Well‐crystallized Nb‐doped anatase TiO2 nanoparticles are prepared by a novel synthetic route and successfully used as the photoanode of dye‐sensitized solar cells (DSSCs). The homogenous distribution of Nb in the TiO2 lattice is confirmed by scanning transmission electron microscopy (STEM) elemental mapping and line‐scanning analyses. After Nb doping, the conductivity of the TiO2 powder increases, and its flat‐band potential (Vfb) has a positive shift. The energy‐conversion efficiency of a cell based on 5.0 mol% Nb‐doped TiO2 is significantly better, by about 18.2%, compared to that of a cell based on undoped TiO2. The as‐prepared Nb‐doped TiO2 material is proven in detail to be a better photoanode material than pure TiO2, and this new synthetic approach using a water‐soluble precursor provides a simple and versatile way to prepare excellent photoanode materials.

The polyhedral CoS(2) with a narrow size distribution was synthesized by a facile solid-state assembly process in a sealed silica tube. The flux of potassium halide (KX; X = Cl, Br, I) plays a crucial role in the formation of polyhedrons and the size distribution. The S(2)(2-) groups in CoS(2) can be controllably withdrawn during heat treatment in air. The obtained phases and microstructures of CoS(2), Co(3)S(4), CoS, Co(9)S(8), and CoO depended on heating temperature and time. These cobalt materials, successfully used as the electrodes of lithium ion batteries, possessed good cycling stability in lithium ion batteries. The discharge capacities of 929.1 and 835.2 mAh g(-1) were obtained for CoS(2) and CoS respectively, and 76% and 71% of the capacities remained after 10 cycles. High capacities and good cycle performance make them promising candidates for lithium ion batteries. The approach combining solid-state assembly and heat treatment provides a simple and versatile way to prepare various metal chalcogeides for energy storage applications.

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Band structure design plays a vital role on the development of highly efficient and visible-light driven photocatalysts. Large band dispersions ensure a fair mobility of the photoinduced charge carriers, leading to excellent photocatalysis. As a case in point, Bi 2 Sn 2 O 7 has been investigated for the first time as a robust visible-light photocatalyst. The VB and CB are both highly dispersed, and contain s orbitals (Bi 6p + Sn 5s + O 2p for CB, O 2p + Bi 6s for VB). Bi 2 Sn 2 O 7 was prepared by a direct hydrothermal reaction in the absence of additives and exhibited improved performance. This study not only discloses insights into the design of new photocatalysts in term of band engineering, but also provides flexibility and selectivity for the deliberate synthesis of other functional materials.

Nano silver particles loaded on micrometer-size TiO2, nanosize TiO2, and BiVO4 were prepared by a silver mirror reaction (SMR), which is an old and well-known method. Morphology of silver on the surface of semiconductor particles was characterized by energy dispersion spectrum, transmission electron microscopy, and electron backscatter diffraction. The photocatalytic activities of these photocatalysts were evaluated by the degradation of methyl orange and hydrogen production under UV and visible light irradiation, respectively. The experimental results indicated that the photocatalytic activities of Ag/TiO2 and Ag/BiVO4 composites prepared by the SMR were remarkably higher than those prepared by the photoinduced deposition method.

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