Methanol from CO2: For the hydrogenation of carbon dioxide, a marked increase in the methanol selectivity was observed when the reaction was catalyzed by Cu/rod‐shaped ZnO/CdSe with heterojunction structure. Diffusion reflectance, photoluminescence, and ESR spectroscopies clearly indicated an increase in the electron density because of the incorporation of CdSe in the core–shell morphology of Cu/rod‐shaped ZnO (see picture).

Nb(2)O(5) nanorods and nanospheres were synthesized, and their photocatalytic activity for methylene blue decomposition in water compared. Nb(2)O(5) nanorods clearly displayed higher activity, despite their comparable surface area. With a shape-dependent surface acidity, hydrothermal stability, and high photoactivity, these Nb(2)O(5) nanorods are a unique and exciting nanomaterial for non-classical photocatalytic mineralization of organic compounds in water.

A series of highly efficient semiconductor nanocrystal (NC) photocatalysts have been synthesized by growing wurtzite-ZnO tetrahedrons around pre-formed CdS, CdSe, and CdTe quantum dots (QDs). The resulting contact between two small but high-quality crystals creates novel CdX/ZnO heterostructured semiconductor nanocrystals (HSNCs) with extensive type-II nanojunctions that exhibit more efficient photocatalytic decomposition of aqueous organic molecules under UV irradiation. Catalytic testing and characterization indicate that catalytic activity increases as a result of a combination of both the intrinsic chemistry of the chalcogenide anions and the heterojunction structure. Atomic probe tomography (APT) is employed for the first time to probe the spatial characteristics of the nanojunction between cadmium chalcogenide and ZnO crystalline phases, which reveals various degrees of ion exchange between the two crystals to relax large lattice mismatches. In the most extreme case, total encapsulation of CdTe by ZnO as a result of interfacial alloying is observed, with the expected advantage of facilitating hole transport for enhanced exciton separation during catalysis.

The search for new low carbon and clean energy technologies is prominent on the research agendas of many governments, universities, and industrial sectors. In particular, the possibility of using solar energy for hydrogen production, fine chemicals manufacture, and water cleansing is currently under intense research. The use of semiconducting oxides, such as TiO 2 and ZnO, as photoactive materials has been receiving much attention. Recent work indicates that nanoparticles of these compounds show strong shape-dependent (surface-dependent) photocatalytic properties. [1,2] Spherical nanoparticles with high specific surface area to volume ratios are generally preferred. However, the high electron-hole recombination rate sometimes seen on their defect-rich nonplanar surfaces can be problematic. [1] As an n-type transition metal oxide semiconductor, Nb 2 O 5 has attracted a great deal of interest owing to remarkable applications in gas sensing, acid catalysis, electrochromics, field emission displays, and microelectronics. [3][4][5][6][7] Despite having high photocatalytic activity and well-documented water-tolerant acidic surfaces, at present there are few studies concerning the use of Nb 2 O 5 -based materials for photocatalytic applications. [8,9] Herein we report that the (100) surface lying along the axis of pseudo-hexagonal TT Nb 2 O 5 nanorod crystals offers enhanced photocatalytic activity over nanospheres for methylene blue decomposition in aqueous solution. We also reveal for the first time that the strong acidic sites on the exposed crystallographic planes of the nanorods readily bind methylene blue molecules from solution. In the presence of a typical radical scavenger (DMSO), Nb 2 O 5 nanorods show only a marginal decrease in decomposition rate. This is in contrast to ZnO, which adopts the classical mechanism of holeinduced hydroxyl radical attack on organic molecules in solution. The unique combination of adsorption and preconcentration of organic contaminants followed by direct surface decomposition driven by photocarriers gives rise to improved efficiency in this nonclassical mechanism for photomineralization on a Nb 2 O 5 surface.Details on materials synthesis, testing, and characterization can be found in the Supporting Information. As seen from the TEM image in Figure 1 a, Nb 2 O 5 nanospheres of 20-50 nm diameter were obtained by our precipitation method. Selected area electron diffraction (SAED) (see the Supporting Information) gave ring patterns indicative of the poor long-range crystallinity of the Nb 2 O 5 nanospheres. This is not surprising given the fact that the rapid non-equilibrium precipitation conditions do not allow for the extended growth of a particular phase. Thus, spherically shaped particles that offer a decrease in overall surface energy are anticipated. However, in the case of Nb 2 O 5 nanorod synthesis, we employed the solvothermal technique over a lengthy growth period in the presence of a structure-directing agent, oleic acid in trioctylamine. The TEM image in Figure 1 b clearl...

A series of highly efficient semiconductor nanocrystal (NC) photocatalysts have been synthesized by growing wurtzite‐ZnO tetrahedrons around pre‐formed CdS, CdSe, and CdTe quantum dots (QDs). The resulting contact between two small but high‐quality crystals creates novel CdX/ZnO heterostructured semiconductor nanocrystals (HSNCs) with extensive type‐II nanojunctions that exhibit more efficient photocatalytic decomposition of aqueous organic molecules under UV irradiation. Catalytic testing and characterization indicate that catalytic activity increases as a result of a combination of both the intrinsic chemistry of the chalcogenide anions and the heterojunction structure. Atomic probe tomography (APT) is employed for the first time to probe the spatial characteristics of the nanojunction between cadmium chalcogenide and ZnO crystalline phases, which reveals various degrees of ion exchange between the two crystals to relax large lattice mismatches. In the most extreme case, total encapsulation of CdTe by ZnO as a result of interfacial alloying is observed, with the expected advantage of facilitating hole transport for enhanced exciton separation during catalysis.