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In this study, we developed a multifunctional chitosan film with visible light-responsive photocatalytic properties by incorporating a novel nanofiller-a nanohybrid particle of poly(tannic acid) (PTA) and TiO2 (TP-NPs). Firstly, the hybridization of TiO2 with PTA not only improved its dispersion but also obtained TP-NPs with smaller band gaps (from 3.11 eV to 1.55 eV) and higher separation efficiency of photogenerated e--h+ (about 1.5-fold enhancement), thereby producing more reactive oxygen species and enhancing the antibacterial efficacy (compared with TiO2, the antibacterial effect of TP-NPs on Staphylococcus aureus and Escherichia coli was heightened by about 2 times under visible light for 1 h). Secondly, TP-NPs were hydrogen bonded with chitosan, strengthening its mechanical and barrier properties, while imparting exceptional antibacterial efficacy. Moreover, the multifunctional properties enabled the active film to effectively delay the quality deterioration of grapes and kiwifruit. Hence, this study presented a multifunctional active packaging film tailored for fruit preservation.

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The fabrication of solid solutions represents a compelling approach to modulating the physicochemical properties of materials. In this study, we achieved the successful synthesis of solid solutions comprising SrTiO3 and SrTaO2N (denoted as (SrTiO3)1-x-(SrTaO2N)x, 0≤x≤1) using the magnesium powder-assisted nitridation method. The absorption edge of (SrTiO3)1-x-(SrTaO2N)x is tunable from 500 to 600 nm. The conduction band minimum (CBM) of (SrTiO3)1-x-(SrTaO2N)x comprises the Ti 3d orbitals and the Ta 5d orbitals, while the valence band maximum (VBM) consists of the O 2p and N 2p orbitals. The microstructure of the (SrTiO3)1-x-(SrTaO2N)x consists of small nanoparticles, exhibiting a larger specific surface area than the parent compounds of SrTiO3 and SrTaO2N. In the photocatalytic hydrogen evolution reaction (HER) with sacrificial reagents, the activity of solid solutions is notably superior to that of nitrogen-doped SrTiO3 and SrTaO2N. This superiority is mainly attributed to its broad light absorption range and high charge separation efficiency, which indicates its potential as a promising photocatalytic material. Moreover, the magnesium powder-assisted nitridation method exhibits obvious advantages for the synthesis of oxynitrides and bears instructional significance for the synthesis of other nitrogen-containing compounds and even sulfur-containing compounds.

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Disposable bamboo chopsticks (DBCs) are difficult to recycle, which inevitably cause secondary pollution. Based on energy and environmental issues, we propose a facile strategy to fabricate floatable photocatalyst (fPC) coated onto DBCs, which can be flexibly used in water purification. The photocatalyst of titania and titanium carbide on bamboo (TiO2/TiC@b) was successfully constructed from TiC-Ti powders and DBCs using a coating technique followed heat treatment in carbon powder, and the fPC exhibited excellent photocatalytic activity under visible light irradation. The analysis results indicate that rutile TiO2 forms on TiC during heat treatment, achieving a low-density material with an average value of approximately 0.5233 g/cm3. The coatings of TiO2/TiC on the bamboo are firm and uniform, with a particle size of about 20-50 nm. XPS results show that a large amount of oxygen vacancies is generated, due to the reaction atmosphere of more carbon and less oxygen, further favoring to narrowing the band gap of TiO2. Furthermore, TiO2 formed on residual TiC would induce the formation of a heterojunction, which effectively inhibits the photogenerated electron-hole recombination via the charge transfer effect. Notably, the degradation of dye Rhodamine B (Rh.B) is 62.4% within 3 h, while a previous adsorption of 36.0% for 1 h. The excellent photocatalytic performance of TiO2/TiC@b can be attributed to the enhanced reaction at the water/air interface due to the reduced light loss in water, improved visible-light response, increased accessible area and charge transfer effect. Our findings show that the proposed strategy achieves a simple, low-cost, and mass-producible method to fabricate fPC onto the used DBCs, which is expected to applied in multiple fields, especially in waste recycling and water treatment.

