High performance transparent conductive cellulose-based nanopaper (TCCNP) with long-term durability is a predominant alternative for the upscale production of next-generation green flexible electronics. Here, dual-layered TCCNP with excellent mechanical robustness and chemical stability was successfully assembled by tight binding between the mussel-inspired polydopamine functionalized nanofibrillated cellulose (PDA@NFC) substrate and the silver nanowire (AgNW) layer. The highly adhesive PDA coatings on the NFC surface uniformly connected AgNW networks and simultaneously soldered the wire-to-wire junctions, thus dramatically increasing the overall electrical conductivity. The as-prepared TCCNP possesses exceptional optoelectronic properties with an optical transmittance of 90.93% at a wavelength of 550 nm and a sheet resistance of 14.2 Ω sq−1. Meanwhile, the TCCNP displays excellent mechanical stability with negligible changes in optoelectronic performances even after 1000 bending cycles and 100 peeling tests. Furthermore, the TCCNP exhibits outstanding air and chemical corrosion stabilities after being exposed to air for 150 days or immersed in different solutions for 180 min, and its transparent conductive performance remains constant close to its initial values, which is superior to those of NFC–AgNW TCCNP without PDA or the commercial ITO/PET transparent conductive films (TCFs). More importantly, the ease of disposal of TCCNP and its good stability can greatly contribute to its application in multifunctional electronic and photoelectric flexible devices.

We designed a unique and novel bio-nanoplatform based on Pt–Ni nanoframes (PNnf) functionalized with carbon dots via the EDC/NHS coupling chemistry. The PNnf with open three-dimensional surfaces exhibited excellent water solubility after polyethylenimine modification. Due to low cytotoxicity and excellent biocompatibility, the bio-nanoplatforms were firstly used for MCF-7 cell imaging in vitro. More importantly, the design strategy can be readily generalized to facilitate other multi-functional bio-nanoplatforms for biological and biomedical applications.

Ultrathin graphite-like carbon nitride (g–C3N4) nanosheets have attracted considerable attention due to the enhanced intrinsic photoabsorption and photoresponse with respect to bulk g–C3N4. For the first time, a dual-mode of down- and upconversion luminescent g–C3N4 nanopaper with high optical transparency and mechanical robustness was successfully fabricated through a simple thermal evaporation process using chitosan as a green cross-linking agent. The dual-mode of down- and upconversion fluorescence emission originated from the amino terminated ultrathin g–C3N4 nanosheets functionalized with carboxylic acid modified multicolored rare-earth upconversion nanoparticles (cit–UCNPs) via EDC/NHS coupling chemistry. The homogeneously distributed cit–UCNPs@g–C3N4 nanoconjugates with excellent hydrophilicity displayed good film-forming ability and structural integrity; thus, the photoluminescence of each ingredient was substantially maintained. Results indicated that the freestanding chitosan cross-linked cit–UCNPs@g–C3N4 luminescent nanopaper possessed high transmittance, excellent mechanical properties, and remarkable dual-mode emission. The smart design of high performance luminescent nanopaper based on ultrathin g–C3N4 nanosheets grafted with multicolored UCNPs offers a potential strategy to immobilize other multifunctional luminescent materials for easily recognizable and hardly replicable anticounterfeiting fields.Keywords: chitosan; dual-mode luminescent nanopaper; mechanical properties; rare-earth upconversion nanoparticles; ultrathin g−C3N4 nanosheets

Flexible free-standing carbonized cellulose-based hybrid film is integrately designed and served both as paper anode and as lightweight current collector for lithium-ion batteries. The well-supported heterogeneous nanoarchitecture is constructed from Li4Ti5O12 (LTO), carbonized cellulose nanofiber (C–CNF) and carbon nanotubes (CNTs) using by a pressured extrusion papermaking method followed by in situ carbonization under argon atmospheres. The in situ carbonization of CNF/CNT hybrid film immobilized with uniform-dispersed LTO results in a dramatic improvement in the electrical conductivity and specific surface area, so that the carbonized paper anode exhibits extraordinary rate and cycling performance compared to the paper anode without carbonization. The flexible, lightweight, single-layer cellulose-based hybrid films after carbonization can be utilized as promising electrode materials for high-performance, low-cost, and environmentally friendly lithium-ion batteries.Keywords: cellulose nanofiber; in situ carbonization; lithium-ion batteries; paper anode; super rate performance

