Hierarchical rattle-like N-doped anatase TiO₂ superstructure: one-pot synthesis, morphological evolution and superior visible light photocatalytic activity

Abstract

Morphology control and impurity doping have been considered as two potent strategies for improving the photocatalytic activity of TiO 2 photocatalysts. Here, a one-pot solvothermal method was developed for the preparation of N doped rattle-like TiO 2 with spherical mesoporous cores and hierarchical shells composed of ultrathin nanosheets to simultaneously realize those two strategies. This method involves the formation of nascent nanoparticles in a sonication treatment before the solvothermal reaction, and the morphology evolution from condensed spheres to core@shell structures, and eventually to a core@void@shell architecture, switched by the crystalline nature of the products during the solvothermal reaction. The as-prepared sample features a high surface area (258.5 m 2 g −1), abundant porous texture and a unique rattle-like structure, which allows for multiple reflections of incoming light and thus optimizes light absorption ability. The concomitant N doping helps to extend the light absorption edge to the visible light region, optimizing the utilization of solar energy. As expected, when used as a photocatalyst for degradation of Rhodamine B and formic acid under visible light irradiation, the as-prepared N doped rattle-like TiO 2 exhibited superior visphotocatalytic activity thanks to its unique structure and specific N doping.

Gas-Phase Photoelectrocatalysis for Breaking Down Nitric Oxide

“…The formation of a high-crystallinity anatase phase via annealing is necessary to improve the photocatalytic performance of the photoactive layers, resulting in an unavoidable decrease in the surface area owing to the agglomeration of TiO 2 nanoribbons. A porous structure with a large surface area and well-crystallized anatase phase is required to drive the adsorption of pollution molecules and facilitate the transfer of reactants and products in the pore channels. − The UV–vis diffuse reflectance spectra (Figure b) illustrate that after embedding CNTs, the absorption edge of CT-25 slightly shifted to a longer wavelength. The corresponding band gaps of both T and CT-25 were calculated to be approximately 3.26 and 3.19 eV, respectively, based on the Kubelka–Munk formula (Figure c).…”

Fabrication of Ellipsoidal Silica Yolk–Shell Magnetic Structures with Extremely Stable Au Nanoparticles as Highly Reactive and Recoverable Catalysts

“…Yolk–shell nanocomposites (NCs) with distinctive core@void@shell architectures have generated tremendous current research because of their outstanding advantages of structural and functional combinations, displaying fascinating potentials in heterogeneous catalysis. − More importantly, highly tailorable properties of the cores and shells impart to these modulated yolk–shell NCs great versatility to be flexibly designed for specific demands or particular catalytic performance. − And the application of yolk–shell nanostructures was considered to be a suitable support to effectively stabilize Au NPs. , It is noteworthy that the yolk–shell NCs featuring a single metal core within a hollow shell can prohibit these NPs from aggregating and deactivating to some extent. ,− Undesirably, several major defects inevitably arise from low reaction rates and difficulties in pursuing fine morphologies. ,, Alternatively, through uniformly entrapping Au NPs within both the cores and shells from modulated yolk–shell NCs, high catalyst-loading content and enhanced thermal stability can be concurrently implemented to promote their catalytic functions. ,− …”