Frontiers of Materials Science最新文献

TiO₂ nanoparticles (NPs) in the size of ∼25 nm, namely P25, are very common material as the electron collecting layer in dye-sensitized solar cells (DSSCs). However, the light-scattering improvement of TiO₂ NP photoelectrodes is still a challenge. Here, we built TiO₂ cavities on the top of the TiO₂ NP layer by using carbonaceous microspheres as the template, forming the TiO₂ cavity/nanoparticle (C/NP) photoelectrode for the application in DSSCs. The cavity amount in the TiO₂ C/NP photoelectrode was controlled by adjusting the weight ratio of carbonaceous microspheres. SEM results confirm the successful formation of the double-layered TiO₂ C/NP electrode. J—V tests show that the optimized TiO₂ C/NP electrode prepared with 25 wt.% carbonaceous microspheres contributes to remarkable improvement of the short-circuit current density (J_sc) and the power conversion efficiency (PCE). The best photovoltaic performance solar cell with the PCE of 9.08% is achieved with the optimized TiO₂ C/NP photoelectrode, which is over 98% higher than that of the TiO₂ NP photoelectrode. Further investigations of UV-vis DRS, IPCE, OCVD, and EIS demonstrate that the competition between light scattering effect and charges recombination in this TiO₂ C/NP photoelectrode is responsible for the PCE enhancement.

ZnO-based photocatalytic materials have received widespread attention due to their usefulness than other photocatalytic materials in organic dye wastewater treatment. However, its photocatalytic efficiency and surface stability limit further applicability. This paper uses a one-step carbonization method to prepare multifunctional ZnO/carbon hybrid nanofiber mats. The carbonization creates a π-conjugated carbonaceous structure of the mats, which prolongs the electron recovery time of ZnO nanoparticles to yield improved photocatalytic efficiency. Further, the carbonization reduces the fiber diameter of the carbon hybrid nanofiber mats, which quadruples the specific surface area to yield enhanced adsorption and photocatalytic performance. At the same time, the prepared nanofiber mats can increase the evaporation rate of water under solar irradiation to a level of 1.46 kg·m⁻²·h⁻¹ with an efficiency of 91.9%. Thus, the nanofiber mats allow the facile incorporation of photocatalysts to clean contaminated water through adsorption, photodegradation, and interfacial heat-assisted distillation mechanisms.

In recent years, superhydrophobic coatings have received extensive attention due to their functions of waterproof, antifouling, self-cleaning, etc. However, wide applications of superhydrophobic coatings are still affected by their disadvantages of complex preparation, low mechanical properties, and poor ultraviolet (UV) resistance. In this study, cellulose nanocrystal containing a small amount of lignin (L-CNC)/SiO₂ composite particles were used as the main material, polydimethylsiloxane (PDMS) as the adhesive and perfluorooctyltrichlorosilane (FOTS) as the modifier to prepare superhydrophobic coatings by a one-step spray method. The resulted coating showed excellent superhydrophobicity (water contact angle (WCA) of 161° and slide angle (SA) of 7°) and high abrasion resistance (capable of withstanding 50 abrasion cycles under the load of 50 g). Moreover, it still maintained good superhydrophobicity after 5 h of exposure to the UV light (1000 W), displaying its good UV resistance. This study provides theoretical and technical reference for the simple preparation of organic-inorganic composite superhydrophobic coatings with high abrasion resistance and good UV resistance, which is beneficial to improving the practicability and broadening the application scope of superhydrophobic coatings.

Efficient chemical warfare agents (CWAs) detection is required to protect people from the CWAs in war and terrorism. In this work, a Pd-doped SnO₂ nanoparticles-based gas sensor was developed to detect a nerve agent simulant named methyl salicylate. The sensing measurements of methyl salicylate under different Pd doping amounts found that the 0.5 at.% Pd-doped SnO₂ exhibited a significant improvement in the detection of methyl salicylate at the ppb (1 ppb = 10⁻⁹) level, and the response value to 160 ppb methyl salicylate is 0.72 at 250 °C. Compared with the pure SnO₂, the response value is increased by 4.5 times, which could be attributed to the influence of the noble metal Pd on the oxygen state and its catalytic effect. In addition, the 0.5 at.% Pd-doped SnO₂ sensor still has an obvious response to 16 ppb methyl salicylate with a response value of 0.13, indicating the lower detection limit of the sensor.

