Modularization of Regional Electronic Structure over Defect-Rich CeO2 Rods for Enhancing Photogenerated Charge Transfer and CO2 Activation.

Oxygen vacancy (OV) engineering has been widely applied in different types of metal oxide-based photocatalytic reactions. Our study has shown that the redistributed OVs resulting from voids in CeO2 rods lead to significant differences in the band structure in space. The flat energy band within the highly crystallized bulk region hinders the recombination of photogenerated carrier pairs during the transfer process. The downward curved energy band in the surface region enhances the activation of the absorbents. Therefore, the localization of the band structure through crystal structure regionalization renders V-CeO2 capable of achieving efficient utilization of photogenerated carriers. Practically, the V-CeO2 rod shows a remarkable turnover number of 190.58 µmol g-1 h-1 in CO2 photoreduction, which is ∼9.4 times higher than that of D-CeO2 (20.46 µmol g-1 h-1). The designed modularization structure in our work is expected to provide important inspiration and guidance in coordinating the kinetic behavior of carriers in OV defect-rich photocatalysts.

Achieving Molecular-Level Selective Detection of Volatile Organic Compounds through a Strong Coupling Effect of Ultrathin Nanosheets and Au Nanoparticles.

The high density of surface active sites, high efficiency of interfacial carrier transport, and molecular diffusion path determine the efficiency of the electrochemical sensors. The ultrathin structures have atomic-level thickness, carrier migration and heat diffusion are limited in the two-dimensional plane, resulting in excellent conductivity and high carrier concentration. A one-step chemical method is applied to synthesize defect-rich Au-SnO2 in an ultrathin nanosheet form (thickness of 2-3 nm). The strong interaction between Au and SnO2 via the Au-O-Sn bonding and the catalytic effect of Au can prolong the service life via decreasing the optimal operating temperature (55 °C) and promote the Au-SnO2 sensor to exclusively detect formaldehyde at the ppb level (300 ppb). The experimental findings along with theoretical study reveal that Au nanoparticles have a different effect on the competitive adsorption and chemical reaction over the surface of the Au-SnO2 with formaldehyde and other interfering VOC gases, such as methanol, ethanol, and acetone. This study provides mechanistic insights into the correlation between operating temperature and the performance of the Au-SnO2 chemiresistive sensor. This work allows the development of highly efficient and stable electrochemical sensors to detect VOC gases at room temperature in the future.

Strength and Deformation Characteristics of Fiber and Cement-Modified Waste Slurry.

Using fiber and cement to modify waste slurry and apply it to roads is an effective way to recycle waste slurry. A new type of road material, fiber-cement-modified waste slurry (FRCS), was prepared in this study. The static and dynamic characteristics of the cement soil were studied using an unconfined compressive strength test and dynamic triaxial test. The results show that the optimum fiber content of FRCS is 0.75%. In the unconfined compressive strength test, under this fiber content, the unconfined compressive strength (UCS) of the FRCS is the largest, and the elastic modulus and modulus strength ratio are both the smallest, indicating that the tensile properties of the cement slurry have been enhanced. In the dynamic triaxial test, the hysteretic curve of the FRCS tends to be stable with the increase in the number of cycles, the dynamic elastic modulus of the FRCS decreases first and then increases with the increase in the dosage, while the damping ratio becomes stable after a rapid decline, and the fiber incorporation increases the cumulative strain of the soil-cement under low-stress cycles, indicating that the ductility of the FRCS is improved. In addition, a cumulative strain prediction model of the FRCS is established in this paper, which can provide a reference for the resource application of waste slurry in road engineering.

A concise synthesis of thioaurones via NBS-induced cyclization of MOM-protected 2'-mercaptochalcones.

A mild and efficient approach for the synthesis of thioaurones via NBS-induced cyclization of methoxymethyl-protected mercapto-chalcones has been developed. This simple method is highly functional group tolerant and provides straightforward access to thioaurones in good to high yields.

Effect of Structural Design on the Pore Structure, Water Resistance, and Mechanical Properties of Engineered Wood/Bamboo Laminated Composites.

An important principle in rational manufacturing design is matching the properties of composites to their intended uses. Herein, six laminated composites (LCs) were manufactured using fibrous moso bamboo and poplar veneer units, and their pore structure, water resistance, and mechanical properties were evaluated. The LC density (640-1290 kg/m3) increased significantly with increasing bamboo veneer unit content. The LC surface texture and roughness depended on the density and type of surface layer. With increasing LC density, the water absorption rate (WAR), width swelling rate (WSR), and thickness swelling rate (TSR) decreased exponentially and the mechanical properties increased linearly. This behavior was closely related to the changes in pore structure caused by density. Notably, the water resistance and mechanical properties of the LCs with densities higher than 910 kg/m3 were superior to the highest levels specified in GB/T 20241-2006 for ''laminated veneer lumber'' and GB/T 30364-2013 for "bamboo scrimber flooring". Thus, these engineered materials are promising for outdoor structures and flooring.

