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The enhancement of the self-cleaning ability of photocatalytic membranes and their degradation efficiency over tetracycline (TC) still remains a challenge. In this study, an alternative silver vanadate quantum dots (AgVO

5-Hydroxymethylfurfural (5-HMF), as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels, has been attracted extensive attention. In this research, using Pickering high internal phase emulsions (Pickering HIPEs) as template and functional metal-organic frameworks (UiO-66-SO3H and UiO-66-NH2)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process, which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF. The effects of the emulsion parameters including the amount of surfactant (ranging from 0.5 %(mass) to 2.0 %(mass)), the internal phase volume fraction (ranging from 75% to 90%) and the acid/base Pickering particles mass ratio (ranging from 0:6 to 6:0) on the morphology and catalytic performance of solid catalyst were systematically researched. The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion, and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield. The highest 5-HMF yield, about 40.5%, can be obtained by using polymer/MOFs composite as catalyst (Poly-P12, the pore size of (53.3 ± 11.3)μm, the acid density of 1.99 mmol·g-1 and the base density of 1.13 mol·g-1) under the optimal reaction conditions (130 ℃, 3 h). Herein, the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method, which provided a favorable experimental basis and theoretical reference for achieving efficient production of high added-value product from abundant biomass.

Separation efficiency of photogenerated carriers and CO2 adsorption ability of the catalyst are two important factors affecting the photoreduction performance of CO2. In view of the above analyses, leaf-vein like 2D-1D g-C3N4/P-MWNTs donor/acceptor semiconductor-carbon hybrid composite has been successfully prepared by the simple co-grinding/calcination processes. UV–vis DRS results showed that the modification of P-MWNTs can enhance the photo-absorption ability of the composite. Photoelectrochemical tests proved that 2D-1D Schottky-like barriers can enlarge the separation and transfer efficiency of photogenerated carriers. BET and CO2-adsorption tests exhibited that the introduction of P-MWNTs can greatly increase the CO2 capture ability of the composite. CO2 photoreduction experiments confirmed that the composite had much more excellent CO2 photoreduction performance than the pure g-C3N4 under the irradiation of UV–vis light or visible light. In-situ FTIR and 13C isotope tracer tests were applied to research the CO2 photoreduction processes. Finally, the synergistic effect on CO2 photoreduction process between electron transfer and CO2 adsorption behavior has been discussed in total.

Wide-light absorption performance and efficient carrier separation ability are the necessary conditions for excellent photocatalytic materials. In this research, g-C3N4 QDs (CN QDs) and Au nano-particles (NPs) co-modified CeO2/Fe3O4 micro-flowers (MFs) photocatalyst (CACeF) has been prepared. CO2 photoreduction experiments showed that the composite had obviously enhanced photoreduction activity and photocatalytic stability. The yields of CO and CH4 over it as catalyst in 4 h is about 5 and 8 times greater than that of pure CeO2. Photoelectrochemical tests showed that the heterojunction between CN QDs and Au NPs can greatly improve the carrier separation ability and the light-utilization efficiency of photocatalysts. Besides, the excellent electronic transmission performance of Au NPs provided a specific channel for the electron transmission, and the strong local surface plasmon resonance (LSPR) of Au NPs resulted in a lot of hot-electrons can directly take part in the CO2 photoreduction. The synergistic effect between CN QDs and Au NPs can further enhance the photocatalytic activity of the photocatalyst. Fe3O4 QDs can ensure the effective recovery and reuse of the composite without affecting the photocatalytic performance of composite. Finally, a potential photoreduction mechanism of CN QDs and Au NPs co-modified CeO2/Fe3O4 MFs photocatalyst were discussed in total.

The design and development of high-performance photocatalysts from three aspects of simultaneous enhancement of light harvest, carrier migration rate, and redox reaction rate is still a great challenge. Herein, a novel Co9S8/CdIn2S4 ohmic junction with a robust internal electric field (IEF) is successfully prepared via hydrothermal and in situ synthesis methods and is used for effective photocatalytic H2 evolution (PHE). Under simulated visible light irradiation, the PHE rate of 5% Co9S8/CdIn2S4 can reach 1083.6 μmol h−1 g−1, which is 6.4 times higher than that of CdIn2S4 (170.5 μmol h−1 g−1). The enhanced PHE performance is mainly ascribed to the improved light harvest and carrier separation efficiency and fast surface H2 evolution kinetics. Moreover, Co9S8 nanotubes serve as promising Co-based cocatalysts that can evidently enhance PHE activity. Additionally, Co9S8/CdIn2S4 shows superior stability because the photogenerated carrier transfer path restrains the photocorrosion behavior. The photocatalytic mechanism is proposed based on experimental results and DFT calculations. This work offers new insights for the design and development of highly active photocatalysts from interface engineering.