The large voltage hysteresis of the NiO anode, which owes much to the intermediate product Li₂NiO₂, is one of the main obstacles to its practical application in lithium-ion batteries. In this work, we show that the incorporation of Fe- and N-ions in the NiO lattice can suppress the formation of intermediate product Li₂NiO₂ and thus greatly reduces the voltage hysteresis of the NiO anode from ∼1.2 to ∼0.9 V. In comparison with the pure NiO electrode, the Ni_0.5Fe_0.5O_1−xN_x anode exhibits significantly enhanced reversible specific capacity (959 mAh·g⁻¹ at 0.3 A·g⁻¹), cycling stability (capacity retention of 96.1% at 100th cycle relative to the second cycle) and rate capability (442 at 10 A·g⁻¹). These results provide a practical method to enhance the lithium storage performance of the NiO anode and more importantly a new solution to the large voltage hysteresis of conversion-type anodes.

As a kind of essential hydrated salt phase change energy storage materials, mirabilite with high energy storage density and mild phase-transition temperature has excellent application potential in the problems of solar time and space mismatch. However, there are some disadvantages such as supercooling, substantial phase stratification and leakage problem, limiting its further applications. In this work, for the preparation of shaped mirabilite phase change materials (MPCMs), graphene (GO), sodium carboxymethyl cellulose (CMC), and carbon nanofibers (CNFs) were used as starting materials to prepare lightweight CMC/rGO/CNFs carbon aerogel (CGCA) as support with stable shape, high specific surface area, and well-arranged hierarchically porous structure. The results show that CGCA has regular layered plentiful pores and stable foam structure, and the pore and sheet interspersed structure in CGCA stabilizes PCMs via capillary force and surface tension. The hydrophilic aerogels supported MPCMs decrease mirabilite leaking and reduce supercooling to around 0.7–1 °C. The latent heats of melting and crystallization of CGCA-supported mirabilite phase change materials (CGCA-PCMs) are 157.1 and 114.8 J·g⁻¹, respectively. Furthermore, after 1500 solid—liquid cycles, there is no leakage, and the retention rate of crystallization latent heat is 45.32%, exhibiting remarkable thermal cycling stability.

As an excellent room temperature sensing material, polyaniline (PANI) needs to be further investigated in the field of high sensitivity and sustainable gas sensors due to its long recovery time and difficulty to complete recovery. The ZnO/PANI film with p–n heterogeneous energy levels have successfully prepared by spraying ZnO nanorod synthesized by hydrothermal method on the PANI film rapidly synthesized at the gas—liquid interface. The presence of p–n heterogeneous energy levels enables the ZnO/PANI film to detect 0.1–100 ppm (1 ppm = 10⁻⁶) NH₃ at room temperature with the response value to 100 ppm NH₃ doubled (12.96) and the recovery time shortened to 1/5 (31.2 s). The ability of high response and fast recovery makes the ZnO/PANI film to be able to detect NH₃ at room temperature continuously. It provides a new idea for PANI to prepare sustainable room temperature sensor and promotes the development of room temperature sensor in public safety.

Anodic aluminum oxide (AAO) with independently controlled period, porosity, and height is used as the model surface to study the single structural parameter effect on breast cancer cell behaviors, including cell polarity and cell viability. It is found that the quantity of multipolar cells and cell viability increases as the nanodent period increases from 100 to 300 nm, while the number of bipolar cells has almost no change until there is a dramatic decrease as the period increases to 300 nm. After anodizing nanodents into nanopores, the numbers of both bipolar cells and the cell viability increase significantly with the porosity increase. However, as the porosity further increases and the nanopore changes into a nanocone pillar, most of the cells become nonpolar spheres and the cell viability decreases. Increasing the height of the nanocone pillar has little effect on the cell polarity; the cell viability increases slightly with the increase of the nanocone pillar height. These results reveal the influence of individual nanostructure parameters on the cell behavior, especially the cell polarity and the cell viability, which can help to design the surface to make the cell grow as desired.