A kind of novel uniform monodispersed three-dimensional dendritic mesoporous silica nanospheres (3D-dendritic MSNSs) has been successfully synthesized for the first time. The 3D-dendritic MSNSs can have hierarchical mesostructure with multigenerational, tunable center-radial, and dendritic mesopore channels. The synthesis was carried out in the heterogeneous oil-water biphase stratification reaction system, which allowed the self-assembly of reactants taking place in the oil-water interface for one-pot continuous interfacial growth. The average pore size of each generation for the 3D-dendritic MSNSs can be adjusted from 2.8 to 13 nm independently, which can be controlled by the varied hydrophobic solvents and concentration of silica source in the upper oil phase. The thickness of each generation can be tuned from ∼ 5 to 180 nm as desired, which can be controlled by the reaction time and amount of silica source. The biphase stratification approach can also be used to prepare other core-shell and functional mesoporous materials such as Au nanoparticle@3D-dendritic MSNS and Ag nanocube@3D-dendritic MSNS composites. The 3D-dendritic MSNSs show their unique advantage for protein loading and releasing due to their tunable large pore sizes and smart hierarchical mesostructures. The maximum loading capacity of bovine β-lactoglobulin with 3D-dendritic MSNSs can reach as high as 62.1 wt % due to their large pore volume, and the simulated protein releasing process can be tuned from 24 to 96 h by flexible mesostructures. More importantly, the releasing rates are partly dependent on the hierarchical biodegradation, because the 3D-dendritic MSNSs with larger pore sizes have faster simulated biodegradation rates in simulated body fluid. The most rapid simulated biodegradation can be finished entirely in 24 h, which has been greatly shortened than two weeks for the mesoporous silica reported previously. As the inorganic mesoporous materials, 3D-dendritic MSNSs show excellent biocompatibility, and it would have a hopeful prospect in the clinical applications.

Structural phase transitions can be used to alter the properties of a material without adding any additional elements and are therefore of significant technological value. It was found that the hexagonal-SnS2 phase can be transformed into the orthorhombic-SnS phase after an annealing step in an argon atmosphere, and the thus transformed SnS shows enhanced sodium-ion storage performance over that of the SnS2, which is attributed to its structural advantages. Here, we provide the first report on a SnS@graphene architecture for application as a sodium-ion battery anode, which is built from two-dimensional SnS and graphene nanosheets as complementary building blocks. The as-prepared SnS@graphene hybrid nanostructured composite delivers an excellent specific capacity of 940 mAh g(-1)and impressive rate capability of 492 and 308 mAh g(-1) after 250 cycles at the current densities of 810 and 7290 mA g(-1), respectively. The performance was found to be much better than those of most reported anode materials for Na-ion batteries. On the basis of combined ex situ Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and ex situ X-ray diffraction, the formation mechanism of SnS@graphene and the synergistic Na-storage reactions of SnS in the anode are discussed in detail. The SnS experienced a two-structural-phase transformation mechanism (orthorhombic-SnS to cubic-Sn to orthorhombic-Na3.75Sn), while the SnS2 experienced a three-structural-phase transformation mechanism (hexagonal-SnS2 to tetragonal-Sn to orthorhombic-Na3.75Sn) during the sodiation process. The lesser structural changes of SnS during the conversion are expected to lead to good structural stability and excellent cycling stability in its sodium-ion battery performance. These results demonstrate that the SnS@graphene architecture offers unique characteristics suitable for high-performance energy storage application.

Recent research progresses on high performance anode materials for high-energy sodium-ion batteries are comprehensively summarized.