Selective synthesis of 3-formylbenzofuran and 3-acylbenzofuran using a chalcone rearrangement strategy.

We developed a method for highly selective synthesis of two benzofuran isomers, by rearranging and subsequently transforming 2-hydroxychalcones. Depending on the reaction conditions, synthesis of 3-formylbenzofurans, unconventional products, and 3-acylbenzofurans was achieved through cyclized 2,3-dihydrobenzofurans obtained from the rearranged products. The facile synthesis of 3-formylbenzofurans facilitated synthesis of the natural product, puerariafuran, from the corresponding chalcone.

Physical and Mechanical Properties of Novel Multilayer Bamboo Laminated Composites Derived from Bamboo Veneer.

Compared with wood, bamboo has a special fiber gradient structure. Bamboo fibers have attracted attention as reinforced polymer composites. This study investigated the effects of lamination and fiber volume on the physical and mechanical properties of bamboo laminated composites (BLCs). Six types of BLC were derived by parallel and cross laminating bamboo veneers with high, middle, and low fiber volumes. The results indicated that the laminated structure and fiber volume significantly influenced the BLC properties. Microstructural analysis showed that parallel lamination and low fiber volume were more conducive to resin penetration and enhanced the bonding strength. Both the bending and tensile strengths of the cross lamination were lower than those of the parallel lamination. BLCs made of veneers with high and middle fiber volumes and parallel lamination had the maximum bending and tensile strengths (145.1 and 101.53 MPa, respectively). When tested for water resistance, parallel and cross lamination inhibited expansion in the thickness (TSR, 0.56-2.14%) and width (WSR, 0.07-1.61%) directions, respectively. Laminated structures and veneers with varying fiber volume contents should be chosen according to the specific application scenarios. This study provides a reference for selecting an appropriate BLC structure and fiber volume based on application.

Morphological, Chemical, and Physical-Mechanical Properties of a Clumping Bamboo (Thyrsostachys oliveri) for Construction Applications.

In view of the long-term utilization history as a building and furniture making material in southeast Asian countries, Thyrsostachys oliveri is considered to have great utilization potential. However, little is known about the quantitative morphological characteristics and comprehensive material properties of its culm. In this study, we systematically investigated the morphological characteristics, the chemical components, and the physical-mechanical properties of the three-year-old culm of T. oliveri. The morphological analysis result showed that the internode length, the diameter of internodes and the wall thickness changed with the culm height. The volume of the culm wall of a single internode increased before the 10th internode, and then it decreased to a significant level at the 20th internode. The basic chemical compositions (cellulose, hemicellulose, lignin and silicon content) of the culm wall were 346.19 mg/g, 95.32 mg/g, 33.17%, and 3.39 mg/g, respectively. These component contents were relatively stable in the bottom and middle part of the culm, but changed significantly in the upper part of the culm. The moisture content and the base density of the culm wall were 73.01% and 0.64 g/cm3, respectively. The culm wall shrinkage rate in the radial, tangential direction as well as the volumetric shrinkage reached the minimum value in the middle part of the culm. The average compressive strength, modulus of rupture and modulus of elasticity of the culm wall were 67.03 MPa, 143.74 MPa, and 7.99 GPa, respectively. These results provide valuable reference data for more rational use of this bamboo resources.

Optically Transparent Bamboo: Preparation, Properties, and Applications.

The enormous pressures of energy consumption and the severe pollution produced by non-renewable resources have prompted researchers to develop various environmentally friendly energy-saving materials. Transparent bamboo represents an emerging result of biomass material research that has been identified and studied for its many advantages, including light weight, excellent light transmittance, environmental sustainability, superior mechanical properties, and low thermal conductivity. The present review summarizes methods for preparing transparent bamboo, including delignification and resin impregnation. Next, transparent bamboo performance is quantified in terms of optical, mechanical, and thermal conductivity characteristics and compared with other conventional and emerging synthetic materials. Potential applications of transparent bamboo are then discussed using various functionalizations achieved through doping nanomaterials or modified resins to realize advanced energy-efficient building materials, decorative elements, and optoelectronic devices. Finally, challenges associated with the preparation, performance improvement, and production scaling of transparent bamboo are summarized, suggesting opportunities for the future development of this novel, bio-based, and advanced material.

Photodegradation and Photostability of Bamboo: Recent Advances.