Photocatalytic materials can be used as self-cleaning functional materials to alleviate the irreversible fouling of ultrafiltration membranes. In this work, the small size g-C3N4/Bi2MoO6 (SCB) blended polysulfone (PSF) ultrafiltration membranes was fabricated by hydrothermal and phase inversion methods. As a functional filler of ultrafiltration membranes, the small size g-C3N4 nanosheet decorated on the surface of Bi2MoO6 can enhance the photocatalytic performance for bovine serum albumin (BSA) degradation, and remove irreversible fouling under visible light irradiation. In addition, the introduction of SCB microspheres into PSF matrix obviously increased the porosity of ultrafiltration membranes. Therefore, the SCB-PSF ultrafiltration membranes displayed excellent antifouling performance (flux recovery ratio is 82.53%) and BSA rejection rates (94.77%). SCB-PSF also had high photocatalytic self-cleaning activity, indicating excellent application prospects in organic wastewater treatment.

Photocatalytic conversion of CO2 into hydrocarbon fuels is an ideal technology of mitigating greenhouse effect caused by excessive emission of CO2. However, the high recombination rate of electron-hole pairs and limited charge carriers transport speed constrained the catalytic performance of many semiconductor catalysts. In this contribution, a series of carbon nitride (g-CN) samples with intramolecular donor-acceptor (D-A) system were successfully prepared by introducing organic donor into their structures. Characterization results confirmed that carbazole was successful connected to the structure of g-CN via chemical bond. The formation of intramolecular D-A system greatly enlarged the light response region of g-CN-xDbc. In addition, a new charge transfer transition mode was formed in g-CN-0.01Dbc due to the incorporation carbazole, which enable it to use light with energy lower than the intrinsic absorption of g-CN. Meanwhile, the D-A structure led to the spatial separation of electrons and holes in g-CN-xDbc and significantly decreased the recombination rate of electron-hole pairs. The g-CN-0.01Dbc presented the best catalytic performance and the CO evolution rate was 9.6 times higher than that of g-CN. Moreover, the reaction was performed in water without any additive, which made it green and sustainable. DFT simulation confirmed the D-A structure and charge carrier migration direction in the prepared samples.

Effectively separating photo-generated charge carriers is usually important but difficult for the high-activity photocatalysis. Fabricating 2D/2D Schottky-Ohmic junction is more beneficial to the spatial separation and transfer of photo-induced charges at the interface of different components due to the matching of distinct two-dimension structure and band alignment, but the manipulation and mastery of junction type (Schottky-Ohmic junction and Z-scheme junction) and electronic structure is an arduous task for preparing satisfactory photocatalysts and investigating the PHE mechanism. In this work, the 2D/2D WO3/Pt/g-C3N4 (WPC) Schottky-Ohmic junction composite photocatalysts is formed via facile hydrothermal and photo-induced deposition method for employing to produce H2. The optimized WPC Schottky-Ohmic junction photocatalyst exhibits remarkable photocatalytic H2-release performance with ability to produce the amount of H2 reaches 1299.4 μmol upon exposure to visible light, which is about 1.2 and 11.5 times higher than that of WO3/g-C3N4/Pt (WCP) (1119.4 μmol) and pure CN (113.2 μmol)), respectively. This remarkable enhancement of photocatalytic performance is ascribed to: (i) Schottky-Ohmic junction can strikingly expedite spatial charge separation and elongate electron lifetime, (ii) the 2D/2D structure can shorten the charge transportation distance, (iii) Pt with rich electron density can stably adsorb H+. This work provides a successful paradigm for future fundamental research, and exquisitely designs ideal g-C3N4-based photocatalysts by simultaneously adjusting and optimizing material structure and electronic dynamics.

Control and insight into the abundance of inter-shelled channel active sites and charge transport mechanism are the long-term challenges for enhancing photocatalytic activity. Herein, the Ni2P quantum dots (QDs) are decorated in the multi-shelled CaTiO3 cube for creating the abundance of inter-shelled channel active sites, which greatly improve the photocatalytic performances for generating H2 and degrading tetracycline (TC) relative to pure CaTiO3 and Ni2P. Moreover, the Z-scheme mechanism and the quantum effect of the Ni2P in multi-shelled CaTiO3 cube play a crucial role for enhancing photocatalytic performance. Furthermore, the photoelectric researches demonstrate that the Ni2P/CaTiO3 heterostructure possesses more abundant active sites, smaller interface transmission resistance and faster photo-generated charge transfer efficiency. This work provides a meaningful model to research other materials with creating the abundance of inter-shelled channel active sites for the photo-electrocatalytic field.

