Coupling Ni Single Atomic Sites with Metallic Aggregates at Adjacent Geometry on Carbon Support for Efficient Hydrogen Peroxide Electrosynthesis.

Single atomic catalysts have shown great potential in efficiently electro-converting O 2 to H 2 O 2 with high selectivity. However, the impact of coordination environment and introduction of extra metallic aggregates on catalytic performance still remains unclear. Herein, first a series of carbon-based catalysts with embedded coupling Ni single atomic sites and corresponding metallic nanoparticles at adjacent geometry is synthesized. Careful performance evaluation reveals Ni SA /Ni NP -NSCNT catalyst with precisely controlled active centers of synergetic adjacent Ni-N 4 S single sites and crystalline Ni nanoparticles exhibits a high H 2 O 2 selectivity over 92.7% within a wide potential range (maximum selectivity can reach 98.4%). Theoretical studies uncover that spatially coupling single atomic NiN 4 S sites with metallic Ni aggregates in close proximity can optimize the adsorption behavior of key intermediates * OOH to achieve a nearly ideal binding strength, which thus affording a kinetically favorable pathway for H 2 O 2 production. This strategy of manipulating the interaction between single atoms and metallic aggregates offers a promising direction to design new high-performance catalysts for practical H 2 O 2 electrosynthesis.