic catalysis. However, developing a precise synthetic method for DACs and comprehending the underlying catalytic mechanisms remain challenging. In this study, we employ a photoinduced anchoring strategy to precisely synthesize PtCo DAC on graphitic carbon nitride (CN). A Co atom was anchored on CN through the lone-pair electrons of nitrogen. Upon light irradiation, photoelectrons gathering at the Co site can anchor Pt metal ions nearby, accurately facilitating the formation of heteronuclear DACs. The PtCo DAC demonstrates a remarkably high H₂ generation rate from ammonia borane (AB) hydrolysis, with a TOF of 3130 mol_H2 mol_Pt^–1 min^–1 at 298 K. This TOF value is approximately 3.2 times higher than that of the Pt single-atom photocatalyst. Importantly, the PtCo DAC shows good stability, achieving a turnover number as high as 307,982 mol_H2 mol_Pt^–1 at room temperature. The experimental and theoretical calculation results demonstrate that the synergy between Pt and Co optimizes the adsorption energy of AB and H₂ molecules while reducing the energy barrier of the rate-determining step, thus accelerating H₂ evolution from AB hydrolysis. Additionally, the introduced Co species stabilize the Pt active sites by enhancing the stability of the Pt–N bond, preventing leaching, aggregation, and deactivation. The excellent catalytic performance, good stability, and low cost of the catalysts in this work open new prospects for their practical application in hydrogen production.