Boosting oxygen electrocatalysis by chlorine-mediated microenvironment modulating and surface concave tailoring in...

Dual single-atom catalysts (DACs) represent a promising frontier in the field of electrocatalysis. However, the precise construction of DACs with modulated microenvironment to enhance oxygen electrocatalytic activities remains a formidable challenge. In present work, we report a chlorine-mediated strategy to manipulate the microenvironment of dual atomic iron sites, which are anchored on carbon nanocages with surface curvature (Fe-DSA-Cl/SCNC). Theoretical calculation results reveal that the chlorine atom modulates the local microenvironment of iron dual atom sites, decreases the energy barrier, and adjusts the oxygen adsorption/desorption capability, resulting in the enhanced electrocatalytic activities. Finite element analysis (FEA) modeling results demonstrate the hollow carbon nanocage with surface curvature regulates the local electric field, improves the mass transfer, and accelerates oxygen reaction kinetics. Benefitting from both aspects of advantages, the Fe-DSA-Cl/SCNC catalyst exhibits the excellent oxygen catalytic properties with a high half-wave (E_1/2) potential of 0.926 V in alkaline condition and a peak power density of 289 mW cm^-2 in full Zn-air battery (ZABs). Furthermore, the quasi-solid-state Zn-air batteries operates smoothly over a wide range of temperature and achieves a high stability during long-term and low-temperature cycling. Therefore, this work gives a new insight into the local microenvironment modulation and spatial configuration engineering in dual atomic sites for enhanced catalytic properties. Moreover, it also gives a new clue to design and fabrication of oxygen electrocatalysts for different working conditions.