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A facile and feasible method for decoration of iron oxide (Fe3O4) submicron-sized particles on carbon paper at room temperature in a short time of 10 min is demonstrated in this work. The Fe3O4-particles decorated carbon papers were used as the negative electrode for an Fe-air rechargeable battery in both an alkaline aqueous solution system and an all-solid-state system. As for the all-solid-state Fe-air rechargeable battery, KOH-ZrO2 electrolyte powder developed by our group was used in the battery fabrication. In the alkaline aqueous solution based Fe-air rechargeable battery, a high initial discharge capacity of 460 mAh g−1(Fe) was achieved. Meanwhile, in the novel all-solid-state Fe-air rechargeable battery system, an initial discharge capacity of 70 mAh g−1(Fe) was obtained demonstrating the feasibility of this system that could be further developed towards a practical Fe-air rechargeable battery for portable and lightweight device application.

Here we report the construction of CoFe2O4 coating on carbon fiber and the coated paper was used as the interlayer between the separator and cathode of Li-S batteries. The amorphous CoFe2O4 coating was deposited by the industry-oriented spray pyrolysis technique and carbon fiber was completely enwrapped by the coating. Compared to the non-coated carbon fiber, the coated carbon fiber as the interlayer exhibits a superior reversible capacity of 1086 mA h g−1 at moderate current of 0.1C and a low decay rate in the capacity of 0.043% per cycle after 1000 cycles at 1C. Excellent long-term cycling life and rate capacity were also achieved through the coated interlayer. The specially designed interlayer showed remarkable capability to trap effectively the intermediate LPS (lithium polysulfide). The significantly inhibited “shuttle effect” of LPS would give insight into designing and making the interlayer by using new coating materials for enhanced performances of the Li-S batteries.

paper-like films of reduced graphene oxide with controllable shapes and thickness were prepared via funnel filtration and thermal reduction of graphene oxide (GO), which could work as flexible surface-enhanced Raman scattering (SERS) substrates to detect Rhodamine 6G (R6G) molecules. The SERS signal intensity of R6G on annealed films was found to be related with the annealling temperature. The most intense signal was observed for the film obtained at 800 °C. While for the sample annealed at 1000 °C, no SERS signal could be detected. The underlying mechanism for the difference was discussed. The reported preparation process of flexible rGO paper is simple and cost-effective, which shows great potential in rapid biochemical analysis of agricultural products with irregular surfaces.

Nanoparticles are used in several applications due to the unique properties they possess compared to bulk materials. Production techniques have continuously evolved over the years. Recently, there has been emphasis on environmentally friendly manufacturing processes. Substrate properties often limit the possible production techniques and, for example; until recently, it has been difficult to incorporate nanoparticles into paper. Chemical reduction of a precursor in the presence of paper changes the bulk properties of paper, which may limit intended end-use. In this study, we present a novel technique for incorporating silver nanoparticles into paper surface using a flame pyrolysis procedure known as Liquid Flame Spray. Papers precoated with mineral pigments and plastic are used as substrates. Silver nanoparticles were analyzed using SEM and XPS measurements. Results show a homogeneous monolayer of silver nanoparticles on the surface of paper, which demonstrated antibacterial properties against E. coli . Paper precoated with plastic showed more nanoparticles on the surface compared to pigment coated paper samples except for polyethylene-precoated paper. The results demonstrate a dry synthesis approach for depositing silver nanoparticles directly onto paper surface in a process which produces no effluents. The production technique used herein is up scalable for industrial production of antibacterial paper.

As a typical membrane matrix with attractive flexibility, paper has exhibited great feasibility to serve as surface-enhanced Raman scattering (SERS) substrate in the environmental monitoring and surveillance. In this research, we have designed and fabricated a distinctive hydrophilic-hydrophobic SERS substrate utilizing several ordinary papers loaded with Ag nanowires (Ag NWs). Remarkable SERS activities with an enhancement factor (EF) up to 2.63 × 106 was successfully achieved in the assembly Ag NWs with the optimal amount of nanotips and overlaps. The hydrophilic-hydrophobic strategy could contribute to anchoring microdroplets and thus enrich analytes to improve the homogeneity of substrate with a low relative standard deviation of 10.6%. Furthermore, the sophisticated SERS substrate was also applied in the in-situ detection of trace furazolidone on fish under the interference of malachite green and the reliable recovery rates were demonstrated as well.