In the practical process of photocatalytic H2 evolution, optimizing the ability of light absorption and charge spatial separation is the top priority for improving the photocatalytic performance. In this study, we elaborately engineer neoteric g-C3N4 nanotube@polydopamine(pDA)/NiCo-LDH (LPC) composite photocatalyst by combining hydrothermal and calcination method. In the LPC composite system, the one-dimensional (1D) g-C3N4 nanotubes with larger specific surface area can afford more active sites and conduce to shorten the charge migration distance, as well as the high-speed mass transfer in the nanotube can accelerate the reaction course. The g-C3N4/NiCo-LDH type-II heterojunction can efficaciously stimulate the spatial separation of photo-produced charge. In addition, pDA as heterojunction metal-free interface mediums can provide multiple action (π-π* electron delocalization effect, adhesive action and photosensitization). The optimized LPC nanocomposite displays about 3.3-fold high photoactivity for H2 evolution compared with the g-C3N4 nanotube under solar light irradiation. In addition, the cycle experiment result shows that the LPC composite photocatalyst possesses superior stability and recyclability. The resultant g-C3N4@pDA/NiCo-LDH composite photocatalyst displays the potential practical application in the field of energy conversion.

Achieving the intelligent controllability of the photocatalyst to the surrounding environment is a very meaningful work. Here, the polyacrylic acid (PAA) modified Ag/AgCl-40/CN composite was constructed to achieve an intelligent response of pH value. PAA exhibits hydrophilic properties at high pH value, increasing the adsorption capacity to tetracycline (TC) molecules. The morphology of PAA from contracted state to diastolic state, releasing the Ag/AgCl-40/CN catalyst. In addition, PAA modified Ag/AgCl-40/CN can prevent the loss of AgCl. The g-C3N4 nanosheets (CN) as a carrier enhance the dispersibility of the AgCl particles. The LSPR effects of Ag nanoparticles produce more electrons acting on photocatalytic degradation. On the results of experiment, the degradation of TC by PAA@Ag/AgCl-40/CN shows an excellent degradation activity when the high pH value. Photoluminescence spectroscopy and photocurrent demonstrate that carrier separation efficiency of PAA@Ag/AgCl-40/CN is higher than CN and Ag/AgCl-40/CN. The detection of the main active substances •O2− and h+, revealing a reasonable mechanism for the PAA@Ag/AgCl-40/CN hybrid system. This work provides a procedure to obtain smart materials that can switch photocatalytic processes.

Development of high-efficiency separation materials with specific recognition sites has become an urgent and important task. Herein, a synergetic strategy based on polydopamine (pDA) and silicon dioxide nanoparticles (SiO2) was successfully designed and developed for the preparation of imitated core-shell-based cloxacillin-imprinted nanocomposite membranes (ICCIMs-D/S). Cloxacillin (Col) was selected as the template resulting from the potential threat to environment and human health. As to the synthesis procedure of ICCIMs-D/S, the pDA-modified layers were uniformly loaded onto substrate membranes by developing an elevated phase transformation method. Based on it, the synergy processes of pDA and SiO2 could be achieved on surface of porous membranes. The ICCIMs-D/S with Col-imprinted recognition sites were finally synthesized by the photo-initiated “mercapto-alkenes click chemistry” method using methacrylic acid as functional monomers. Notably, the satisfactory rebinding selectivity (α>4.0) and permselectivity (β>4.0) with outstanding regeneration performance (only 5.11% decrease after ten regeneration cycles) indicated the superior selectivity and stability of the as-obtained ICCIMs-D/S. The preparation strategy and ICCIMs-D/S developed in this work is expected to provide a feasible idea for selective separation of Col from wastewater.

Defect structure is one of the crucial factors for enhancing the catalytic activities of photocatalysts. However, rational design and construction of defect structures in catalysts to meet the aim of enhancing photocatalytic performance in a simple and cost-effective way is still a challenge. In this contribution, we report a strategy to construct defect structures in graphitic carbon nitride (g-CN) by simple copolymerizing of urea with polyethyleneimine (PEI). Among the prepared catalysts, u-0.05PEI presents the best photocatalytic activity for CO2 reduction, with CO and CH4 yields of 32.86 and 1.68 μmol g-1 in 4 h, which is about 3.2 and 2.5 times higher than that of g-CN, respectively. Characterization results show that both C and N defects are formed in the newly prepared catalysts. The C defects on the surface of u-xPEI result in the formation of more amino groups which are beneficial for CO2 adsorption. Meanwhile, the N defects inside the samples lead to the generation of midgap states between the valance band and conduction band of u-xPEI. The midgap states greatly enlarge the light absorption extent, and enable the use of light with energy lower than the intrinsic absorption of g-CN in the photoreduction of CO2. As confirmed by DRS, EPR, PL analysis, the excellent catalytic activity of u-0.05PEI is mainly attributed to the remarkably improved light utilization efficiency and fast charge transfer. Moreover, the reaction is performed in water without any additive or organic solvent, which makes it environmentally friendly.