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Developing narrow-band-gap ferroelectric semiconducting photocatalysts is a promising strategy for efficient photocatalytic water splitting with high energy conversion efficiency. Within this context, six ferro/nonferroelectric vertical heterostructure superlattices (VHSs) are constructed in this work by stacking ferroelectric SiS or GeS with nonferroelectric layered organic photocatalysts (C2N, g-C3N4, and melon), layer by layer. The geometry and electronic structures of these six VHSs are systematically investigated by density functional theory calculations. Consequently, four VHSs (SiS/g-C3N4, GeS/C2N, GeS/g-C3N4, and GeS/melon) are predicted to simultaneously possess several important and highly desirable features for photocatalytic water splitting, namely excellent visible-light adsorption, remarkable spontaneous polarization (0.49-0.70 C/m2), spatial charge separation, as well as suitable band-edge positions, thus serving as potential candidates for photocatalytic water splitting to produce hydrogen. This work not only provides a new strategy to use narrow-band-gap ferroelectric semiconductors for photocatalytic water splitting but also offers inspiration for developing photocatalysts with high energy conversion efficiency.

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Smart textiles demonstrating optical responses to external light stimuli hold great promise as functional materials with a wide range of applications in personalized decoration and information visualization. The incorporation of high-contrast, vivid, and real-time optical signals, such as color change or fluorescence emission, to indicate light on/off states is both crucial and challenging. In this study, we have developed a dual output photosensitive dye system possessing photochromic and photofluorescent properties, which was successfully applied to the dyeing and finishing processes of cotton fabrics. The design and fabrication of this dye system were based on the unique photoinduced proton transfer (PPT) principle exhibited by the water-soluble spiropyran (trans-MCH) molecule. The dual output response relies on the open-/closed-loop mechanism, wherein light regulates the trans-MCH molecule. Upon excitation by UV or visible light, the dye system and dyed fabrics display significant color changes and fluorescence switching in a real-time and highly reversible manner. Moreover, diverse photosensitive color systems can be tailored by direct blending with commercially available water-soluble dyes. By integrating high-contrast dual optical outputs into this scalable, versatile, and reversible dye system, we envisage the development and design of smart textiles capable of producing high-end products.

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To explore the mechanism and pathway for pollutant degradation in seawater by heterogeneous photocatalysts, the degradation of tetracycline (TC) in pure water and simulated seawater with different mesoporous TiO2 under the excitation of visible light was first investigated; then the effect of different salt ions on the photocatalytic degradation process was clarified. Combined with radical trapping experiments, electron spin resonance (ESR) spectroscopy, and intermediate product analysis, the main active species for photodegrading pollutants and the pathway of TC degradation in simulated seawater were investigated. The results showed that the photodegradation for TC in simulated seawater was significantly inhibited. Compared with the TC photodegradation in pure water, the reaction rate of the chiral mesoporous TiO2 photocatalyst for TC was reduced by approximately 70%, whereas the achiral mesoporous TiO2 photocatalyst could hardly degrade TC in seawater. Anions in simulated seawater had little effect on photodegradation, but Mg2+ and Ca2+ ions significantly inhibited the TC photodegradation process. Whether in water or simulated seawater, the active species generated by the catalyst after excitation by visible light were mainly holes, and each salt ion did not inhibit the generation of active species; thus, the degradation pathway both in simulated seawater and in water was the same. However, Mg2+ and Ca2+ would be enriched around the highly electronegative atoms in TC molecules, hindering the attack of holes to highly electronegative atoms in TC molecules, thereby inhibiting the photocatalytic degradation efficiency.

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The extraction of titanium-bearing components in the form of CaTiO3 is an efficient utilization of blast furnace slag. The photocatalytic performance of this obtained CaTiO3 (MM-CaTiO3) as a catalyst for methylene blue (MB) degradation was evaluated in this study. The analyses indicated that the MM-CaTiO3 had a completed structure with a special length-diameter ratio. Furthermore, the oxygen vacancy was easier to generate on a MM-CaTiO3(110) plane during the photocatalytic process, contributing to improving photocatalytic activity. Compared with traditional catalysts, MM-CaTiO3 has a narrower optical band gap and visible-light responsive performance. The degradation experiments further confirmed that the photocatalytic degradation efficiency of pollutants by using MM-CaTiO3 was 3.2 times that of pristine CaTiO3 in optimized conditions. Combined with molecular simulation, the degradation mechanism clarified that acridine of MB molecular was stepwise destroyed by using MM-CaTiO3 in short times, which is different from demethylation and methylenedioxy ring degradation by using TiO2. This study provided a promising routine for using solid waste to obtain catalysts with excellent photocatalytic activity and was found to be in keeping with sustainable environmental development.

