Serious freshwater shortage and environmental pollution boost the rapid development of solar-driven water production. Although improved evaporation rate has achieved in recent years, undesirable impurity (e.g., pollutant components) can also be inevitably evaporated and collected as impurity in produced freshwater. This work reports new ultra-light threedimensional (3D) aerogels assembled by hierarchical Al 2 O 3 /TiO 2 nanofibers and reduced graphene oxide (RGO) for exciting synchronized solar-driven evaporation and water purification. Hydrophilic Al 2 O 3 /TiO 2 fibrous channels linked up the graphene hot-spots and water body for sufficient water supply and bulk water insulation. Meanwhile, featured with thermal insulation effect, the Al 2 O 3 /TiO 2 nanofibers effectively locked the converted heat with less energy loss from sunlight. The introducing of Al 2 O 3 /TiO 2 nanofibers into RGO aerogel led to the effective interfacial evaporation for a more rapid water evaporation rate (2.19 kg • m −2 • h −1 , normalized to evaporation area including both top and side surface), which was 36% higher than that of pristine RGO aerogel. Moreover, simultaneous with the strong steam generation, Al 2 O 3 /TiO 2 nanofibers in situ removed the pollutants within steam by photodegradation, achieving polluted wastewater purification with high contaminant removal ratio of 91.3%. Our work on coupling Al 2 O 3 /TiO 2 nanofibers into photothermal aerogel provides attractive solutions for the challenges of clean water scarcity and serious environmental pollution.

Gold nanoparticles (Au NPs) have attracted remarkable research interests in heterogeneous catalysis due to their unique physical and chemical properties. However, only small-size Au NPs (<7 nm) exhibit promising catalytic activity. In this work, dumbbell-like Au NPs (D-Au NPs) with average size of 37 × 11 nm were prepared by a secondary seed-mediated growth method to serve as novel photocatalyst for ammonia borane (AB) hydrolysis in the solution with specific pH value. Our results demonstrate that ⅰ) the strengthened LSPR compensation effect could effectively remedy the loss of catalytic activity resulting from the size enlarging of D-Au NPs, proven by that the heating power of a single Au nanoparticle (Ps) and turnover frequency of AB molecules within 10 minutes of D-Au NPs are 52.5 and 3.89 times higher than that of spherical Au NPs; ⅱ) the extinction coefficient and Ps of D-Au NPs are almost 2.72 and 2.42 times as high as that of rod-like Au NPs, demonstrating the promoting structure-property relationship of dumbbell-like structure.; ⅲ) when the pH value of AB solution was lower than 6.0, the hydrolysis rate was highly promoted, indicating that H+ ions play an active role in the hydrolysis process. This work greatly extends the application of noble metals and provides a new insight into AB hydrolysis.

The incorporation of nano-reinforcements is believed to be a promising method to create high performance nanocomposites, which are largely dependent on the interfacial connections. In this work, the newly emerging two-dimensional (2D) material, 2Dsilica is intentionally intercalated into the interlayer defective sites of calcium silicate hydrate (C-S-H), which is the primary hydration product of ordinary portland cements. The reactive molecular simulation results indicate the nano-reinforcement can strongly interact with the inorganic matrix to form a high-ductility nanocomposite. The uniaxial tensile loading tests show the plastic stage of the C-S-H is considerably enhanced due to the intercalation of 2D-silica, which removes the intrinsic brittleness of cementbased materials at the nano-scale. It is observed that the dangling atoms at the edge of 2D-silica can react with non-bridging oxygen atoms of C-S-H, forming Si-O-Si bonds at interfaces. Those covalent bonds transform Q 1 and Q 2 in the C-S-H into high connectivity Q 3 and Q 4 species, which increases the integrity of the matrix and its resistance to crack propagation. During the tensile process, the elongation and breakage of those high-strength covalent bonds needs higher tensile stress and consumes higher energy, which leads to a strong plasticity and higher toughness. This work may shed new lights on the interaction mechanisms between 2D-materials and inorganic hosts, and provide solutions to modifying the brittleness of concrete.

The major challenge in improving the photoelectrochemical performance of Fe2O3 lies on increasing the photon absorption capability and the charge transfer efficiency. In this work, we facilely maneuvered the morphology of Fe2O3 nanomaterials by a combination of electrospinning and hydrothermal approach. Through controlling the type, the concentration of inorganic species, and the consequent ionic strength of hydrothermal solution, the hematite with four different nanostructures (i.e., nanoflowers, nanocubes, irregular nanoparticles, and flat nanoflakes) were engineered. The narrow bandgap of 1.85 eV and the unique structure of flower-Fe2O3 allowed an enhanced photon absorption and thus a small charge transfer resistance (R ct) of 32.2 Ω. After coupling with RGO sheets, Fe2O3 nanostructures experienced decreased size and enriched defects, facilitating enhanced photoelectrochemical performance. Taking the flower-Fe2O3/RGO as an example, the R ct declined to 21.8 Ω and the steady state photocurrent density increased up to 220.2 μA/cm2 (3. folds of that of pristine flower-Fe2O3). Moreover, this improvement should also be ascribed to RGO sheets that act as a bridge to enhance the charge transfer efficiency and further retard the undesirable recombination of electrons and holes. The present work will deepen the understanding of precise control over the morphology of inorganic nanocrystals as well as their structure-related performance.

High density phase change memory array requires both minimized critical dimension (CD) and maximized process window for the phase change material layer. High in-wafer uniformity of the nanoscale patterning of chalcogenides material is challenging given the optical proximity effect (OPE) in the lithography process and the micro-loading effect in the etching process. In this study, we demonstrate an approach to fabricate high density phase change material arrays with half-pitch down to around 70 nm by the co-optimization of lithography and plasma etching process. The focused-energy matrix was performed to improve the pattern process window of phase change material on a 12-inch wafer. A variety of patternings from an isolated line to a dense pitch line were investigated using immersion lithography system. The collapse of the edge line is observed due to the OPE induced shrinkage in linewidth, which is deteriorative as the patterning density increases. The sub-resolution assist feature (SRAF) was placed to increase the width of the lines at both edges of each patterning by taking advantage of the optical interference between the main features and the assistant features. The survival of the line at the edges is confirmed with around a 70 nm half-pitch feature in various arrays. A uniform etching profile across the pitch line pattern of phase change material was demonstrated in which the micro-loading effect and the plasma etching damage were significantly suppressed by co-optimizing the etching parameters. The results pave the way to achieve high density device arrays with improved uniformity and reliability for mass storage applications.