The first use of nanocellulose extracted from bamboo fibers as a fibrous network skeleton and carbon dots derived from nanocellulose as guest fluorescent nanomaterials to construct a transparent, photoluminescent hybrid film is reported. The primary hydroxyls of nanocellulose are firstly converted to the carboxyl form by using tetramethyl-1-piperidinyloxy (TEMPO)-mediated oxidation to enhance the interfacial interaction with carbon dots and then to assemble heterogeneous network architectures through covalent bonding. The carbon dots derived from TEMPO-mediated oxidized nanocellulose display highly uniform spherical morphology with a narrow size distribution ranging from 6 nm to 11 nm. The resultant nanocellulose-based hybrid film has high transparency in bright field imaging and a strong blue luminescence under ultraviolet excitation. Furthermore, the biocompatible hybrid film extracted from the biomass exhibits excellent thermal stability and outstanding mechanical durability, which could be utilized as a substitute for petroleum-based film for diverse applications.

We designed an easy-to-fabricate multi-luminescent nanopaper with high transparency, for the first time, by grafting lanthanide complexes [Eu(dbm)3(H2O)2, Sm(dbm)3(H2O)2, Tb(tfacac)3(H2O)2] on TEMPO mediated oxidized nanofibrillated cellulose (ONFC). The lanthanide complex functionalized ONFC nanopaper (Ln–ONFC nanopaper, Ln = Eu, Sm, Tb) with uniform luminescence was rapidly fabricated after solvent exchange using a press-controlled extrusion papermaking method. The new TEMPO-induced carboxyl groups on the surface of ONFC provided the possibility to participate in the coordination with lanthanide ions and then to construct heterogeneous network architectures. The fluorescent properties of the Ln–ONFC hybrid nanopaper were significantly influenced by the amount of lanthanide complexes and the solvent medium during the extrusion. Based on simple manipulation and mild conditions, a highly transparent NFC template provided a soft matrix and afforded the high thermal stability and excellent luminescent properties of the Ln–ONFC nanopaper, which yields ever increasing potential to supersede petroleum-based materials for diverse applications.

Transparent, nanocellulose–ZnO (NC–ZnO) hybrid films were fabricated via a pressure controlled extrusion process using NC fibrils and sheet-like ZnO (s-ZnO) or belt-like ZnO (b-ZnO) nanostructures. The s-ZnO and b-ZnO conjoined with the NC fibrils to form a heterogeneous, fibrous network structure. The NC–ZnO hybrid films with different amounts of ZnO nanostructures showed a synergic feature of high optical transparency and excellent UV-blocking. The results indicated that NC assembled with s-ZnO hybrid film possessed excellent UV-blocking ability in a wide range from 200 to 375 nm, in contrast to NC–b-ZnO. Moreover, the prominent thermal and photo stability of transparent NC–ZnO hybrid films enhanced extensibility and ease of use for diverse biological applications, which require tolerance of temperature changes.

Carbon dots (CDs) have shown great promise in a wide range of bioapplications due to their tunable optical properties and noncytotoxicity. For the first time, a rational strategy was designed to construct new bio-nanoplatforms based on carboxylic acid terminated CDs (CDs-COOH) conjugating with amino terminated F-substituted nano-hydroxyapatite (NFAp) via EDC/NHS coupling chemistry. The monodisperse NFAp nanorods were functionalized with o-phosphoethanolamine (PEA) to provide them with amino groups and render them hydrophilic with respect to the ligand exchange process. The CDs-COOH@PEA-NFAp conjugates exhibits bright blue fluorescence under UV illumination, excellent photostability and colloidal stability. Due to their low cytotoxicity and good biocompatibility as determined by methyl thiazolyl tetrazolium (MTT) assay, the CDs-COOH@PEA-NFAp conjugates were successfully applied as bio-nanoplatforms to MCF-7 breast cancer cells for cellular imaging in vitro. More importantly, the functional CDs conjugated to NFAp provide an extended and general approach to construct different water-soluble NFAp bio-nanoplatforms for other easily functionalised luminescent materials. Therefore, these green nanoplatforms may be a prospective candidate for applications in bioimaging or targeted biological therapy and drug delivery.