We presented a three-step method for the preparation of superhydrophobic cellulose filter paper. It involved ZnCl2 pre-treatment to activate the cellulose fibers, a SiO2 sol-gel process to increase surface roughness and grafting of hexadecyl trimethoxysilane groups to chemically enhance the water repellency. The water contact angle of the modified paper reached 154.8°. XRD analysis confirmed silica as the product from the sol-gel process. EDS and SEM analysis showed that pre-treatment results in greater silica adhesion and retention on the paper surface. The modified paper proved to be self-cleaning and resistant to staining. Further tests under various conditions showed that ZnCl2 pre-treatment improved the durability of the superhydrophobic paper. It was concluded that pre-treatment of the filter paper prior to superhydrophobic coating results in a disruption in the cellulose crystalline structure that favours greater silica adhesion and retention.

In this work, a facile method was developed to prepare reactive superhydrophobic paper by the attachment of 10-undecylenoyl chloride onto homogenized α-cellulose followed by one-step spray-coating of the resulting cellulose derivative (α-cellulose 10-undecylenoyl ester, CUE) onto filter paper. By spray-coating a CUE suspension with a concentration of 1.04 wt% for at least 6 mL, the paper surface became superhydrophobic, which had a water contact angle of 152 ± 2° with the advancing and receding angles of 165 ± 2° and 144 ± 2° and the slide angle of 6°. Additionally, the resulting surface showed a good durable stability, acid-base stability and thermal stability. More interestingly, an obvious photoclick thiol-ene reaction could be conducted on such superhydrophobic paper, which would further enlarge the application fields of superhydrophobic surfaces.

In the current efficient energy focused society, metal–air batteries (MAB), which have high theoretical energy densities in comparison with other batteries have attracted tremendous attention for electronics and electric vehicle applications. Efficient utilization of the active material in the negative electrode with oxygen from air as the positive electrode could enable the development of a lightweight and portable metal-air battery with large energy density. Zinc (Zn), which is an abundant and inexpensive material that exhibits small voltage fluctuation during discharge as well as large discharge capacity in a liquid electrolyte-based battery system, is a good candidate as the active material in a MAB. Therefore, in this work, a Zn-air battery is fabricated and characterized using electroplated metallic Zn on carbon paper in order to increase the working contact area between Zn and the carbon paper which serves as the current collector. A near theoretical discharge capacity of 814 mAh g−1 (Zn) was achieved in an aqueous KOH liquid electrolyte system. Meanwhile, an all-solid-state Zn-air battery using a sol-gel-derived KOH-ZrO2 solid electrolyte was also fabricated which demonstrated an initial discharge capacity of 30 mAh g−1 (Zn).

Ag triangular nanoplates have been widely used as the SERS substrate due to their anisotropic morphology and sharp corners. In this work, SERS activity of Ag triangular nanoplates on glass and paper substrates was investigated with different concentration and size. A tiny triangular nuclei based synthesis method was employed to produce Ag triangular nanoplates with different size. And the extinction coefficients of Ag triangular nanoplates with different size were quantified by inductively coupled plasma mass spectrometry (ICP-MS) and transmission electron microscopy (TEM). With definite concentration, Ag triangular nanoplates with small size showed stronger SERS intensity on glass substrate at high concentrations, while large Ag triangular nanoplates exhibited better SERS effect on paper substrate at low concentrations. The possible reasons for distinct SERS activity of Ag triangular nanoplates on glass and paper were discussed with scanning electron microscope (SEM) characterization. These results exhibited important implications for fabricating Raman substrates using Ag triangular nanoplates and could be applied to the SERS sensing with flexile substrate.

