摘要
Pyrite-type sulfides(PTS)exhibit promising intrinsic activities for oxygen reduction and evolution reactions(ORR/OER).However,their poor electrical conductivities may limit the charge transfer rate to inevitably lower activity.Here,yolk-shell structured cobalt-pyrite nanospheres(CoS_(2)YSS)are prepared and modified with amino groups as nucleation sites for coupling highly-conductive needle-like nitrogendoped carbon via a facile solvothermal method(CoS_(2)YSS@NC).The as-marked CoS_(2)YSS@NC-0.5 shows a gap between yolk and shell,and an obvious exterior layer of grafted NC,which can provide an integrated structure,an interior place,and three exposed surfaces on CoS_(2).CoS_(2)YSS@NC-0.5 reveals higher ORR activity(half-wave potential of 0.88 V)and methanol resistance than commercial Pt/C.Due to in-situ formation of highly-active CoOOH,CoS_(2)YSS@NC-0.5 shows a better overpotential(244 mV at 10 mA/cm^(2))and Tafel slope(135 mV/dec)than RuO2.Zinc-air battery with CoS_(2)YSS@NC-0.5 air-cathode exhibits good open circuit potential(1.44 V),specific capacity(772.5 mAh/g)and cycling stability.Needle-like NC layer coated on the yolk-shell structure of CoS_(2)effectively lowers the charge transfer resistance to obtain extraordinary ORR/OER activities.It indicates that the integration of highly-conductive carbon onto pyritetype sulfides is an effective strategy to acquire durable bifunctional ORR/OER catalysts.
基金
the support by National Natural Science Foundation of China(Nos.52070074 and 21806031)
Outstanding Youth Fund of Heilongjiang Province(No.JQ2022E005)
LongJiang Scholars Program(No.Q201912)
Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.HC202144)
Graduate Student Innovation Research Projects of Heilongjiang University(No.YJSCX2022-219HLJU)。