Construction of amorphous SiO2 modified ß-Bi2O3 porous hierarchical microspheres for photocatalytic antibiotics degradation.

This work describes the synthesis of porous hierarchical microspheres composed of amorphous SiO2 and crystalline ß-Bi2O3 (BSO) via a simple solvothermal process and subsequent calcination. Complementary physicochemical methods were applied to study the function of amorphous SiO2, as well as the phase composition and morphology evolution of as-synthesized samples as a function of calcination temperature. The presence of amorphous SiO2 contributed to form hierarchically structured ß-Bi2O3 with enhanced thermostability. Moreover, the degradation of tetracycline hydrochloride (TC) under visible light irradiation was employed as a model reaction to evaluate the photocatalytic activity of as prepared materials. In consequence, both phase composition and morphology were found to be significant parameters for adjusting the photocatalytic performance of the synthesized samples. The fastest TC degradation at a low dosage of catalyst (0.2 g L-1) was observed for the sample annealed at 400℃ which contains a highly crystalline ß-Bi2O3 phase. The synergistic effect of the porous structure, excellent light absorption, and higher charge carrier separation and transfer efficiency is believed to be the reason for the optimal photocatalytic activity. This study offers a new method toward the fabrication of hierarchical porous structured ß-Bi2O3 with enhanced thermostability for various applications.

Construction of Hierarchical MoSe2 Hollow Structures and Its Effect on Electrochemical Energy Storage and Conversion.

Metal selenides have attracted increased attention as promising electrode materials for electrochemical energy storage and conversion systems including metal-ion batteries and water splitting. However, their practical application is greatly hindered by collapse of the microstructure, thus leading to performance fading. Tuning the structure at nanoscale of these materials is an effective strategy to address the issue. Herein, we craft MoSe2 with hierarchical hollow structures via a facile bubble-assisted solvothermal method. The temperature-related variations of the hollow interiors are studied, which can be presented as solid, yolk-shell, and hollow spheres, respectively. Under the simultaneous action of the distinctive hollow structures and interconnections among the nanosheets, more intimate contacts between MoSe2 and electrolyte can be achieved, thereby leading to superior electrochemical properties. Consequently, the MoSe2 hollow nanospheres prepared under optimum conditions exhibit optimal electrochemical activities, which hold an initial specific capacity of 1287 mA h g-1 and maintain great capacity even after 100 cycles as anode for Li-ion battery. Moreover, the Tafel slope of 58.9 mV dec-1 for hydrogen evolution reaction is also attained.

Generalized Synthesis of Ternary Sulfide Hollow Structures with Enhanced Photocatalytic Performance for Degradation and Hydrogen Evolution.

A series of ternary sulfide hollow structures have been successfully prepared by a facile glutathione (GSH)-assisted one-step hydrothermal route, where GSH acts as the source of sulfur and bubble template. We demonstrate the feasibility and versatility of this in situ gas-bubble template strategy by the fabrication of novel hollow structures of MIn2S4 (M = Cd, Zn, Ca, Mg, and Mn). Interestingly, with the reaction time varying, the hierarchical CdIn2S4 microspheres with controlled internal structures can be regulated from yolk-shell, smaller yolk-shell (yolk-shell with shrunk yolk), hollow, to solid. Under visible-light irradiation, all of our prepared CdIn2S4 samples with different morphologies were photoactivated. In virtue of the appealing hierarchical hollow structure, the yolk-shell-structured CdIn2S4 microspheres exhibited the optimal photocatalytic activity and excellent durability for both the X3B degradation and H2 evolution, which can be ascribed to the synergy-promoting effect of the small crystallite size together with the unique structural advantages of the yolk-shell structure. Thus, we hypothesize that this proof-of-concept strategy paves an example of rational design of hollow structured ternary or multinary sulfides with superior photochemical performance, holding great potential for future multifunctional applications.