Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

To solve the problem of the global energy shortage and the pollution of the environment, in recent years, semiconductor photocatalytic technology that converts solar energy into chemical fuel has been widely studied. Regarding semiconductor-based photocatalysts, CdS has attracted extensive attention due to its relatively narrow bandgap for visible-light response and sufficiently negative potential of the conduction band edge for the reduction of protons. Studies have shown that CdS-based photocatalysts possess excellent photocatalytic performance in terms of solar-fuel generation and environmental purification. This critical review presents the recent advances and progress in the design and synthesis of various CdS and CdS-based photocatalysts. The basic physical and chemical properties of CdS and the related growth mechanism have been briefly summarized. Moreover, the applications of CdS-based photocatalysts have been discussed such as in photocatalytic hydrogen production, reduction of CO2 to hydrocarbon fuels and degradation of pollutants. Finally, a brief perspective on the challenges and future directions for the development of CdS and CdS-based photocatalysts are also presented.

CdS-Based photocatalysts

Iron oxide nanoparticles: Diagnostic, therapeutic and theranostic applications.

Catalysis is at the core of almost every established and emerging chemical process and also plays a central role in the quest for novel technologies for the sustainable production and conversion of energy. Particularly since the early 2000s, a great surge of interest exists in the design and application of micro- and nanometer-sized materials with hollow interiors as solid catalysts. This review provides an updated and critical survey of the ever-expanding material architectures and applications of hollow structures in all branches of catalysis, including bio-, electro-, and photocatalysis. First, the main synthesis strategies toward hollow materials are succinctly summarized, with emphasis on the (regioselective) incorporation of various types of catalytic functionalities within their different subunits. The principles underlying the scientific and technological interest in hollow materials as solid catalysts, or catalyst carriers, are then comprehensively reviewed. Aspects covered include the stabilizat...

Hollow Nano- and Microstructures as Catalysts

Seed-mediated growth is a powerful and versatile approach for the synthesis of colloidal metal nanocrystals. The vast allure of this approach mainly stems from the staggering degree of control one can achieve over the size, shape, composition, and structure of nanocrystals. These parameters not only control the properties of nanocrystals but also determine their relevance to, and performance in, various applications. The ingenuity and artistry inherent to seed-mediated growth offer extensive promise, enhancing a number of existing applications and opening the door to new developments. This Review demonstrates how the diversity of metal nanocrystals can be expanded with endless opportunities by using seeds with well-defined and controllable internal structures in conjunction with a proper combination of capping agent and reduction kinetics. New capabilities and future directions are also highlighted.

Seed-Mediated Growth of Colloidal Metal Nanocrystals.

In2O3-x(OH)y/Bi2MoO6 S-scheme heterojunction for enhanced photocatalytic performance

The development of photocatalysts with superior photoactivity and stability for the degradation of organic dyes is very important for environmental remediation. In this study, we have presented a multidimensional (1D and 2D) structured CdS/ZnIn2S4/RGO photocatalyst with superior photocatalytic performance. The CdS/ZnIn2S4 helical dimensional heterostructures (DHS) were prepared via a facile solvothermal synthesis method to facilitate the epitaxial growth of 2D ZnIn2S4 nanosheets on 1D CdS nanowires. Ultrathin 2D ZnIn2S4 nanosheets have grown uniformly and perpendicular to the surface of 1D CdS nanowires. The as-obtained 1D/2D CdS/ZnIn2S4 helical DHS show good photocatalytic properties for malachite green (MG). Subsequently, 2D reduced graphene oxide (RGO) was introduced into the 1D/2D CdS/ZnIn2S4 helical DHS as a co-catalyst. The photoactivity and stability of the CdS/ZnIn2S4/RGO composites are significantly improved after 6 cycles. The enhanced photoactivity can be attributed to the high surface area of RGO, the improved adsorption of organic dyes and the efficient spatial separation of photo-induced charge carriers. The transfer of photo-generated electrons from the interface of CdS and ZnIn2S4 to RGO also restricted the photocorrosion of metal sulfide, suggesting an improved stability of the reused CdS/ZnIn2S4/RGO composited photocatalyst.

