Noncovalent Assembly Strategy for Efficient Synthesis of Dual-Atom Catalysts

Diatomic catalysts (DACs), as a frontier of research on atomically dispersed catalysts, have drawn great attention, especially in electrocatalysis. However, most of the current synthetic strategies for DACs suffer from poor efficiency and high cost. In this work, a novel noncovalent assembly strategy is reported for the efficient synthesis of DACs. By the aid of two kinds of noncovalent intermolecular force, the π–π stacking and Coulomb forces, a pair of metal complex ions with opposite electrical charges is spontaneously loaded onto the carbon substrate and transformed into diatomic sites via thermal treatment. This noncovalent assembly approach shows universal feasibility for a broad spectrum of DACs (Ir–Fe, Pt–Fe, Pt–Co, and Pt–Ni). To prove the practical utility, the as-prepared PtFe-DAC is deployed as oxygen reduction reaction catalyst, performing excellent activity with a half-wave potential of 0.935 V (vs RHE) and a 2.3 times higher turnover frequency than that of the single-atomic Fe-SAC. In situ characterization and theoretical calculation indicate that the adjacent Pt sites could endow moderate activation of oxygen molecule on Fe sites by lowering the electron pairing energy as well as the modulation of the d-band center and spin states of Fe centers propelling the desorption of the intermediates.