Electron and configuration engineering of atomic Cu and multioxidated Cu_(2+1)O centers via gasifiable reductant strategy for efficient oxygen reduction toward Zn-air battery

Efforts in a large number of transition metal-carbon systems are devoted to the development of efficient catalysts for oxygen reduction reaction(ORR).However,unsatisfied O_(2)adsorption and slow reduction of OH*at the active centers hinder the further development of these catalysts.We here report a gasifiable reductant strategy,of which a new Cu-based metal organic framework(MOF:termed NTU-83)nanosheet was co-pyrolyzed with melamine to produce the N-coordinated atomic Cu and multi-oxidated Cu_(2+1)O active centers on the carbon foam with ultrathin skeleton.The engineered electrons and configuration of the active centers boost the catalyst(Cu/NC-1000)to show superior ORR activity(E_(1/2)=0.85 V),excellent stability,and methanol resistance.Further modeling calculation and controlled experiments reveal that the Cu_(2+1)O species play a crucial role in kinetically accelerated adsorption and activation of O_(2),while the N_(4)coordinated atomic Cu facilitates fast reduction of OH*.Such characteristics endow the Zn-air battery that containing Cu/NC-1000 as air cathode to show a high peak power density(138 mW·cm^(−2)),a high specific capacity of 763 mAh·gZn^(−1),and outstanding long-term cycle stability.The plausible mechanism and excellent performance show that gasifiable reductant strategy opens up a new route for regulation of the electronic of active sites but also provides a candidate for the practical application in energy conversion/storage devices.