A comprehensive review on oxygen vacancy modified photocatalysts including synthesis (controllability of location, content, etc. ), characterization (qualitative, quantitative and locational analysis), and applications and mechanisms.

The rational design and preparation of promising cathode electrocatalysts with excellent activity and strong stability for metal-air batteries is a huge challenge. In this work, we innovate an approach of combining solvothermal with high-temperature pyrolysis utilizing zeolitic imidazolate framework (ZIF)-8 and ZIF-67 as the template to synthesize a novel hybrid material of hierarchical porous yolk—shell Co-N-C polyhedron nanocatalysts engaged in graphene nanopocket (yolk—shell Co-N-C@GNP). The obtained catalyst exhibits prominent bifunctional electrocatalytic performance for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in the alkaline condition, in which the half-wave potential is 0.86 V for ORR, and the over-potential for OER is 0.42 V at 10 mA·cm⁻². The rechargeable aqueous Zn-air battery fabricated with yolk—shell Co-N-C@GNP cathode deliveries an open circuit voltage (OCV) of 1.60 V, a peak power density of 236.2 mW·cm⁻², and excellent cycling stability over 94 h at 5 mA·cm⁻². The quasi-solid-state Zn-air battery (ZAB) using yolk-shell Co-N-C@GNP displays a high OCV of 1.40 V and a small voltage gap of 0.88 V in continuous cycling tests at 2 mA·cm⁻². This work provides a valuable thought to focus attention on the design of high-efficient bifunctional catalysts with hierarchical porous yolk—shell framework and high-density metal active sites for metal-air battery technologies.

Synthesis, photocatalytic applications and future prospects of noble metal-modified semiconductors fabricated via photodeposition.

The current focus of research lies in the advancement of electrocatalysts based on phosphides, which exhibit exceptional features and robust stability in alkaline environments. In this study, we have successfully prepared a novel bifunctional electrocatalyst for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) by in situ phosphidation and carbonization using Co/Zn-ZIF as the template and melamine-polyphosphate (MPP) as the phosphorus source with a certain mass ratio. The resulting catalyst comprises nano-sized heterostructured particles of cobalt phosphides (a combination of Co₂P and CoP) confined in N,P-codoped porous carbon polyhedra, exhibits excellent electrocatalytic properties in alkaline media and can be utilized as an electrode material for efficient Zn–air batteries due to the exceptional properties of mixed-phase CoP@Co₂P heterostructured nanoparticles and its unique structural characteristics. The Zn–air battery demonstrates a high open-circuit voltage of 1.56 V, an outstanding peak power density of 215.1 mW cm⁻² and stable cycling over 580 hours. This study provides substantial evidence to support the feasibility of utilizing surface engineering techniques to create highly efficient bifunctional electrocatalysts for the purpose of metal–air battery applications.

Transition metal nitrides and carbides have attracted intensive attentions in metal-air battery application due to their metallic electron transport behavior and high chemical stability toward the oxygen reduction reaction (ORR). Herein, the polyoxometalate@polyaniline composite derived WN-W₂C heterostructured composite (WN-W₂C@pDC) has been fabricated through an in situ nitriding-carbonization strategy, with WN-W₂C nanoparticles implanted on N doped carbon nanorods. As-fabricated WN-W₂C@pDC demonstrates prominent electrocatalytic performance towards ORR and excellent cycling stability in metal-air battery, which possesses positive half-wave potential and large diffusion limiting current density (0.81 V and 5.8 mA·cm⁻²). Moreover, it demonstrates high peak power density of 157.4 mW·cm⁻² as Al-air primary cathode and excellent stability at the discharge—charge test (> 500 h) of Zn-air secondary battery. The excellent activity and durability of WN-W₂C@pDC catalyst should be attributed to the combined effect of intimate WN-W₂C heterointerfaces, unique embedded nanoparticles structure, and excellent electrical media of N doped carbon, confirmed by a series of contrast experiments.