It is extremely important for photocatalysts to exhibit intelligent responsiveness to their environment. Herein, a poly N-isopropyl acrylamide (PNIPAM)-modified Ag/Ag3PO4-20/CN hybrid material with excellent convertible photocatalytic activity is prepared. PNIPAM has good hydrophilicity below the lower critical solution temperature (LCST); this increases the capacity of the photocatalyst for adsorbing tetracycline (TC) molecules. In addition, the PNIPAM-modified Ag/Ag3PO4-20/CN can prevent the loss of Ag3PO4. The dispersity is improved by loading g-C3N4 nanosheets (CN) for enhancing the efficiency of photocatalytic activity. Furthermore, a Z-scheme heterostructure is formed between CN and Ag3PO4, accelerating the separation efficiency of the holes and electrons. Ag nanoparticles can be used as electron-shuttle mediators, and electrons receiving more energy are transferred via the localized surface plasmon resonance (LSPR) effect. Furthermore, the PNIPAM@Ag/Ag3PO4-20/CN photocatalyst exhibits an excellent degradation rate for the degradation of TC when the temperature is lower than the LCST. The photoluminescence spectra and photocurrent curves prove that the carrier-separation efficiency of PNIPAM@Ag/Ag3PO4-20/CN is higher than those of Ag/Ag3PO4/CN and CN. The main active species of ·O2− and h+ are detected to reveal the plausible mechanism of the PNIPAM@Ag/Ag3PO4-20/CN hybrid material system. This work provides a way to develop intelligent materials for switchable photocatalytic applications.

Developing advanced multifunctional carbon-based materials to achieve deep purification of environmental pollutants for practical environmental remediation are highly desired. Herein, we reported a novel 3D sea urchin-like hybrid architectures with Co nanoparticles (NPs) embedded in Co/N co-doped carbon nanotube supported on hollow frameworks (CoNC/CNTs), which derived from core-shell ZIF-67/ZIF-8 via epitaxial growth-pyrolysis strategy. Benefiting from the synergistic effects of 0D Co nanoparticles, 3D nitrogen doping, hierarchically hollow structures, and 1D interconnected N CNTs, forming a diversity of active interfaces to enhance the overall property. As expected, the resulting CoNC/CNTs exhibited ultrahigh adsorption capabilities of organic dyes, including methyl blue (8862.5 mg/g), acid fuchsin (8032.2 mg/g) and malachite green (6043.2 mg/g), respectively, which outperformed the majority of the previously reported materials, as well as superior catalytic activities toward recalcitrant pollutants in peroxymonosulfate (PMS) activation, including bisphenol A, phenol, tetracycline and sulfamethoxazole. A series of characterization methods confirmed that chemical compositions affected the morphologies, adsorption and catalytic properties of CoNC@CNTs. Notably, CoNC/CNTs maintained good reusability and stable activity even after five cycles with negligible leaching of cobalt ions. More significantly, this work provided a new strategy for the practical applications of MOFs derived TM@N C composites in environmental remediation.

Photocatalysis is an attractive and green strategy for organic pollutant removal. The development of alternative and effective photocatalysts has attracted great attention. Herein, we rationally engineer an alternative rich-oxygen vacancies (OVs) Bi2WO6/In2O3 composite photocatalyst via integrating the calcination and hydrothermal method for removing organic dyes (rhodamine B). Thanks to the synergistic effect of OVs and heterojunction structure, the 80 wt% Bi2WO6/In2O3 (BiIn80) displays enhanced photocatalytic degradation effect. The degradation rate of BiIn80 is up to 97.3% under light irradiation within 120 min and the reaction rate constant k value (0.03221 min−1) is about 15-fold and 4.17-fold as high as those of In2O3 (0.00203 min−1) and Bi2WO6 (0.00772 min−1), respectively. The heterostructure of Bi2WO6/In2O3 can extend the lifespan of the photogenerated charge carriers. Moreover, the density functional theory (DFT) calculations reveal that the OVs in Bi2WO6/In2O3 can boost visible light absorbability by decreasing band gap value and serve as the extra electron transfer channels to enhance the separation efficiency of photogenerated electron-hole pairs. This study not only provides an alternative route for fabricating highly efficient heterojunction photocatalysts, but also obtains better understanding of the synergistic effect of OVs and heterojunction on enhancing the photocatalytic performance.