Here, a novel, simple, cost-effective, environment-friendly, non-invasive and mediator free, reduced graphene oxide (RGO) modified paper-based biosensing platform was reported. A conductive platform was generated over the ivory paper sheet via in-situ reduction of graphene oxide. The conductivity of the RGO paper was found as 0.86 S cm−1. This substrate was used for deposition of cysteine capped gold nanoparticles (Cys-AuNPs) using electrophoretic deposition technique at 60 V for biosensing application. Scanning electron microscopic images show the deposition of Cys-AuNPs in the spherical bunch on the RGO paper. The Cys-AuNPs deposition on RGO paper was confirmed by energy-dispersive x-ray spectroscopy and X-ray photoelectron spectroscopy and used for immobilization of monoclonal antibodies. This paper-based immunosensor based on chronoamperometry technique has the ability of direct electron transfer without using any mediator. This platform can replace commercially available electrodes [Indium Tin Oxide (ITO) and fluorine-doped tin oxide (FTO)] coated glass substrate, glassy carbon and gold] for electronic and electrochemical applications including point-of-care (POC) devices.

Owing to the high specific surface area and easy accessability to targeting biomolecules, emerging non-noble-metal networks are developed as an ultra-active catalyst for molecular detection. In this work, a facile flexible enzyme-free glucose sensor with superior sensing performance has been successfully constructed by integrating laser-scribed carbon paper (LSCP) with copper network (CN). Remarkably, operation parameters are modeled and optimized by Central Composite Design (CCD) to obtain an optimal conductivity of 4.783 × 107 S·m−1 for CN. Due to the great electronic/ionic pathway between LSCP of ample active sites and CN of excellent conductivity, the disposable biosensor exhibits fast electron transfer kinetics. For glucose detection, LSCP/CN exhibits an excellent sensitivity of 3626.6 μA mM−1 cm−2, a wide linear range from 1 μM to 7.96 mM, an ultra-low detection limit of 30 nM (S/N = 3) as well as favorable reusability. Satisfactory anti-interference capacity to electro-active oxides and selectivity against carbohydrates studied for concentrations up to normal physiologic levels and higher concentrations are systematically investigated. The applications of glucose determination in human serum and perspiration samples are also successful, with recoveries of 100.8% (± 2.28%) and 92.1% (±3.61%), respectively. Experimentally, the current response of the LSCP/CN biosensor is resilient to mechanical deformation with less than 8% decay even after 1000 cycles of 1 mm repeated bending and 180° cyclical folding tests. As such, LSCP/CN can be applicable for flexible, attachable and potentially wearable biosensors to attain real-time physiological monitoring.

Hydrophobic paper decorated Ag nanoparticles (NPs) with a uniform distribution was fabricated in an oil-paper-aqueous triphasic system via a facile in situ interfacial reduction approach. Interestingly, the Ag NPs formed at the paper/aqueous interface could migrate to the oil/paper interface. Moreover, these Ag NPs would not continue to migrate away the paper surface into the oil phase but was completely confined in the solid paper matrix. This phase confinement of migrated Ag NPs in the paper matrix creates abundant 3D hot spots for plasmonic enhancement. The obtained Ag-loaded paper exhibits an excellent SERS activity, reliable reproducibility and autofluorescence suppression effect, which enabling it as a promising platform for qualitative and quantitative SERS study. Due to its condensation effect, the hydrophobic paper surface can be used as a concentrator to enrich water-soluble analytes over the SERS active domains for highly sensitive detection (10−9 mol/L−1). Furthermore, the Ag-loaded paper combined with the feature of chromatography and plamon-enhanced optical signals possesses ability to perform synchronous separation and surface-enhanced Raman scattering (SERS) detection of complex samples.

Lithium-sulfur (Li-S) batteries have remarkably high theoretical specific capacity as promising candidates for next-generation energy storage. However, the “polysulfides shuttle” effect hampers its commercial application. Here, we use a kind of rice paper as a raw material to get inorganic oxides doping carbon felt by the facile carbonization method, and then modified by a simple coating process using poly (fluorenyl ether ketone) and Super P slurry. The special structure of the carbon felt derived from rice paper and its modified layer endow the final electronic conductive interlayer with inherent polysulfides absorbents and ion Coulombic repulsion functions, respectively, which show synergistic effect for trapping polysulfides. As an interlayer of Li-S batteries, the obtained carbon felt/poly (fluorenyl ether ketone)& Super P (CFSS) interlayer shows excellent electrochemical performance in improving specific capacity and decreasing polarization. The batteries with CFSS interlayer exhibit a high capacity of 837 mA h g−1 at 2.0 C and a high initial capacity of 1073.4 mA h g−1 and good capacity retention of 824.5 mA h g−1 after 500 cycles at 0.5 C. CFSS interlayer also shows excellent anti-self-discharge performance. Therefore, the simple and economical CFSS interlayer can be considered as a promising component for high performance Li-S batteries.