A free-standing lithium titanate (Li4Ti5O12)/carbon nanotube/cellulose nanofiber hybrid network film is successfully assembled by using a pressure-controlled aqueous extrusion process, which is highly efficient and easily to scale up from the perspective of disposable and recyclable device production. This hybrid network film used as a lithium-ion battery (LIB) electrode has a dual-layer structure consisting of Li4Ti5O12/carbon nanotube/cellulose nanofiber composites (hereinafter referred to as LTO/CNT/CNF), and carbon nanotube/cellulose nanofiber composites (hereinafter referred to as CNT/CNF). In the heterogeneous fibrous network of the hybrid film, CNF serves simultaneously as building skeleton and a biosourced binder, which substitutes traditional toxic solvents and synthetic polymer binders. Of importance here is that the CNT/CNF layer is used as a lightweight current collector to replace traditional heavy metal foils, which therefore reduces the total mass of the electrode while keeping the same areal loading of active materials. The free-standing network film with high flexibility is easy to handle, and has extremely good conductivity, up to 15.0 S cm–1. The flexible paper-electrode for LIBs shows very good high rate cycling performance, and the specific charge/discharge capacity values are up to 142 mAh g–1 even at a current rate of 10 C. On the basis of the mild condition and fast assembly process, a CNF template fulfills multiple functions in the fabrication of paper-electrode for LIBs, which would offer an ever increasing potential for high energy density, low cost, and environmentally friendly flexible electronics.Keywords: cellulose nanofiber; flexible paper-electrode; free-standing fibrous network film; lithium-ion batteries; pressure-controlled extrusion process;

•A highly efficient approach for preparation of CNF from waste sackcloth.•H2O2/HNO3 solution was utilized as both bleaching agent and hydrolysis medium.•Sonication process was beneficial to form well dispersed colloidal suspensions.•CNF with 20–50 nm in width and hundreds of nanometers in length was obtained.A convenient and low cost process to prepare cellulose nanofibrils (CNF) from waste sackcloth by using H2O2/HNO3 solution as both bleaching agent and hydrolysis medium was recommended. The resultant CNF with high crystallinity was initially synthesized by the chemical disintegration process for the removal of non-cellulosic components and the crystallinity of CNF was 68.11% compared with that of sackcloth fibers (48.28%). The decomposition temperature of CNF was about 340 °C, which indicated that the thermal stability of the fibers was increased after the combined bleaching and hydrolysis. Subsequently, the homogenous CNF colloidal suspensions in water, ethanol and acetone were obtained after sonication treatment. The CNF in water suspensions with 20–50 nm in width and hundreds of nanometers in length was ultimately prepared under the conditions of different ultrasonic time.

Natural biomass based carbonaceous aerogels are becoming promising lightweight, biodegradable matrices to supersede traditional support materials in realizing future sustainable photochemistry and environmental protection. Herein, flower-like BiOBr loaded onto an ultralight TEMPO-mediated oxidized carbonaceous aerogel (BOB@OWMCA) support was successfully prepared using the edible winter melon as source material via a simple solvothermal method. The three-dimensional sponge-like OWMCA with surface functionalization displayed an ultralow density (17.7 mg cm−3) and large special surface area (30.6 m2 g−1). The BiOBr was homogeneously anchored on the surface of the hierarchical porous OWMCA and the material exhibited synergetic properties of the BiOBr photocatalyst and OWMCA support to strengthen its photodegradation capacity. The results indicated that the as-prepared BOB@OWMCA composite demonstrated an outstanding adsorption and photodegradation capacity for organic pollutants (rhodamine B) under visible light irradiation. Of importance here, the BOB@OWMCA composite showed a prominent advantage for easy collection and separation from the aqueous system, making it a promising candidate as a robust visible light responsive photocatalyst for a range of applications.

N-doped carbon dots were successfully synthesized via a one-step hydrothermal method by using edible winter melon as the source material. Mono-dispersed CDs 4.5–5.2 nm in diameter were achieved in a quantum yield (QY) of 7.51%. The photoluminescent CDs were demonstrated to be effective bio-imaging agents for hepG2 (liver hepatocellular carcinoma) cells.

