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

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.