Lattice confined Ru single sites in hollow Co9S8 polyhedron triggering Co-S-Ru catalytic centers for rechargeable Zn-air battery

Single -atom catalysts with precise structure and tunable coordination nature provide opportunities for developing novel catalytic centers and understanding reaction mechanisms, Herein, hollow Co9S8 polyhedrons with lattice -confined Ru single atoms (RuCo9S8) are fabricated. Aberration -corrected scanning transmission electron microscopy and X-ray absorption spectroscopy verify the isolated Ru atoms are confined in Co9S8 to form Co-S-Ru catalytic centers. Theoretical calculations indicate that the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) energy barriers are extensively reduced, and the d -band center of Co9S8 downshifts from the Fermi level, therefore boosting the desorption of 0-containing intermediates. Consequently, the RuCo9S8 exhibits an ultralow overpotential of 163 mV at 10 mA"cm-2 for OER and could catalyze a rechargeable Zn-air battery with a high -power density of 92.0 m1/1/-cm -2. This work provides a promising approach for designing novel bifunctional catalytic active centers for energy conversion.