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•New crystalline/amorphous (c/a) TiO2 hybrid films are prepared via a facile method.•Optimal crystalline/amorphous interface can be realized in c/a-TiO2 hybrid.•The prepared porous ...c/a-TiO2 hybrid shows superior electrochromic performance.
Porous crystalline/amorphous TiO2 (c/a-TiO2) hybrid films have been successfully grown on FTO substrates via a solvothermal reaction followed by a simple air annealing treatment. By adjusting reaction temperature, the porous structure and the proportion of amorphous TiO2 phase can be feasibly modulated. The in-situ transformation of crystalline TiO2 from amorphous phase could ensure the optimal crystalline/amorphous interface contact. The obtained c/a-TiO2 hybrid films shows excellent electrochromic properties which can switch between green color and transparent state with large optical contrast (59.3%) at 700 nm, high coloration efficiency (24.3 cm2 C−1) and short switching time (bleaching time of 2.0 s and coloration time of 12.1 s). Due to the desired porous structure for short Li+ ions diffusion paths and crystalline/amorphous interface enables low energy barrier and fast ion migration during the insertion/extraction of Li+ ions, the c/a-TiO2 hybrid film not only exhibits lower threshold voltage (+0.2 ∼ −1.5 V vs Ag/AgCl) and faster response than single crystalline anatase TiO2 (c-TiO2) counterpart, but also owns higher coloration efficiency and better durability than single amorphous TiO2 (a-TiO2). Compared to the commonly blue color of c-TiO2, the success to gain green color by using the prepared c/a-TiO2 hybrid film makes it very attractive for constructing electrochromic devices. Our study here also offers an alternative way of designing TiO2-based nanostructures for high-efficiency electrochromic applications.
The sensitive and rapid detection of nitroaromatic explosives typically requires sophisticated sensor materials. We demonstrate here how a simple dip-coating process of a mixture of polystyrene and ...the fluorophore pyrene onto a glass slide generates a self-assembled fluorescent nanostructured film expressing regular breath-figure nanopores. Morphology investigation reveals that the fluorescent polymer films consist of a high-density, three-dimensional nanoporous array of holes, allowing the fluorescence of this material to be rapidly and selectively quenched by nitroaromatic vapors. The morphology of the polymer was controlled by variation of the dip-coating parameters and the ratio of polystyrene to pyrene. This ratio also controls the fluorescence quenching efficiency of the material. We demonstrate the possible molecular origins of this through structural XRD studies as well as investigations of the electronic structure (optical properties, band gap and conduction band determinations) of the polymer film. Our results identify a novel high performance form of an otherwise known explosive-sensing material. Most importantly, the findings point toward a general method for the facile realization of well-defined three-dimensional high surface sensor materials with optimized electronic properties.
The detection of explosives is one of the current pressing concerns in global security. In the past few decades, a large number of emissive sensing materials have been developed for the detection of ...explosives in vapor, solution, and solid states through fluorescence methods. In recent years, great efforts have been devoted to develop new fluorescent materials with various sensing mechanisms for detecting explosives in order to achieve super-sensitivity, ultra-selectivity, as well as fast response time. This review article starts with a brief introduction on various sensing mechanisms for fluorescence based explosive detection, and then summarizes in an exhaustive and systematic way the state-of-the-art of fluorescent materials for explosive detection with a focus on the research in the recent 5 years. A wide range of fluorescent materials, such as conjugated polymers, small fluorophores, supramolecular systems, bio-inspired materials and aggregation induced emission-active materials, and their sensing performance and sensing mechanism are the centerpiece of this review. Finally, conclusions and future outlook are presented and discussed.
The state-of-the-art of fluorescent materials and their sensing mechanism/properties for the detection of explosives in the recent 5 years were systematically reviewed.
Fluorescent polymeric materials such as hydrogels and particles have been attracting attention in many biomedical applications including bio-imaging, optical sensing, tissue engineering, due to their ...good biocompatibility, biodegradability, and advanced optical property. This review article aims at summarizing recent progress in fluorescent hydrogels and particles based on natural polymers or natural-synthetic hybrid polymers as the building blocks with a concentration on their bio-imaging-related applications. The challenges and future perspectives for the development of natural or natural-synthetic hybrid polymer-based fluorescent hydrogels and particles are also presented.
