Three-Dimensional Graphene-Supported Ni3Fe/Co9S8 Composites: Rational Design and Active for Oxygen Reversible Electrocatalysis
Hu, XJ (Hu, Xuejiao)[ 2 ] ; Huang, T (Huang, Tan)[ 1 ] ; Tang, YW (Tang, Yawen)[ 2 ]*（唐亚文）; Fu, GT (Fu, Gengtao)[ 1 ]*; Lee, JM (Lee, Jong-Min)[ 1 ]*
[ 1 ] Nanyang Technol Univ, Sch Chem & Biomed Engn, Singapore 637459, Singapore
[ 2 ] Nanjing Normal Univ, Sch Chem & Mat Sci, Jiangsu Collaborat Innovat Ctr Biomed Funct Mat, Jiangsu Key Lab New Power Batteries, Nanjing 210023, Jiangsu, Peoples R China
ACS APPLIED MATERIALS & INTERFACES，201901,11(4),4028-4036
The development of low-cost and efficient electrocatalysts with a bicomponent active surface for reversible oxygen electrode reactions is highly desirable and challenging. Herein, we develop an effective calcination-hydrothermal approach to fabricate graphene aerogelanchored Ni3Fe-Co9S8 bifunctional electrocatalyst (Ni3Fe-Co9S8/rGO). The mutually beneficial Ni3Fe-Co9S8 bifunctional active components efficiently balance the performance of oxygen reduction and oxygen evolution reactions (ORR/OER), in which Co9S8 promotes the ORR and Ni3Fe facilitates the OER This balance behavior has an obvious advantage over that of monocomponent Ni3Fe/rGO and Co9S8/rGO catalysts. Meanwhile, the additional synergy between porous rGO aerogels and Ni3Fe-Co9S8 endows the composite with more exposed active sites, faster electrons/ions transport rate, and better structural stability. Benefiting from the reasonable material selection and structural design, the Ni3Fe-Co9S8/rGO exhibits not only outstanding ORR activity with the high onset- and half-wave potentials (E-onset = 0.91 V and E-1/2 = 0.80 V) but also satisfactory OER activity with a low overpotential at 10 mA cm(-2) (0.39 V). Moreover, rechargeable Zn-air cells equipped with Ni3Fe-Co9S8/rGO exhibit excellent rechargeability and a fast dynamic response.