The electrochemical CO2 reduction reaction (CO2RR) is of great importance to tackle the rising CO2 concentration in the atmosphere. The CO2RR can be driven by renewable energy sources, producing precious chemicals and fuels, with the implementation of this process largely relying on the development of low‐cost and efficient electrocatalysts. Recently, a range of heterogeneous and potentially low‐cost single‐atom catalysts (SACs) containing non‐precious metals coordinated to earth‐abundant elements have emerged as promising candidates for the CO2RR. Unfortunately, the real catalytically active centers and the key factors that govern the catalytic performance of these SACs remain ambiguous. Here, this ambiguity is addressed by developing a fundamental understanding of the CO2RR‐to‐CO process on SACs, as CO accounts for the major product from CO2RR on SACs. The reaction mechanism, the rate‐determining steps, and the key factors that control the activity and selectivity are analyzed from both experimental and theoretical studies. Then, the synthesis, characterization, and the CO2RR performance of SACs are discussed. Finally, the challenges and future pathways are highlighted in the hope of guiding the design of the SACs to promote and understand the CO2RR on SACs.

The development of a simple and reproducible route to prepare uniform core@TiO(2) structures is urgent for realizing multifunctional responses and harnessing multiple interfaces for new or enhanced functionalities. Here, we report a versatile kinetics-controlled coating method to construct uniform porous TiO(2) shells for multifunctional core-shell structures. By simply controlling the kinetics of hydrolysis and condensation of tetrabutyl titanate (TBOT) in ethanol/ammonia mixtures, uniform porous TiO(2) shell core-shell structures can be prepared with variable diameter, geometry, and composition as a core (e.g., α-Fe(2)O(3) ellipsoids, Fe(3)O(4) spheres, SiO(2) spheres, graphene oxide nanosheets, and carbon nanospheres). This method is very simple and reproducible, yet important, which allows an easy control over the thickness of TiO(2) shells from 0 to ~25, ~45, and ~70 nm. Moreover, the TiO(2) shells possess large mesoporosities and a uniform pore size of ~2.5 nm, and can be easily crystallized into anatase phase without changing the uniform core-shell structures.

Despite the high theoretical capacity of the sodium-sulfur battery, its application is seriously restrained by the challenges due to its low sulfur electroactivity and accelerated shuttle effect, which lead to low accessible capacity and fast decay. Herein, an elaborate carbon framework, interconnected mesoporous hollow carbon nanospheres, is reported as an effective sulfur host to achieve excellent electrochemical performance. Based on in situ synchrotron X-ray diffraction, the mechanism of the room temperature Na/S battery is proposed to be reversible reactions between S and NaS, corresponding to a theoretical capacity of 418 mAh g. The cell is capable of achieving high capacity retention of ∼88.8% over 200 cycles, and superior rate capability with reversible capacity of ∼390 and 127 mAh g at 0.1 and 5 A g, respectively.

The rational design and controllable synthesis of strongly coupled inorganic/graphene hybrids represents a long-standing challenge for developing advanced catalysts and energy-storage materials. Here, we report a simple sol-gel method toward creating ultradispersed TiO2 nanoparticles on graphene with an unprecedented degree of control based on the precise separation and manipulation of nanoparticles nucleated, grown, anchored, and crystallized and the reduction of graphene oxide (GO). The hybrid materials show ultradispersed anatase nanoparticles (~5 nm), ultrathin thickness (≤3 layers), and a high surface area of ~229 m(2)/g and exhibit a high specific capacity of ~94 mA h g(-1) at ~59 C, which is twice as that of mechanically mixed composites (~41 mA h g(-1)), demonstrating the potential of strongly synergistic coupling effects for advanced functional systems.

Smart surface coatings of silicon (Si) nanoparticles are shown to be good examples for dramatically improving the cyclability of lithium-ion batteries. Most coating materials, however, face significant challenges, including a low initial Coulombic efficiency, tedious processing, and safety assessment. In this study, a facile sol-gel strategy is demonstrated to synthesize commercial Si nanoparticles encapsulated by amorphous titanium oxide (TiO ), with core-shell structures, which show greatly superior electrochemical performance and high-safety lithium storage. The amorphous TiO shell (≈3 nm) shows elastic behavior during lithium discharging and charging processes, maintaining high structural integrity. Interestingly, it is found that the amorphous TiO shells offer superior buffering properties compared to crystalline TiO layers for unprecedented cycling stability. Moreover, accelerating rate calorimetry testing reveals that the TiO -encapsulated Si nanoparticles are safer than conventional carbon-coated Si-based anodes.