Dimensional heterostructures of 1D CdS/2D ZnIn2S4 composited with 2D graphene: designed synthesis and superior photocatalytic performance.

Efficiently reclaiming the utilization of solar light in the photocatalysis system remains very challenging. Integrating full advantage of upconversion material, plasmonic metal and narrow bandgap semiconductor, β-NaYF4:18%Yb3+, 2%Tm3+@SnO2@Ag nanoparticles (denoted as NaYF4@SnO2@Ag NPs) are designed and successfully synthesized as wide-spectral (UV-Vis-NIR) responsive upconversion and plasmonic enhanced photocatalyst. The as-obtained NaYF4@SnO2@Ag NPs present broadband optical absorption dimension, excellent photocatalytic efficiency and good stability for the degradation of organic dyes. The enhanced photocatalytic performance of NaYF4@SnO2@Ag NPs can be attributed to the synergistic effects of the components composed in this core/shell architecture that result in higher photocarriers yield and favor the efficient transfer of photocarriers and energy. This work will give insight guidance of fabricating efficient, multi-component upconversion catalysts, and propose the potential in the field of high-effi...

An efficient UV-Vis-NIR responsive upconversion and plasmonic enhanced photocatalyst based on lanthanide-doped NaYF4/SnO2/Ag

We produce the p-n heterostructure of BiOBr/BiPO4 sheets with retained two-dimensional (2D) morphology through a simple solvothermal process. Comparatively, the BiOBr/BiPO4 sheets present enhanced photocatalytic performance of formaldehyde oxidation due to effective separation and migration of the photoinduced electron–hole pairs. Notably, the increasing number of grown BiPO4 particles on the surface of BiOBr sheets without isolated homogeneous BiPO4 particles are significant factors in the promotion of photocatalytic performance. Hence, the BiOBr/BiPO4 composite sheets with loading of 30% BiPO4 exhibit superior photocatalytic performance. This outstanding performance suggests that the p-n heterostructure of BiOBr/BiPO4 sheets has potential in purification of gaseous pollutants.

Efficient Visible Light Formaldehyde Oxidation with 2D p-n Heterostructure of BiOBr/BiPO4 Nanosheets at Room Temperature

Iron oxide nanocrystals (IONCs) with various geometric morphologies show excellent physical and chemical properties and have received extensive attention in recent years. The various shape-induced magnetic and electrochemical properties of the IONCs make them suitable for diverse applications. Understanding the correlation between the physicochemical properties and morphology of IONCs is a prerequisite for their widespread applications. Hence, this review focuses on current research progress regarding shape-controlled IONCs in different dimensions, and the corresponding shape-dependent magnetic, catalytic and gas-sensor properties are discussed. Furthermore, the general preparation methods, shape-guided growth mechanisms and energy conversion applications in photoelectrochemical water splitting, dye-sensitized solar cells (DSSCs) and lithium-ion batteries (LIBs) of these IONCs (α-Fe2O3, γ-Fe2O3, Fe3O4) are also discussed. Finally, the perspectives of IONCs in promising research directions are proposed.

Zhaohui Wu

Papers

In2O3-x(OH)y/Bi2MoO6 S-scheme heterojunction for enhanced photocatalytic performance

Dimensional heterostructures of 1D CdS/2D ZnIn2S4 composited with 2D graphene: designed synthesis and superior photocatalytic performance.

An efficient UV-Vis-NIR responsive upconversion and plasmonic enhanced photocatalyst based on lanthanide-doped NaYF4/SnO2/Ag

Efficient Visible Light Formaldehyde Oxidation with 2D p-n Heterostructure of BiOBr/BiPO4 Nanosheets at Room Temperature

Shape-controlled iron oxide nanocrystals: synthesis, magnetic properties and energy conversion applications