Recent Advances in 0D Ni/Co-based Hollow Electrocatalysts for Electrochemical Water Splitting

Electrochemical water splitting using renewable energy sources has been recognized as a sustainable way to produce hydrogen energy due to the characteristics of low-carbon and no pollution.However,the slow hydrogen/oxygen evolution reactions(HER/OER)seriously hinder the practical application of large-scale water splitting.In this paper,the 0D Ni/Co-based hollow material is discussed in detail because of adjustable morphology,low mass density and abundant active sites,which provides an effective solution for improving the HER/OER reaction kinetics.The synthesis methods of hollow materials,such as hard template,soft template and self-template are introduced.Afterward,catalysts with different structural designs of hollow structures are reviewed,including hollow single-shelled structure,hollow core-shelled structure,hollow double-shelled structure and hollow multi-shelled structure(HoMS)catalysts.Wherein,the research progress of the 0D Ni/Co-based HoMS electrocatalysts in recent years and their prominent performances in water splitting are highlighted.Finally,the challenges and development prospects of designing Ni/Co-based HoMS catalysts in water splitting in the future are discussed.

Design and Construction of 3D Porous Na3V2(PO4)3/C as High Performance Cathode for Sodium Ion Batteries

An easy and delicate approach using cheap carbon source as conductive materials to construct 3D sequential porous structural Na3V2(PO4)3/C(NVP/C)with high performance for cathode materials of sodium ion battery is highly desired.In this paper,the NVP/C with 3D sequential porous structure is constructed by a delicate approach named as“cooking porridge”including evaporation and calcination stages.Especially,during evaporation,the viscosity of NVP/C precursor is optimized by controlling the adding quantity of citric acid,thus leading to a 3D sequential porous structure with a high specific surface area.Furthermore,the NVP/C with a 3D sequential porous structure enables the electrolyte to interior easily,providing more active sites for redox reaction and shortening the diffusion path of electron and sodium ion.Therefore,benefited from its unique structure,as cathode material of sodium ion batteries,the 3D sequential porous structural NVP/C exhibits high specific capacities(115.7,88.9 and 74.4 mA·h/g at current rates of 1,20 and 50 C,respectively)and excellent cycling stability(107.5 and 80.4 mA·h/g are remained at a current density of 1 C after 500 cycles and at a current density of 20 C after 2200 cycles,respectively).