Efficient incorporation of large-mesoporous silica materials with the film structure to fabricate hybrid film materials has been promising for water treatment. The modified large-mesoporous silica films possessed superior adsorbability, but the poor mechanical behavior hampered the application of adsorbents. We proposed the fabrication of La modified rGO/silica mesoporous films for efficient phosphate removal to deal with this problem. Consider the problem of plugging of mesopores, La/Si molar ratio of 1/10 was a conventionally reported loading ratio in the literatures. In this paper, the film materials also retained pore size (19.97 nm) comparable with that of the pristine large-mesoporous silica films (20.53 nm) when the La/Si molar ratio was 1/5. In the adsorption experiments, the maximum phosphate capacities achieved 55.045 mg g−1. And multi-adsorption mechanisms were confirmed by the results of analysis. The formation of rod-like crystal LaPO4 was the main pathway in the adsorption process. The film material might create a new way for phosphate removal.

Membranes with special wettability (superhydrophobic/superoleophilic or superhydrophilic/superoleophobic) had been introduced to separate oil/water emulsions. Nevertheless, the surface or pore canals of membrane easily fouled by oily wastewater are the tough challenges towards longtime application. In this work, a PVDF@PDA@ZnO membrane was firstly fabricated via growth of ZnO nanoparticles from ZnO seeds planted on the PVDF@PDA membrane. This PVDF@PDA@ZnO membrane showed good separation capability for various emulsions (which the separation efficiencies and fluxes were up to 99.1% and 654 L m − 2 h − 1, respectively). The degradation rate of MB solution treated by the composite membrane was almost 100% attributing to the excellent photocatalytic ability of ZnO. Moreover, the composite membrane could maintain high efficiency (above 99.27%) after long-time emulsions separation/UV-light irradiation, which displayed superior UV-driven self-cleaning and oxidation resistance performance. This self-cleanable composite membrane possessed durability and held high promise for long-time oil/water emulsions separation.

To completely utilize the high redox ability of photo-induced charge carriers. Here, a Z-scheme photocatalyst of TiO2 QDs/Bi12TiO20 (TBT) composites with TiO2 QDs fragment attached to the surface of Bi12TiO20 (BTO) was prepared and the photocatalytic activity was evaluated by degradation of gatifloxacin (GF). The optimal photocatalytic performance of TBT displayed 3 times higher than bare BTO. The improved photocatalytic performance was ascribed to the effective separation of the charge carriers between TiO2 QDs and BTO via the direct Z-scheme heterojunction. Such a strategy for the construction of Z-scheme TBT composites for removal of organic pollutants, proving new insights into design photocatalyst.

Oily wastewater has increasing in recent decades due to industrial production and domestic wastewater. Conventional techniques for oil/water separation such as adsorption, magnetic and combustion suffer from high cost, low efficiency and low regenerability, especially, a large number of oil droplets are embedded in the inner of the membrane, blocking the hole of the membrane so that the membrane cannot be reused. To solve these problems, we synthesized a flower-like visible light driven antifouling membrane, the resultant membrane manifested excellent superhydrophilicity with WCA was 0° and underwater superoleophobicity with underwater OCA was 158° More importantly, the developed membrane exhibited a favorable separation efficiency of 99.5% to separate a serious of oil/water mixtures. Remarkably, the membrane presented superior antifouling performance which maintained separation efficiency of 99% under visible driven even after 140 oil/water separations cycles. The avant-garde membrane was investigated in the work hope to become a promising candidate for oil/water separation.

In this work, a biofiber was used as the natural polymer carrier to design a BiVO4 QDs/cellulose fiber composite for photocatalytic application. The biofiber was obtained from bamboo, which was green, abundant and short growth cycle in Asia. Naturally rich groups of biofiber provided many sites to absorb the Bi3+ to form the uniform distribution for BiVO4 QDs. Moreover, a series of results indicated the strong connection was formed between biofiber and BiVO4 QDs, which could increase the stability and electron transfer. Therefore, the new composite photocatalyst exhibited better stability and effectively photocatalytic activity. Moreover, the possible mechanism of synthesis and photocatalytic were discussed, which provided insight for synthesizing photocatalytic based on biomaterials.

