Robust bifunctional oxygen electrocatalyst with a “rigid and flexible” structure for air-cathodes

Abstract

The development of highly active air-cathodes with robust stability and a low price is of crucial significance for rechargeable Zn-air batteries and remains a great challenge. Herein, for the first time, we report a "rigid and flexible" material consisting of three-dimensional (3D) porous nickel-manganese oxide (Ni 6 MnO 8) coupled with 1D ultrathin Au nanowires (Au-NWs) as an efficient bifunctional oxygen electrocatalyst, adopting α-naphthol-Au(III) as a precursor of Au-NWs and pre-formed Ni 6 MnO 8 as a support. Ni 6 MnO 8 acts not only as a robust carbon-free support that is stable in alkaline electrochemical conditions, but also as a highly active component for the oxygen evolution reaction (OER), while flexible Au-NWs contribute to the excellent oxygen reduction reaction (ORR) activity and act as a flexible conductive electronic network. The coupling of Ni 6 MnO 8 and Au-NWs plays a complementary role in the two types of oxygen electrocatalytic reactions. Accordingly, their advantages have been optimally harnessed while overcoming their deficiencies. Moreover, a Zn-air battery assembled with such a rigid and flexible air-cathode has lower charge and discharge overpotentials and a higher cyclic stability than those with a mixed Pt/C+RuO 2 catalyst.

Oxygen Vacancy–Rich In‐Doped CoO/CoP Heterostructure as an Effective Air Cathode for Rechargeable Zn–Air Batteries

“…Compared with In‐CoO/CoP NR, the In‐CoO/CoP FNS also presents superior ORR activity, indicating that porous sheet‐like structure is another factor accelerating the ORR. This character can significantly facilitate both rapid mass transport and charge transfer in comparison to nonporous catalysts . Moreover, the E 1/2 value of In‐CoO/CoP FNS is close to that of Pt/C benchmark, and superior to many other available non‐noble metal catalysts (Table S1, Supporting Information).…”

Direct Magnetic Reinforcement of Electrocatalytic ORR/OER with Electromagnetic Induction of Magnetic Catalysts

“…Since pure carbon have a charge neutral state that usually do not have catalytic activity, most research have focused on i) designing intrinsic defects including edge, vacancy, pore and topological structures; [ 17–20 ] and ii) introducing extrinsic defects such as non‐metallic atoms of N, B, F, P, etc., or metal atoms of Ni, Co, Fe, Zn, Mo, etc. [ 21–28 ] The introduction of defects increases the charge delocalization or number of edge sites of the carbon, and thus enhances the catalysis. However, some major issues still exist.…”

Immobilization of Fe-Doped Ni2P Particles Within Biomass Agarose-Derived Porous N,P-Carbon Nanosheets for Efficient Bifunctional Oxygen Electrocatalysis

“…With the concern of an ever-increasing energy demand as well as serious and intensifying environmental issues, exploring alternative renewable energy sources or energy conversion/storage technologies, instead of fossil fuels, has become more and more pressing to ensure future sustainable development (Zhao et al, 2013; Wang et al, 2015; Chen et al, 2016; Cano et al, 2018). Some examples of these are rechargeable metal-air batteries, water electrolysis and fuel cells, in which electrocatalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play pivotal and cornerstone roles (Park et al, 2016; Li et al, 2017a; Zheng et al, 2017; Fu et al, 2018a; Pan et al, 2018; Qin et al, 2018). However, both reactions have intrinsically sluggish kinetics with thermodynamic barriers and high overpotentials, originating from their complicated multielectron transfer pathways (Cheng et al, 2017; Jiang et al, 2018; Li et al, 2018a; Fu and Lee, 2019; Fu et al, 2019).…”