Search

Self-assembly of noble metal nanobuilding blocks (NBBs) to hierarchical self-supported porous monoliths provides a great potential for achieving their wonderful properties along with practical applications. However, the self-assembly procedure for this kind of material reported in template and sol–gel approach is limited to specific conditions, and little interest was paid to the role of ligands in the self-assembly process to grasp the control of the structure and properties. Herein, two ligands (L1 and L2) containing thiol and glutamic acid moiety were synthesized and grafted to noble metallic nanowires and nanospheres. It had been shown that these kind of functional NBBs formed supramolecular gels in various solvents. Interestingly, these gels displayed stimulus-responsibility that has remained unreported with noble metal gels so far. In particular, the gels formed by Pt nanowires capped with L2 (PtNW-L2) demonstrated both thermo and shearing reversible gelation. Furthermore, aerogels can easily be pre...

Additional file 3: Table S2. Primer sequences used for donor construction and the detection of hDHFR gene identification.

Additional file 4: Table S3. Primer sequences used for Southern blot.

Additional file 8: Table S7. Gene expression of five differentially expressed genes at six time points.

Additional file 5: Table S4. Overview of the RNA-Seq data.

Additional file 2: Table S1. Primer sequences used for sgRNA synthesis.

Additional file 6: Table S5. The annotation of novel transcripts/genes.

TiO2 monoliths with hierarchical pores and three-dimensional (3-D) networks have attracted much interest due to their potential applications in photocatalysis, photovoltaic and electrical energy storage, etc. However, their present preparation procedures are complex and expensive. Herein, we report a novel, simple, scalable and low-cost strategy based on the self-assembly of a ligand attached to TiO2 nanoparticles (NPs) to prepare crystal TiO2 foam with micron channels and mesopores in its 3-D skeleton, which has been fabricated via centrifugation and subsequent freeze-drying of suspensions of TiO2 particles in benzene. Furthermore, FT-IR and SEM measurements demonstrated that the 3-D continuous skeleton and channels are formed in a synergistic way, which were facilitated by hydrogen bonding between ligands, and the size of these can be regulated by varying the centrifugal speed. The produced TiO2 foam acts as a good photocatalyst for the degradation of formaldehyde due to its good mass transport through the micron channels. This work provides a novel strategy for the synthesis of the hierarchical porous crystal TiO2 foam by ligand self-assembly and it would be widely used in preparing other crystal porous functional materials.

Hydrogen is a promising energy carrier and key agent for many industrial chemical processes1. One method for generating hydrogen sustainably is via the hydrogen evolution reaction (HER), in which electrochemical reduction of protons is mediated by an appropriate catalyst-traditionally, an expensive platinum-group metal. Scalable production requires catalyst alternatives that can lower materials or processing costs while retaining the highest possible activity. Strategies have included dilute alloying of Pt2 or employing less expensive transition metal alloys, compounds or heterostructures (e.g., NiMo, metal phosphides, pyrite sulfides, encapsulated metal nanoparticles)3-5. Recently, low-cost, layered transition-metal dichalcogenides (MX2)6 based on molybdenum and tungsten have attracted substantial interest as alternative HER catalysts7-11. These materials have high intrinsic per-site HER activity; however, a significant challenge is the limited density of active sites, which are concentrated at the layer edges.8,10,11. Here we use theory to unravel electronic factors underlying catalytic activity on MX2 surfaces, and leverage the understanding to report group-5 MX2 (H-TaS2 and H-NbS2) electrocatalysts whose performance instead derives from highly active basal-plane sites. Beyond excellent catalytic activity, they are found to exhibit an unusual ability to optimize their morphology for enhanced charge transfer and accessibility of active sites as the HER proceeds. This leads to long cycle life and practical advantages for scalable processing. The resulting performance is comparable to Pt and exceeds all reported MX2 candidates.

Porous materials are commonly applied in sound absorption in different places. Transmission loss, one of the vital parameters determining the performance of the material, will change when the material is compressed. Usually the compression that might affect the properties to the greatest extent are normal compression and the deformation can be simplified as 1D compression model. In order to verify the prediction, some formulas taking several parameters (porosity, tortuosity, flow resistivity and characteristic lengths) into account are applied and also the Johnson et al’s model of limp structure. Dynamic density of limp model and bulk modulus are thus obtained and to get the mathematical expression of the transmission coefficient and transmission loss, acoustic equations including Euler equation are applied to the boundary conditions between the material and the fluid (air in the experiment). The numerical predictions are later compared with experimental data collected with 4-mic 2-load measurement on Kundt standard impedance tube. Both the mathematical prediction and the experimental results shows that the transmission loss would decrease under compression and increase if the material is extended.