The development of superhydrophilic/underwater superoleophobic membrane is significant for purification of emulsified oily wastewater. However, low flux and membrane fouling still remains a challenge. Herein, a sisal-like structured hybrid membrane is prepared through in situ growth of nickel cobalt layered double hydroxide (NiCo-LDH) microcrystals on membrane surface for oil/water emulsion separation. The as-prepared hybrid membrane (CN@pDA@PVDF) exhibits low oil adhesion, outstanding antifouling performance and superhydrophilicity/underwater superoleophobicity. Under gravity driven, the separation experimental results demonstrate the as-prepared membrane can effective separate surfactant-free emulsion (SFE) and surfactant-stabilized emulsion (SSE) with separation efficiency of above 99.4%. Furthermore, with a simple and low cost approach, as well as the significantly enhanced performance, the as-prepared hybrid membrane has bright application prospective in wastewater treatment.

The kernel of photocatalytic technology is to exploit photocatalytic materials with high efficiency, stability and easy recovery. Herein, we designedly prepare a magnetic quantum dot (Fe3O4 QDs) as co-catalyst to modify Z-scheme Bi2O4/g-C3N4 (Bi/CN) composite photocatalyst via combining calcination with hydrothermal method. The morphology, chemical composition and physicochemical properties of photocatalysts are systematically analyzed by a series of characterization means. The experimental results explicitly render that the optimum Fe3O4-QDs/Bi2O4/g-C3N4 (FeQDs/Bi/CN) has outstanding photocatalytic performance than that of Bi2O4, g-C3N4 and Bi2O4/g-C3N4 (Bi/CN), which is chiefly imputed to the synergistic effect of Z-scheme heterojunction system and Fenton reaction. The Z-scheme heterojunction is conductive to accelerate charge carrier separation and makes electrons and holes retain higher redox ability. Fe3O4 QDs can promote visible light absorption and generate more hydroxyl active ( OH) substances through Fenton reaction. Furthermore, the magnetic photocatalyst is liable to separate under the action of external magnetic field, which ensures that is convenient for industrial application. The mechanism of photocatalytic degradation is discussed in detail by capturing experiments, ESR and liquid fluorescence detection. This work unveils more possibilities for modifying Z-scheme heterojunction system to improve photocatalytic performance.

2D/2D heterojunction photocatalyst of CdIn 2 S 4 on nitrogen doped reduced graphene (N-rGO) was fabricated by in situ hydrothermal method. It is noticeable that the flower-like CdIn 2 S 4 photocatalyst composed of film is controlled by the temperature of synthesis process. When CdIn 2 S 4 photocatalyst load on N-rGO, irregular film N-rGO functions as support to disperse the CdIn 2 S 4 , forming the 2D/2D interfacial structure, which is confirmed by SEM, TEM, HRTEM. When the mass fraction of N-rGO is 10%, the binary composite photocatalyst could photodegrade 80% 50 mg/L 2,4-dichlorophenol (2,4-DCP). That is because the heterojunction formed between CdIn 2 S 4 and N-rGO promotes the electron transfer, especially the interfacial contact region. What's more, the N-rGO can efficiently accumulate the 2,4-DCP molecules because of its unique structure, bettering the contact rate between 2,4-DCP and the whole photocatalyst. The possible mechanism of photodegrading 2,4-DCP was discussed and investigated. This work highlights the synergistic effect, especially the harmony between charge transfer and active sites to benefit the photocatalytic performance.

Photocatalytic technology provides a new strategy for the treatment of water pollution and energy crisis. Developing photocatalytic materials with high efficiency and stable visible light response has always been the direction of scientific researchers in the photocatalytic field. In this paper, we designed and prepared an efficient and stable rGO-modifited type-I Ag2S/g-C3N4 heterojunction photocatalyst (rGO/Ag2S/CN). The TEM (Transmission electron microscope) technology shows that the morphology of rGO/Ag2S/CN is a sandwich-like structure. UV–Vis DRS (UV–visible diffuse-reflectance spectrum) shows that the loading of Ag2S NPs and the modification of rGO effectively enhance the light response performance of nanocomposite materials in visible light. PL (Photoluminescence) and PEC (Photoelectrochemical) results prove that the photogenerated carriers transport and separation efficiency of rGO/Ag2S/CN have been improved. The photodegradation of RhB and the photoreduction of CO2 results confirmed that this ternary nanocomposite has great photocatalytic activity. The photodegradation efficiency of the RhB aqueous solution is about 98.5% after 30 min under the visible light irradiation. The photoreduction experiments showed that the yields of CO and CH4 are 178.05 μmol/g and 121.11 μmol/g, respectively after 8 h under the UV light irradiation. The results of cyclic photocatalytic experiments and the XRD pattern after those processes further revealed that the modification of rGO not only enhanced the photocatalytic performance of the nanocomposite photocatalyst, but also effectively improved the stability of Ag2S in the photocatalytic process. The possible photocatalytic reaction mechanisms were discussed in detail.