Catalysis as a field is classically divided into three areas: homogeneous, heterogeneous, and biological catalysis.1 For the latter two, i.e., biological catalysis and heterogeneous catalysis, their ...dissimilarity can be apparent intuitively, from the scenes of fruit fermentation in a rural winery to make wine and oil refining in a process plant to produce gasoline. In addition to the practical differences, technological terms common in both areas show divergences in meaning. Here, a highly relevant example is the term turnover number.2 It refers to the maximum number of substrate molecules converted to products per enzyme molecule per second, often written as kcat in enzyme catalysis; while the same term means the number of moles of reactants that a mole of catalyst converts before deactivation, usually abbreviated as TON in heterogeneous catalysis.
Very brief microwave heating of aniline, ethylene diamine, and phosphoric acid in water at ambient pressure generated nitrogen and phosphorus co-doped carbon dots (N,P-CDs) that exhibit bright dual ...blue (centred at 450 nm; 51% quantum yield) and green (centred at 510 nm, 38% quantum yield) fluorescence emission bands. The N,P-CDs were characterized using TEM, XRD, XPS, IR, UV-vis, and fluorescence spectroscopy, demonstrating their partially crystalline carbon, partially amorphous structures, and the incorporation of O, N, and P into the carbogenic scaffold. The N,P-CDs demonstrated excitation-dependent and nearly pH-independent emission properties. The unique dual emission properties lay the foundation for the use of N,P-CDs in ratiometric sensing applications.
Microwave-assisted synthesis of nitrogen and phosphorus co-doped carbon dots with high quantum yield and dual (blue and green) fluorescence emission.
Reduced graphene oxide (rGO) was prepared using oxalic acid in th e presence of montmorillonite (Mt) via hydrothermal treatment. The structure characterizations indicated that the porous structure of ...the obtained rGO and the residual oxygen groups were dominated by carbonyl and carboxyl groups. The mechanism analysis showed that the introduction of Mt. ensured the formation of isolated graphene oxide nanosheets free from being reduced by oxalic acid, further alleviating the irreversible restacking of rGO sheets. Electrochemical measurements demonstrated that the resultant rGO electrode offered a high specific capacitance (Cs) of 315 F/g at 1 A/g in a three-electrode configuration and the symmetric supercapacitor based on this electrode exhibited superior cycle stability with 89.7% capacitance retention after 10,000 cycles. This present work proposes a novel strategy for controlling the effects of oxalic acid on GO via employing multi-role Mt., also expands the preparation scope of graphene-based electrode materials.
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•Oxalic acid can effectively reduce graphene oxide and make pores on its surface.•Mt. performs a multifunctional effect on regulating the microstructure of graphene.•The carbonyl-rich graphene has appropriate pore diameter.•Obtained samples show superior specific capacitance retention and cyclic stability.
Bacterial infections are the cause of rhizome rot in ginger (
). Key members of the endophytic microbial community in ginger rhizomes have not been identified, and their impact on the decay of ...rhizomes during the activation of adventitious bud development has not been investigated. High-throughput, 16S rRNA amplicon sequencing and inoculation experiments were used to analyze the microbial diversity, community structure and composition, and pathogenicity of isolated bacteria. Our results indicated that the composition of the endophytic microbiota underwent a shift during the progression of rhizome rot disease.
,
, and the bacterial genera
,
,
,
,
,
, and
were relatively abundant in the bacterial community of rhizomes exhibiting bacterial decay symptoms but were also present in asymptomatic rhizomes. The presence of
and
were positively correlated (
= 0.83) at the beginning of the sampling period in the symptomatic group, while a positive correlation (
= 0.89) was only observed after 20 days in the asymptomatic group. These data indicate that the co-occurrence of
and
may be associated with the development of ginger rot. Bacterial taxa isolated from ginger rhizomes, such as
,
, and
, induced obvious rot symptoms when they were inoculated on ginger rhizomes. Notably, antibiotic-producing bacterial taxa in the
and
were also relatively abundant in rhizomes with rot and appeared to be linked to the onset of rhizome rot disease. Our results provide important information on the establishment and management of disease in ginger rhizomes.