•Calcium sulfate hemihydrate (CSH) whiskers were prepared via phase transition of CSD.•Uniform and regular morphology CSH whiskers with high aspect ratio were obtained.•Impurities in FGD gypsum were found to have little effect on whisker growth.•The results suggested a possible application for FGD gypsum.Calcium sulfate hemihydrate (CSH) whiskers were synthesized by phase transition in CaCl2 solution under atmospheric pressure. Analytical-grade calcium sulfate dihydrate (AR CSD) was used as the raw material for the synthesis of CSH whiskers, according to orthogonal experiments. The effects of reaction temperature, AR CSD content, H2SO4 content, and reaction time were investigated, and the crystallization conditions were optimized. The as-prepared CSH whiskers displayed a regular morphology and a highly uniform size, with an aspect ratio of 105. A simulation system was also established by blending various sulfates with AR CSD, to evaluate the effects of impurities in flue gas desulfurization (FGD) gypsum. The main aim was to prepare CSH whiskers directly from FGD gypsum, without any purification, using the optimized conditions. This is a facile potential alternative process for large-scale production of CSH whiskers using abundant FGD gypsum as source materials.

Highly flexible, transparent, and luminescent nanofibrillated cellulose (NFC) nanopaper with heterogeneous network, functionalized by rare-earth up-converting luminescent nanoparticles (UCNPs), was rapidly synthesized by using a moderate pressure extrusion paper–making process. NFC was successfully prepared from garlic skin using an efficient extraction approach combined with high frequency ultrasonication and high pressure homogenization after removing the noncellulosic components. An efficient epoxidation treatment was carried out to enhance the activity of the UCNPs (NaYF4:Yb,Er) with oleic acid ligand capped on the surface. The UCNPs after epoxidation then reacted with NFC in aqueous medium to form UCNP-grafted NFC nanocomposite (NFC–UCNP) suspensions at ambient temperature. Through the paper-making process, the assembled fluorescent NFC–UCNP hybrid nanopaper exhibits excellent properties, including high transparency, strong up−conversion luminescence, and good flexibility. The obtained hybrid nanopaper was characterized by transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscope (FE-SEM), up−conversion luminescence (UCL) spectrum, and ultraviolet and visible (UV–vis) spectrophotometer. The experimental results demonstrate that the UCNPs have been successfully grafted to the NFC matrix with heterogeneous network. And the superiorly optical transparent and luminescent properties of the nanopaper mainly depend on the ratio of UCNPs to NFC. Of importance here is that, NFC and UCNPs afford the nanopaper a prospective candidate for multimodal anti-counterfeiting, sensors, and ion probes applications.Keywords: extrusion; garlic skin; luminescent nanopaper; nanofibrillated cellulose; rare-earth up-converting nanoparticles

MoS2 nanolamellers were synthesized by a one-step oxidation–reduction reaction in solution, in which the (NH4)2MoS4 and H2C2O4·2H2O were used as reactants and then calcined at 800 °C under N2 for 1 h. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The diameter and nanoplate thickness of the obtained MoS2 nanolamellers were approximately 80 nm and 20–30 nm, respectively. These novel structures of nanolamellers had potential applications in solid lubricants.

•High-efficient transparent UV-blocking nanocellulose films were assembled.•Sheet-like, belt-like or particulate ZnO were used as UV-blocking agents.•Nanocellulose was extracted from bamboo fibers and oxidized by TEMPO.•CDs-ONC composites were synthesized using TTDDA as carbon source.•UV-blocking property was significantly enhanced with the addition of CDs.High-efficient transparent UV-blocking nanocellulose (NC) films were successfully assembled by pressured-extrusion of the composites of carbon dots (CDs), 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radical mediated oxidized nanocellulose (ONC) and ZnO nanostructures. ONC nanofibrils were firstly extracted from bamboo fibers and subsequently prepared by applying TEMPO oxidation. The as-obtained CDs-ONC-ZnO films exhibited high visible light transparency, excellent thermal stability and enhanced UV-blocking properties. Compared to the previously designed NC-ZnO films, CDs-ONC-ZnO films presented significant increase of UV-blocking ratio (UVR) with the same amounts of ZnO. Moreover, the UVR of CDs-ONC-s-ZnO film with 4 wt% sheet-like ZnO (s-ZnO) at 300 nm and 225 nm is 92.74% and 98.99%, better than the same condition of CDs-ONC-b-ZnO film added with belt-like ZnO (b-ZnO) and CDs-ONC-p-ZnO film added with commercial particulate ZnO (p-ZnO). An interesting discovery is that when adding 4 wt% p-ZnO, the UVR of CDs-ONC-p-ZnO film is very close to the value of NC-s-ZnO film with the same amount of s-ZnO.