High selectivity and fast charge separation are two important factors for photocatalytic wastewater treatment. Herein, we prepared a molecular imprinted Ag/Ag3VO4/g-C3N4 photocatalyst (MIP) that exhibited great specific recognition ability along with excellent photocatalytic activity. The ultrathin g-C3N4 nanosheets with high surface are used to prepare. The Z-scheme Ag3VO4/g-C3N4 heterostructure and the surface plasmon resonance of the photoreduced Ag0 together contributed to the improvement of the separation efficiency of photogenerated electrons and holes. In addition, MIP provides the specific recognition ability to preferentially adsorb the target pollutant. The selectivity of photocatalysis was evaluated by the degradation of oxytetracycline and tetracycline solutions. Photoluminescence and transient photocurrent measurements further prove the improved charge separation efficiency of MIP. A plausible photocatalytic reaction mechanism is proposed based on electron spin resonance measurement and the active species trapping experiments, where indicates that the main active species of this photocatalytic process are O2- and h+. This research provides an effective strategy for the simultaneous enhancement of selectivity and activity via molecular imprinting.

In order to achieve the rational use of biomass resources and obtain efficient visible-light-responsive photocatalysts, the CQDs/Bi2WO6/Cu2O is firstly synthesized, and exhibits excellent degradation activity under visible light for tetracycline (TC) degradation. The excellent photocatalytic performance of CQDs/Bi2WO6/Cu2O is due to the heterojunction of Bi2WO6/Cu2O which can effectively promote the separation of electron-hole pairs. Meanwhile, the up-conversion effect of CQDs can enrich electrons and orient conductive electrons. Moreover, the possible photocatalytic mechanisms including transfer behaviors of charge carriers, generation reactive species, degrading intermediate products of TC are revealed in depth. This work may provide a new strategy for designing high stability and strong visible-light-response photocatalysts utilizing earth-abundant and low-cost natural materials.

Ratiometric fluorescent sensors have shown great prospect in chemical monitoring and recognition due to its high intuitiveness, accurateness, and visualization. In this work, the ratiometric fluorescent sensors, which includes a blue fluorescent Carbon quantum dots (CQDs) as internal standard material, and a red fluorescent boric acid-modified CdTe QDs as response signal. Then we choose dopamine (DA) as template, 3-phenylboronic acid (APBA) for functional monomers, tetraethyl orthosilicate (TEOS) for cross-linker to synthesize double ratio molecularly imprinted polymers (DR-MIPs) that can identify dopamine selectively and sensitively. The DR-MIPs has better capability of selective recognition, obvious anti-ion interference, rapid detection and good visualization. Furthermore, the unique DR-MIPs was proved as efficient visual sensors for determination of DA in human serum rapidly and efficiently. The DR-MIPs still displayed well accuracy, and the potential prospects of this smart sensor is clearly demonstrated in the context of modern clinical medicine.

In this paper, one pot-economical approach for in-situ modification of enoxacin (EXC) imprinted nanocomposite membrane was developed by employing carbon nanosphere sol (CNS) as coagulation bath during phase inversion process for increasingly antifouling property. Using polydopamine (pDA) as hydrophilic coating layer and second-reaction platform, the CNS based biomimetic molecularly imprinted nanocomposite membranes (CBMIMs) were then obtained which used EXC as the target molecule for specific adsorption and separation EXC from the sewage. The imprinting polymer layer was highly hydrophilic, which advanced antifouling performance to avoid the adsorption of contaminant protein. Using EXC as template, the optimal fabrication conditions on performances and properties of CBMIMs were studied. Isothermal adsorption curves, adsorption kinetics and rebinding selectivity were investigated to well explain the selectivity adsorption mechanism of imprinted membranes on EXC. The CBMIMs presented highly selective specificity, short kinetic equilibrium time and preferable rebinding capacity for EXC. The rebinding ability and imprinted factor (β) of CBMIMs could reach 32.10 mg g−1 and 3.15, respectively, which presented various highly favorable features, including high rebinding strength and excellent selective performance. Furthermore, the adsorption of actual environmental sewage by CBMIMs was investigated, which highlighted the advantage of CBMIMs. Several favorable performances of CBMIMs also provided further application for sewage treatment in the future.