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Conjugated microporous polymers (CMPs) have been considered a type of promising visible-light-driven, organic photocatalysts. However, apart from designing high-performance CMPs from a molecular perspective, little attention is paid to improving the photocatalytic properties of these polymers through macrostructural regulation. Herein, we prepared a kind of hollow spherical CMPs involving carbazole monomers and studied their performance on the selective photocatalytic oxidation of benzyl alcohol under visible light irradiation. The results demonstrate that the introduction of a hollow spherical structure improves the physicochemical properties of the as-designed CMPs, including the specific surface areas, optoelectronic characteristics, as well as photocatalytic performance, etc. In particular, the hollow CMPs can more effectively oxidize benzyl alcohol compared to pristine ones under blue light illumination, and produce >1 mmol of benzaldehyde in 4.5 h with a yield of up to 9 mmol·g-1·h-1, which is almost 5 times higher than that of the pristine ones. Furthermore, such hollow architecture has a similar enhanced effect on the oxidation of some other aromatic alcohols. This work shows that the deliberate construction of specific macrostructures can better arouse the photocatalytic activity of the as-designed CMPs, which will contribute to the further use of these organic polymer semiconductors in photocatalysis areas.

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Developing mixed-anion semiconductors for solar fuel production has inspired extensive interest, but the nitrohalide-based photocatalyst is still in shortage. Here we report a layered nitro-halide ß-ZrNBr with a narrow band gap of ca. 2.3 eV and low defect density to exhibit multifunctionalities for photocatalytic water reduction, water oxidation and CO2 reduction under visible-light irradiation. As confirmed by the results of electron paramagnetic resonance (EPR) and density functional theory (DFT) calculations, the formation of anion vacancies in the nitro-halide photocatalyst was inhibited due to its relatively high formation energy. Furthermore, performance of ß-ZrNBr can be effectively promoted by a simple exfoliation into nanosheets to shorten the carrier transfer distance as well as to promote charge separation. Our work extends the territory of functional photocatalysts into the nitro-halide, which opens a new avenue for fabricating efficient artificial photosynthesis.

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In this study, a series of ternary composite photocatalysts ZnO/g-C3N4/AgCl(x) (x is the amount of AgCl added, x=0.05, 0.1, 0.15 g) were synthesized, and various characterization methods were used to analyze the morphology, structural, and photochemical properties of the above samples. The photocatalytic activity of the obtained samples was evaluated by degrading rhodamine B (RhB) and acid orange (AOII) under xenon lamp irradiation. The results show that the degradation rate of ZnO/g-C3N4/AgCl (0.1 g) is 99% within 60 min, which is much higher than the 38% degradation rate of g-C3N4. After five cycles, the degradation efficiency of RhB and AOII by ZnO/g-C3N4/AgCl (0.1 g) were still 85% and 94%, respectively. In addition to colored dyes, the photocatalytic degradation of colorless tetracycline hydrochloride (TCH) compounds was also investigated to understand the effect of photosensitization on the degradation process. Based on the electronic structure analysis of the DFT calculations, a staggered heterojunction structure was found between g-C3N4, ZnO, and AgCl. The enhanced photocatalytic activity of the ternary composite is mainly attributed to the efficient separation of charge carriers through the synergistic removal of photogenerated electrons in g-C3N4 by ZnO and AgCl. Radical trapping experiments confirmed that •O2- and h+ were the main active species in the reaction system. As a visible light-responsive catalyst, ZnO/g-C3N4/AgCl can be effectively applied to the degradation of organic dye pollutants and has broad application prospects.

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In this work, different proportions of N-doped carbon quantum dots/porous Co3O4 (NCQDs/p-Co3O4) NCQDs/Co3O4 composite photocatalysts were prepared by a simple self-assembly method. It was demonstrated by a series of characterizations that 50% NCQDs/Co3O4 has a good visible light response and low electrochemical impedance. The photocatalytic degradation of TC was investigated by the 50% NCQDs/p-Co3O4 composite photocatalyst, and the results showed that the degradation effect of TC reached 81.2% within 120 min. The higher photocatalytic activity of 50% NCQDs/p-Co3O4 was analyzed probably because NCQDs can improve the separation efficiency of photogenerated electron-hole pairs and p-Co3O4 can provide a larger specific surface area and thus has more active sites. This study provides a new strategy for improving the photodegradation activity of Co3O4 photocatalysts.