Bamboo and its products are widely used in indoor and outdoor fields. Photodegradation occurs easily on the surface when bamboo is exposed to ultraviolet (UV) light from solar radiation. This induces surface discoloration and degrades the physical properties of bamboo, which not only negatively affects its utility and aesthetic characteristics but also restricts its application in outdoor environments. In this work, we review the mechanism of bamboo photodegradation, in which the behavior of lignin is key. The changes in bamboo's microstructure, surface color, and chemical composition during photodegradation are described in detail. Methods for enhancing its photostability, including the application of transparent coatings containing UV absorbers and hindered amine light stabilizer compounds on bamboo surfaces, are then systematically summarized, and potential approaches to combat the photodegradation of bamboo surfaces are discussed. On the basis of the recent advances of photodegradation and photostability of bamboo, this review provides new insights into the scientific application and protection of bamboo in the outdoor field.

Changes in Chemical and Thermal Properties of Bamboo after Delignification Treatment.

Bamboo delignification is a common method for studying its functional value-added applications. In this study, bamboo samples were delignified by treatment with sodium chlorite. The effects of this treatment on the bamboo's microstructure, surface chemical composition, and pyrolysis behaviour were evaluated. Field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were conducted to evaluate these parameters. The FTIR results demonstrated that the lignin peak decreased or disappeared, and some hemicellulose peaks decreased, indicating that sodium chlorite treatment effectively removed lignin and partly decomposed hemicellulose, although cellulose was less affected. The XPS results showed that, after treatment, the oxygen-to-carbon atomic ratio of delignified bamboo increased from 0.34 to 0.45, indicating a lack of lignin. XRD revealed increased crystallinity in delignified bamboo. Further pyrolysis analysis of treated and untreated bamboo showed that, although the pyrolysis stage of the delignified bamboo did not change, the maximum thermal degradation rate (Rmax) and its corresponding temperature (from 353.78 to 315.62 °C) decreased significantly, indicating that the pyrolysis intensity of the bamboo was weakened after delignification. Overall, this study showed that delignified bamboo develops loose surfaces, increased pores, and noticeable fibres, indicating that alkali-treated bamboo has promising application potential due to its novel and specific functionalities.

TiO2 with exposed (001) facets/Bi4O5Br2 nanosheets heterojunction with enhanced photocatalytic for NO removal.

A TiO2 with exposed (001) facets/Bi4O5Br2 nanosheets heterojunction (TNS/BOB) was fabricated via a hydrothermal and electrostatic self-assembly method. The photocatalytic activity for NO removal was evaluated under simulated solar light irradiation. Through optimizing the content of TNS nanosheets, the photo-oxidative NO removal rate of 15% TNS/BOB was increased by up to 54.3%. This value is much higher than that of the individual components TNS (31.1%) and BOB (37.7%). Through capturing experiments and electron spin resonance (ESR) measurements, the main active species in the photocatalytic process were identified as ·[Formula: see text] and ·OH. Discrete Fourier transform computation results and ESR tests revealed that the photo-induced electrons in TNS should recombine with the holes in BOB, leading to effectively promoted charge separation at the TNS/BOB interface through the Z-type charge transfer. This work showed that with appropriate facet control and heterojunction design TiO2 can be used as an effective visible-light photocatalyst material.

Novel Au/La-Bi5O7I Microspheres with Efficient Visible-Light Photocatalytic Activity for NO Removal: Synergistic Effect of Au Nanoparticles, La Doping, and Oxygen Vacancy.

Sphere-like Bi5O7I (BOI) doped with La (L-BOI) samples were prepared by a solvothermal method followed by calcination at 450 °C for 2 h. Au nanoparticles were loaded on 6% La-doped Bi5O7I (2%A-6%L-BOI) microspheres by a room-temperature chemical reduction method. The UV-vis absorption spectra show that the L-BOI and 2%A-6%L-BOI samples have a strong visible-light absorption in comparison with the pure BOI. The electron paramagnetic resonance results indicate that the number of oxygen vacancies in L-BOI samples is increased with an increasing amount of the La dopant. The band structure of the prepared photocatalysts is investigated by confirming the positions of the valence band (VB) measured by XPS-VB and the Fermi level computed by density functional theory, respectively. NO is selected as a target gaseous pollutant to confirm the influence of La doping and the plasmonic effect of Au nanoparticles on the photocatalytic activity of BOI microspheres. The 2%A-6%L-BOI sample exhibits an enhanced photocatalytic performance compared to BOI, L-BOI, and A-BOI photocatalysts under visible-light irradiation. Interestingly, the 2%A-6%L-BOI sample also can reduce the amount of intermediate NO2 during the NO removal process. The enhanced photocatalytic efficiency of the 2%A-6%L-BOI photocatalyst is profited from the synergy of La-ion doping, oxygen vacancy, and the surface plasmon resonance effect of Au nanoparticles. Based on the results of trapping experiments and electron spin resonance spectroscopy tests, h+, e-, and •O2- were involved in the NO oxidative removal.