Silver based single atom catalyst with heteroatom coordination environment as high performance oxygen reduction reaction catalyst

Ag is a potential low-cost oxygen reduction reaction(ORR)catalyst in alkaline condition,which is important for the zinc-air batteries.Here,we report that an Ag based single atom catalyst with heteroatom coordination.Ag1-h-NPClSC,has been synthesized and shown much improved performance towards ORR by manipulating the coordination environment of the Ag center.It shows a high half wave potential(0.896 V)and a high turnover frequency(TOF)(5.9 s^(−1))at 0.85 V,which are higher than the previously reported Ag based catalysts and commercial Pt/C.A zinc-air battery with high peak power density of 270 mW·cm^(−2)is fabricated by using the Ag1-h-NPClSC as air electrode.The high performance is attributed to(1)the hollow structure providing good mass transfer;(2)the single atom metal center structure providing high utility of the Ag;(3)heteroatom coordination environment providing the adjusted binding to the ORR intermediates.Density functional theory(DFT)calculations show that the energy barrier for the formation of OOH*,which is considered as the rate determine step for ORR on Ag nanoparticles,is lowered on Ag1-h-NPClSC,thus improving the ORR activity.This work demonstrates that the well manipulated Ag based single atom catalysts are promising in electrocatalysis.