Bo Wang,Jianping Yan,Yufei Zhang,Minghui Ye,Yang Yang,Cheng Chao Li
Aqueous zinc-ion batteries (ZIBs) have attracted significant attention due to their intrinsic safety, cost-effectiveness, and environmental friendliness. However, the common zinc metal anode suffers from zinc dendrite formation, self-corrosion, and surface passivation, which impede the further application of aqueous ZIBs. Herein, carbon-inserted molybdenum dioxide (MoO 2 ) materials with laminated structure are designed as novel intercalation-type anodes for ZIBs by combination of interlayer engineering and in situ carbonization of aniline guest in molybdenum trioxide interlayers. The uniform dispersion of carbon layers in laminated MoO 2 not only provide fast transportation paths for electron but also strengthen the framework of MoO 2 , leading to high structural integration during high-rate cycling. Benefiting from the unique structural design, the carbon-inserted MoO 2 electrode exhibits high initial Coulombic efficiency, excellent cycling stability, and outstanding rate capability. Multiple ex situ characterizations reveal its excellent electrochemical stability is derived from reversible intercalation mechanism and ultrastable structural framework. Furthermore, the rocking-chair zinc-ion full battery assembled with the zinc pre-intercalated Na 3 V 2 (PO 4 ) 2 O 2 F cathode presents excellent stability and ultralong lifespan with a high capacity retention of 91% over 8000 cycles.
Yuwei Ma,Guangtong Hai,Dimberu G. Atinafu,Wenjun Dong,Rongjie Li,Changmin Hou,Ge Wang
Carbon -MoS 2−x @CdS (C-MoS 2−x @CdS) core-shell nanostructures with controlled surface sulfur (S) vacancies were prepared via a glucose assisted hydrothermal growth method. The glucose acted as a reducing agent of C-MoS 2−X to partially reduce Mo 4+ ions to Mo 3+ and served as a carbon source to insert the amorphous carbon into the layered MoS 2−X simultaneously. The presence of Mo 3+ result in the surface S-vacancies, which can provide more additional active sites and enhance the photocatalytic performance. Moreover, the inserted carbon in layered MoS 2−X enhanced the electron mobility and decreased the resistance electron transfer. Density functional theory (DFT) calculation confirmed that the surface S-vacancies and the amorphous carbon increase the projected density of states at the conduct band edge, which could enhance the photo-absorption and photo-responsibility. The result is consistent with the photocatalytic H 2 production experiment . C2-10%MoS 2−x @CdS presented a high H 2 evolution rate of 61,494 μmol h −1 g −1 under visible light irrigation (λ ≥ 420 nm), which is 1.98 times and 158 times higher than that of sample without S-vacancies (10%MoS 2 @CdS) and pure CdS, respectively.
Integration of adequate activity, stability, and productivity in a catalyst is of strategical importance to achieve high performance, particularly for inactive reactants, e.g., CO2. Here, using a reversed microemulsion method, ultrafine metallic Ag nanoparticles coated with porous SiO2 can be facilely obtained using micelles as separated nanoreactors for the preparation. Such architectures allowed the rigid SiO2 matrices to act as physical spacers, so that aggregation of the Ag particles could be avoided. Meanwhile, due to the templating effect from the surfactant, large mesopores could be induced in the SiO2 shell, and thus the diffusion barrier of reactants could be minimized. When used as a heterogeneous catalyst for carboxylation of terminal alkynes by CO2 under mild conditions, the prepared xAg@SiO2 catalysts showed extraordinary performance in terms of excellent activity, stability, productivity, and wide substrate scope. The knowledge developed here may also enrich the toolbox for performance promotion of metal catalysts via specially fabricated structures.
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