Highly efficient Co3O4/Co@NCs bifunctional oxygen electrocatalysts for long life rechargeable Zn-air batteries

Synthesis of Ultrasmall NiCo2O4 Nanoparticle-Decorated N-Doped Graphene Nanosheets as an Effective Catalyst for Zn–Air Batteries

“…Transition metal oxides (TMOs) are considered as promising non-noble metal catalysts because of their superior electrochemical performance, plentiful reserves, and low prices. , To this end, Mn-, Co-, and Ni-based oxides have been extensively researched in recent years. , Among them, nickel–cobalt oxides (NiCo 2 O 4 ) exhibit outstanding electrocatalytic performance. − NiCo 2 O 4 in the shape of ultrasmall nanoparticles can provide lots of active sites per unit mass owing to the high specific surface areas. Nevertheless, they also have some disadvantages, such as the intrinsic inferior electrical conductivity and easy aggregation, resulting in inferior electrocatalytic activity. , To address these problems, the combination of metal oxide nanoparticles and conductive carbon substrates has been confirmed to be an effective strategy .…”

“…18−22 Transition metal oxides (TMOs) are considered as promising non-noble metal catalysts because of their superior electrochemical performance, plentiful reserves, and low prices. 23,24 To this end, Mn-, Co-, and Ni-based oxides have been extensively researched in recent years. 25,26 Among them, nickel−cobalt oxides (NiCo 2 O 4 ) exhibit outstanding electro-catalytic performance.…”

Cobalt-Nanoparticle-Decorated Cobalt–Molybdenum Bimetal Oxides Embedded in Flower-like N-Doped Carbon as a Durable and Efficient Electrocatalyst for Oxygen Evolution Reaction

“…Various non-noble transition-metal compounds, such as oxides, − and nonmetallic materials, − show excellent OER activity, which provides a potential for replacing commercial precious metal catalysts and promotes the good development of OER. Among them, cobalt, a transition metal as well as the corresponding oxide/hydroxide shows proven OER property.…”

“…The highly conductive carbon materials can be synthesized in the single step of high-temperature calcination. In addition, the metal center of MOF can be converted into metal/metal oxide during high-temperature calcination . The coupling interface between metal and metal oxide can contribute to improving the OER performance. , For example, Li and co-workers adopted polystyrene (PS) microspheres and ZIF-67 as precursors for preparing C-doped Co/Co 3 O 4 -based hollow spheres with a layered micro/nanostructure as the OER electrocatalyst, which at the current density of 10 mA·cm –2 in 1 M KOH manifested an overpotential of 352 mV .…”

Regulating the Electronic Structure and Active Sites in Ni Nanoparticles by Coating N-Doped C Layer and Porous Structure for an Efficient Overall Water Splitting

“…Transition-metal (Ni, Co, and Mn) catalysts have been developed as promising electrocatalysts for water splitting due to their excellent properties, abundance reserves, and low cost. − However, the insufficient active sites and poor chemical durability of these transition-metal catalysts hinder their electrocatalytic performance. , Recently, several strategies, such as surface engineering, , defect engineering, , heteroatoms doping, , and heterostructure fabrication, , have been attempted to develop the high-performance transition-metal-based catalysts. Among them, hybrid nanostructures composed of transition metal embedded in carbon matrix have been suggested as promising low-cost substitutes for noble-metal-based catalysts for water electrolysis. − In particular, Huang et al fabricated NiSe 2 @NC core–shell octahedrons and delivered an enhanced HER performance by changing the composition of the N-C shells; Yu et al synthesized a Co 3 O 4 /Co@NCs heterostructure as an efficient electrocatalyst for the oxygen reduction reaction . Encapsulation of metal species in the carbon shell is expected to be an efficient path to improve the intrinsic catalytic activity of transition-metal-based catalysts, which not only enables effective change in the electronic density of states around carbon by virtue of promoted electron transfer from metal atoms to carbon but also prevents the aggregation and corrosion of the metal component during the reaction. − In addition, doping of the heteroatom (such as N, S, P, etc.)…”