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In this work, a strategy of heat treatment-precipitation has been developed to recycle Ti-containing metallurgical solid waste by forming Ti-embedded MgAl layered double hydroxide (TMA-LDH). This facile and simple route is featured by the dedicated utilization of the composition of slag with high overall recovery efficiency. Importantly, as-obtained product exhibits visible light response distinctly different from that of pristine MA-LDH ascribed to the Fe doping inherited from initial slag. Its mesoporous nanostructure also provides more microchannels for mass and carrier transfer. As such, excellent photocatalytic activity towards degradation of tetracycline hydrochloride is achieved, and 88% removal could be obtained in 60 min. Furthermore, 44% increase in efficiency than that of Ti-excluded LDH also indicates the synergistically promoting effect of Ti incorporation. Mechanism investigation suggests that Ti incorporation regulates the electronic structure of pristine LDH with more active sites, and favors the formation of radicals with improved oxidative ability for photocatalysis.

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Artificial Z-scheme, a tandem structure with two-step excitation process, has gained significant attention in energy production and environmental remediation. By effectively connecting and matching the band-gaps of two different photosystems, it is significant to utilize more photons for excellent photoactivity. Herein, a novel one-photon (same energy-two-photon) Z-scheme system is constructed between rGO modified boron-nitrogen co-doped-WO3 , and coupled CdSe quantum dots-(QDs). The coctalyst-0.5%Rhx Cr2 O3 (0.5RCr) modified amount-optimized sample 6%CdSe/1%rGO3%BN-WO3 revealed an unprecedented visible-light driven overall-water-splitting to produce ≈51 µmol h-1 g-1 H2 and 25.5 µmol h-1 g-1 O2 , and it remained unchanged for 5 runs in 30 h. This superior performance is ascribed to the one-photon Z-scheme, which simultaneously stimulates a two photocatalysts system, and enhanced charge separation as revealed by various spectroscopy techniques. The density-functional theory is further utilized to understand the origin of this performance enhancement. This work provides a feasible strategy for constructing an efficient one-photon Z-scheme for practical applications.

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Intensive research has been focused on the synthesis of N-modified TiO2 materials having visible light absorption in order to get higher solar photocatalytic degradation rates of pollutants in water. However, an exhaustive revision of the topic underlines several controversial issues related to N-modified TiO2 materials; these issues concern (a) the methodology used for preparation, (b) the assessment of the structural characteristics, (c) the mechanistic action modes and (d) the raisons argued to explain the limited performances of the prepared materials for organic and biological targets photodegradation in water. Taking advantage of last year's progress in analytical chemistry and in material characterization methods, the authors show, for example, that some works in the literature controversially attribute the term nitrogen doping without enough analytical evidence. Additionally, some papers describe N-modified TiO2 photocatalysts as being able to generate holes with enough oxidative potential to form hydroxyl radicals under visible light. This last assertion often derives from a no pertinent use of illumination sources, light filters, or targets or a limited understanding of the thermodynamic aspects of the studied systems. None of N-containing materials prepared by herein presented methods leads, under solar light, to a significant enhancement in pollutants degradation and microorganism's inactivation kinetics.

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Smart hydrogels are typical functional soft materials, but their functional and mechanical properties are compromised upon micro- or macro-mechanical damage. In contrast, hydrogels with self-healing properties overcome this limitation. Herein, a dual dynamic bind, cross-linked, self-healing protein hydrogel is prepared, based on Schiff base bonds and diselenide bonds. The Schiff base bond is a typical dynamic covalent bond and the diselenide bond is an emerging dynamic covalent bond with a visible light response, which gives the resulting hydrogel a dual response in visible light and a desirable self-healing ability. The diselenide-containing protein hydrogels were biocompatible due to the fact that their main component was protein. In addition, the hydrogels loaded with glucose oxidase (GOx) could be transformed into sols in glucose solution due to the sensitive response of the diselenide bonds to the generated hydrogen peroxide (H2O2) by enzymatic catalysis. This work demonstrated a diselenide-containing protein hydrogel that could efficiently self-heal up to nearly 100% without compromising their mechanical properties under visible light at room temperature.

