Three-dimensionally (3D) hierarchical micro/nano oriented arrays constructed from nanometer-sized building blocks represent an important group of materials and have received enormous attention for a series of applications because they can offer both the advantages of nanosized building blocks and micro- or submicrometer-sized ordered arrays. In this work, 3D flower-like superhydrophilic CuO micro/nanostructures decorated by Ag nanoparticles were synthesized via an amino acid-assisted biomimetic hydrothermal method. Experiments reveal that the product demonstrates excellent sunlight self-cleaning performance in terms of wettability (without the help of high-free-energy compounds and in the absence of UV irradiation) and enhanced photocatalytic activities, which portends a bright future for this material as self-cleaning photovoltaic coatings. It is also a good example for the organic combination of green chemistry and functional materials.

Ag/ZnO metal–semiconductor nanocomposites with hierarchical micro/nanostructure have been prepared by the hydrothermal synthesis in the presence of bovine serum albumin (BSA). The results suggest that this biomolecule-assisted hydrothermal method is an efficient route for the fabrication of Ag/ZnO nanocomposites by using BSA both a shape controller and a reducing agent of Ag+ ions. Moreover, Ag nanoparticles on the ZnO act as electron sinks, improving the separation of photogenerated electrons and holes, increasing the surface hydroxyl contents of ZnO, facilitating trapping the photoinduced electrons and holes to form more active hydroxyl radicals, and thus, enhancing the photocatalytic efficiency of ZnO. This is a good example for the organic combination of green chemistry and functional materials.Graphical AbstractA green strategy is report to construct Ag/ZnO metal–semiconductor nanocomposites with hierarchical micro/nanostructure and enhanced photocatalytic activity.Research highlights► Hierarchical micro/nanostructured Ag/ZnO nanocomposites have been prepared via a green route. ► Ag nanoparticles improve the separation of photogenerated electrons and holes. ► This facilitates trapping the photoinduced electrons and holes to form more hydroxyl radicals. Therefore, it enhances the photocatalytic efficiency of ZnO.

In the past few years, the study of superhydrophilic surfaces has attracted considerable attention, due to their great potential in not only fundamental research but also practical applications. However, the bottlenecks in this field are (1) the use of UV irradiation, (2) the chemical modification by high-free-energy materials, and (3) the unavailability of useful superhydrophilic surfaces throughout the range of pH values from 0 through 14. In this article, we describe a method for inducing rough features on carbon surfaces using plasma technique to acquire superhydrophilic character. More interestingly and importantly, the as-prepared films are superhydrophilic for not only pure water but also corrosive liquids, such as acidic and basic solutions. This is the first example of superhydrophilicity over the whole range of pH values without the presence of high-free-energy compounds and in the absence of UV irradiation and might open up new perspectives in preparing novel nanoscale interfacial materials. The method of surface design described here does not require the use of masks or lithography, can be applied to very large surfaces in very short time, and herein offers an inexpensive and rapid method for improving the wettability of materials.

Three-dimensionally (3D) hierarchical micro/nano oriented arrays constructed from nanometer-sized building blocks represent an important group of materials and have received enormous attention for a series of applications because they can offer both the advantages of nanosized building blocks and micro- or submicrometer-sized ordered arrays. In this work, 3D flower-like superhydrophilic CuO micro/nanostructures decorated by Ag nanoparticles were synthesized via an amino acid-assisted biomimetic hydrothermal method. Experiments reveal that the product demonstrates excellent sunlight self-cleaning performance in terms of wettability (without the help of high-free-energy compounds and in the absence of UV irradiation) and enhanced photocatalytic activities, which portends a bright future for this material as self-cleaning photovoltaic coatings. It is also a good example for the organic combination of green chemistry and functional materials.