Designing and developing an efficient photocatalytic system for degrading organic pollutants was a research hotspot in the field of environmental governance. In this study, a novel Bi2WO6/In(OH)3 composite photocatalyst was first fabricated via facile calcination-hydrothermal synthesis method. The 9-Bi2WO6/In(OH)3 composite had superior photocatalytic performance for degrading the 2-Mercaptobenzothiazole (MBT) under visible-light irradiation. The degradation rate constant of 9-Bi2WO6/In(OH)3 was 0.02192 min−1, which was 2.3 times than that of pure Bi2WO6 (0.00948 min−1). The improvement in photocatalytic performance was due to the synergistic effect of the surface heterojunction and the electron-transfer medium. The density functional theory (DFT) showed that the difference in energy levels between the conduction bands and valence bands of Bi2WO6 nanocubes (010) and (001) could build the surface heterojunction, which was in favor to promote the electron-hole pairs separation. And the In(OH)3 not only acted as a supporter to prevent the agglomeration of small size Bi2WO6 nanocubes, but also served as electron-transfer mediator to inhibit the recombination of electrons and holes. This study provided a reference value for the development and utilization of Bi-based photocatalysts. Considering the properties and structural characteristics of Bi-based photocatalysts and hydroxides, Bi2WO6/In(OH)3 composite photocatalysts were design reasonably, which provided a variety of the types of photocatalysts.

The sensitive monitoring and rapid removal antibiotics residues are great challenges and hugely significant for the environmental protection. In this work, a green and facile strategy was obtained for the fabrication of highly fluorescent carbon dots (CDs) through hydrothermal treatment of osmanthus fragrans leaves as carbon source and polyethyleneimine as nitrogen source. Then the prepared blue CDs were combined with red CdTe quantum dots (QDs) for constructing MIPs@CdTe/CDs@SiO2 was applied to selectively and sensitively assay ciprofloxacin (CIP) and TiO2/CDs/CdTe QDs as photocatalyst for the degradation of CIP. Under optimum conditions, MIPs@CdTe/CDs@SiO2 has exhibited lower detection limit of 0.0127 nM with the linear range of 0–60 nM, and successfully applied to monitor CIP in human urine samples. Moreover, the TiO2/CDs/CdTe QDs also displayed good photocatalytic degradation of activity to CIP under sunlight irradiation. This present work which was rational constructed materials based on CDs and CdTe QDs illustrates the great practicability and potential to rapid and efficient determination and removal environmental pollutants in the future.

Herein, we report a novel ternary material comprised of Ag nanoparticles and carbon quantum dots (CDs), which are co-loaded using 2D Bi4Ti3O12 (BIT) sheets. In this system, Ag can be applied as excited electron-hole pairs in the Bi4Ti3O12 by transferring the plasmonic energy from the metal to the semiconductor. The surface plasmon resonance of Ag can promote the electron transfer properties of the CDs, thereby improving the separation efficiency of the electron-hole pairs. Meanwhile, the CDs can act as an electron buffer to decrease the recombination rate of the electron hole. Moreover, CDs are prepared using a biomaterial, which can provide a chemical group to enhance the electron transfer and connection. The synergistic effects of CDs, Ag, and BIT enable the design of a photocatalytic application with a remarkably improved efficiency and operational stability.

In this paper, a simple in-suit method was used to load CdSe quantum dots (QDs) onto HTC (abbreviated as Hydrothermal biochar, HTC) to form CdSe/HTC composites. Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy were used to detect and analyze the surface valence and composition of CdSe/HTC composites. The photocatalytic degradation activity was judged by photodegrading tetracycline (TC). Compared with pure CdSe quantum dots, the best photocatalytic degradation efficiency of CdSe/HTC complex containing 15% HTC was 73%, which was attributed to the high carrier transport efficiency of HTC and the inhibition reorganization of photogenerated electron-hole pairs. More importantly, the hydrothermal biochar used in this paper was extracted from waste biomass and had the characteristics of economy, environmental protection and high utilization rate, and was in line with the basic viewpoint of sustainable use of resources.

Realization of fast, efficient and continuous oil–water separation is of great significance for solving the problem of oil pollution. We present here a facile hydrothermal strategy to synthesize a superhydrophilic platanus fruit-like Ni@Ni(OH)2 hierarchical architecture (SI-PFHA). Additionally, superhydrophobic platanus fruit-like Ni@Ni(OH)2 hierarchical architecture (SO-PFHA) is obtained through stearic acid modification of SI-PFHA. Dual-channel separation system is integrated based on two superwetting membranes. Such separation system is competent for continuous light/heavy oil–water separation with high flux and high separation efficiency. Importantly, outstanding durability and reusability make this separation system a promising strategy for practical application in remediation of oily wastewater.