Transparent, nanocellulose–ZnO (NC–ZnO) hybrid films were fabricated via a pressure controlled extrusion process using NC fibrils and sheet-like ZnO (s-ZnO) or belt-like ZnO (b-ZnO) nanostructures. The s-ZnO and b-ZnO conjoined with the NC fibrils to form a heterogeneous, fibrous network structure. The NC–ZnO hybrid films with different amounts of ZnO nanostructures showed a synergic feature of high optical transparency and excellent UV-blocking. The results indicated that NC assembled with s-ZnO hybrid film possessed excellent UV-blocking ability in a wide range from 200 to 375 nm, in contrast to NC–b-ZnO. Moreover, the prominent thermal and photo stability of transparent NC–ZnO hybrid films enhanced extensibility and ease of use for diverse biological applications, which require tolerance of temperature changes.

High performance transparent conductive cellulose-based nanopaper (TCCNP) with long-term durability is a predominant alternative for the upscale production of next-generation green flexible electronics. Here, dual-layered TCCNP with excellent mechanical robustness and chemical stability was successfully assembled by tight binding between the mussel-inspired polydopamine functionalized nanofibrillated cellulose (PDA@NFC) substrate and the silver nanowire (AgNW) layer. The highly adhesive PDA coatings on the NFC surface uniformly connected AgNW networks and simultaneously soldered the wire-to-wire junctions, thus dramatically increasing the overall electrical conductivity. The as-prepared TCCNP possesses exceptional optoelectronic properties with an optical transmittance of 90.93% at a wavelength of 550 nm and a sheet resistance of 14.2 Ω sq−1. Meanwhile, the TCCNP displays excellent mechanical stability with negligible changes in optoelectronic performances even after 1000 bending cycles and 100 peeling tests. Furthermore, the TCCNP exhibits outstanding air and chemical corrosion stabilities after being exposed to air for 150 days or immersed in different solutions for 180 min, and its transparent conductive performance remains constant close to its initial values, which is superior to those of NFC–AgNW TCCNP without PDA or the commercial ITO/PET transparent conductive films (TCFs). More importantly, the ease of disposal of TCCNP and its good stability can greatly contribute to its application in multifunctional electronic and photoelectric flexible devices.

We designed an easy-to-fabricate multi-luminescent nanopaper with high transparency, for the first time, by grafting lanthanide complexes [Eu(dbm)3(H2O)2, Sm(dbm)3(H2O)2, Tb(tfacac)3(H2O)2] on TEMPO mediated oxidized nanofibrillated cellulose (ONFC). The lanthanide complex functionalized ONFC nanopaper (Ln–ONFC nanopaper, Ln = Eu, Sm, Tb) with uniform luminescence was rapidly fabricated after solvent exchange using a press-controlled extrusion papermaking method. The new TEMPO-induced carboxyl groups on the surface of ONFC provided the possibility to participate in the coordination with lanthanide ions and then to construct heterogeneous network architectures. The fluorescent properties of the Ln–ONFC hybrid nanopaper were significantly influenced by the amount of lanthanide complexes and the solvent medium during the extrusion. Based on simple manipulation and mild conditions, a highly transparent NFC template provided a soft matrix and afforded the high thermal stability and excellent luminescent properties of the Ln–ONFC nanopaper, which yields ever increasing potential to supersede petroleum-based materials for diverse applications.

Natural biomass based carbonaceous aerogels are becoming promising lightweight, biodegradable matrices to supersede traditional support materials in realizing future sustainable photochemistry and environmental protection. Herein, flower-like BiOBr loaded onto an ultralight TEMPO-mediated oxidized carbonaceous aerogel (BOB@OWMCA) support was successfully prepared using the edible winter melon as source material via a simple solvothermal method. The three-dimensional sponge-like OWMCA with surface functionalization displayed an ultralow density (17.7 mg cm−3) and large special surface area (30.6 m2 g−1). The BiOBr was homogeneously anchored on the surface of the hierarchical porous OWMCA and the material exhibited synergetic properties of the BiOBr photocatalyst and OWMCA support to strengthen its photodegradation capacity. The results indicated that the as-prepared BOB@OWMCA composite demonstrated an outstanding adsorption and photodegradation capacity for organic pollutants (rhodamine B) under visible light irradiation. Of importance here, the BOB@OWMCA composite showed a prominent advantage for easy collection and separation from the aqueous system, making it a promising candidate as a robust visible light responsive photocatalyst for a range of applications.