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The degree of polymerization in polyimides has significant effects on their photoelectric properties. Increase the degree of polymerization in polyimide can improve its light absorption capability as well as reduce the recombination rate of photogenerated electrons and holes. However, it is difficult to promote the polymerization of polyimides by conventional approaches, such as increasing the polymerization temperature since polyimides are susceptible to high temperature and can be decomposed. In this paper, a suitable proportion of phosphotungstic acid was introduced to increase the degree of polymerization of polyimide at a lower polymerization temperature, so as to improve the light absorption capability of the composite and inhibit the recombination of electron and hole. The p-phenylenediamine based polyimide with the one-dimensional linear polymer chain has excellent charge transfer ability, so the POM-π effect formed with phosphotungstic acid is stronger, correspondingly, the light absorption capacity of the composite photocatalyst formed is stronger than that of the cross-linked polyimide/phosphotungstic acid.

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In this study, different carbon quantum dots (CQDs)/NaBiO3 hybrid materials were synthesized as photocatalysts to effectively utilize visible light for the photocatalytic degradation of contaminants effectively. These hybrid materials exhibit an enhanced photocatalytic reduction of hexavalent chromium (Cr(VI)) in the aqueous medium. Zero-dimensional nanoparticles of CQDs were embedded within the two-dimensional NaBiO3 nanosheets by the hydrothermal process. Compared with that of the pure NaBiO3 nanosheets, the photocatalytic performance of the hybrid catalysts was significantly high and 6 wt.% CQDs/NaBiO3 catalyst exhibited better photocatalytic performance. We performed the first-principles density functional theory calculations to study the interfacial properties of pure NaBiO3 nanosheets and hybrid photocatalysts, and confirmed the CQDs played an important role in the CQDs/NaBiO3 composites. The experimental results indicated that the enhanced reduction of Cr(VI) was probably due to the high loading of CQDs (electron acceptor) on NaBiO3, which made NaBiO3 nanomaterials to respond in visible light and significantly improved their electron-hole separation efficiency.

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Inspired by the light-regulating capabilities of naturally occurring rhodopsin, we have constructed a visible-light-regulated Cl- -transport membrane channel based on a supramolecular host-guest interaction. A natural retinal chromophore, capable of a visible-light response, is used as the guest and grafted into the artificial channel. Upon introduction of an ethyl-urea-derived pillar[6]arene (Urea-P6) host, threading or de-threading of the retinal and selective bonding of Cl- can be utilized to regulate ion transport. Based on the visible-light responsiveness of the host-guest interaction, Cl- transport can be regulated by visible light between ON and OFF states. Visible-light-regulated Cl- transport as a chemical model permits to understand comparable biological ion-selective transport behaviors. Furthermore, this result also supplies a smart visible-light-responsive Cl- transporter, which may have applications in natural photoelectric conversion and photo-controlled delivery systems.

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An Ag/AgCl/NH2-UiO-66 hybridized photocatalyst was successfully constructed via facile solvothermal with UV reduction method for efficient photocatalytic Cr (VI) reduction. The photoelectrochemical data indicate that compared with the UiO-66, the charge separation and transfer efficiency of Ag/AgCl/NH2-UiO-66 heterojunction is significantly enhanced due to the introduction of amine functionalization and formation of inorganic-organic hybrid. The surface plasmon resonance (SPR) effect deriving from Ag nanoparticles (NPs) largely extends photo-response range whilst the separation efficiency of photo-generated electrons and holes is improved significantly. The synthesized Ag/AgCl/NH2-UiO-66 hybrid system shows ameliorated structural stability and superior photocatalytic activity for Cr (VI) reduction under visible light irradiation, which is 1.7 times higher than that of the bare UiO-66. Furthermore, the possible mechanism of Cr (VI) reduction is proposed by analyzing electron transfer path in the ternary Ag/AgCl/NH2-UiO-66 hybridized system.

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Photoresponsive cholesteric liquid crystals (CLCs) are able to selectively reflect colors upon light exposure. Yet, it still remains a formidable challenge to realize simultaneous rewriting and long-life color in CLCs using visible light. Herein, guided by time dependent density functional theory (TD-DFT) computation, an octafluorinated binaphthyl azobenzene is synthesized to achieve the fast response and long-life color upon visible light exposure. Subsequently, based on the solubility parameter, uniform CLCs are formulated through a facile co-doping strategy. Interestingly, the CLCs change reflection colors from blue to green, red, and then into the near infrared region in seconds upon 550 nm light illumination. The completely reversible process is readily accessable upon 450 nm irradiation. More importantly, each color is independently stable for ≈24 h in the dark.

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