Mechanically robust graphene papers with both high gravimetric and volumetric capacitances are desired for high-performance energy storages. However, it’s still a challenge to tailor the structure of graphene papers in order to meet this requirement. In this work, a kind of chemical-reduction-tailored mechanically-robust reduced graphene oxide/carbon nanotube hybrid paper has been reported for high-performance electrochemical capacitive energy storages. Gallic acid (GA), as an excellent reducing agent, was used to reduce graphene oxide. Through vacuum filtration of gallic acid reduced graphene oxide (GA-rGO) and carboxylic multiwalled carbon nanotubes (MWCNTs) aqueous suspensions, mechanically robust GA-rGO/MWCNTs hybrid papers were obtained. The resultant hybrid papers showed high gravimetric capacitance of 337.6 F g−1 (0.5 A g−1) and volumetric capacitance of 151.2 F cm−3 (0.25 A cm−3). In addition, the assembled symmetric device based on the hybrid papers exhibited high gravimetric capacitance of 291.6 F g−1 (0.5 A g−1) and volumetric capacitance of 136.6 F cm−3 (0.25 A cm−3). Meanwhile, it exhibited excellent rate capability and cycling stability. Above all, this chemical reduction tailoring technique and the resultant high-performance GA-rGO/MWCNTs hybrid papers give an insight for designing high-performance electrodes and hold a great potential in the field of energy storages.

Tin-based compounds are potential anode materials for high performance lithium-ion batteries (LIBs). Due to the low melting point of metallic Sn, it is hard to maintain the crystal morphology of Sn during the as-follow process of carbon coating for high performance anode. In this work, the core@shell composite of SnOx@carbon (SnOx@C) is successfully fabricated on the substrate of carbon paper (CP) through electrodeposition and carbonization based on the precursor of Sn nanoparticles. A passivation shell is essentially grown onto Sn particles to obtain a stable structure of SnOx@C, otherwise the Sn particles will be pulverized and fell off the substrate of CP during the subsequent process of carbonization. The as-produced CP/SnOx@C film has excellent flexibility and mechanical stability to be directly served as electrode for LIBs. Carbon shell prevents the detachment and agglomeration of the active particles during lithiation/delithiation processes and maintains the stability of the conductive network. After 100th cycles, CP/SnOx@C electrode delivers 0.8 mAh cm−2, much higher than the capacity 0.37 mAh cm−2 of CP/Sn electrode operated at the current density of 0.1 mA cm−2. These features enable the flexible film of CP/SnOx@C to be attractive applications in energy storage devices.

Novel sensors based on fluorescent carbon dots were developed for a rapid, selective, and sensitive detection of pyrimethanil, a fungicide widely used in many agricultural crops. The carbon dots were synthesized from maleic anhydride and triethylenetetramine via a facile one-pot pyrolysis. A quenched fluorescence intensity of carbon dots in the presence of pyrimethanil occurred via inner filter effect and strong π-π interaction. The carbon dots were sensitive to pyrimethanil across a linear range from 0.5 to 75 µM with a low detection limit of 14 nM. The sensing results could be generated in 30 s. The fluorescent carbon dots showed excellent stability and selectivity to pyrimethanil in the presence of interferences, including fungicides and metal ions. They were also successfully employed for pyrimethanil detection in apples, cucumbers, and drinking water, yielding 98.6–107.1% recovery. The practical, portable, and reusable paper-based sensor was also developed. The cytotoxicity of carbon dots was tested to demonstrate that they are sufficiently safe to use. The novel pyrimethanil sensor based on fluorescent carbon dots developed in this work can be used as a high-performance sensor and a rapid tool for quality control in food, agricultural, and environmental monitoring.

Superhydrophobic paper with remarkable durability is of considerable interest for its practical applications. In this study, a scalable, inexpensive, and universal surface sizing technique was implemented to prepare superhydrophobic paper with enhanced durability. A thin layer of starch-based composite, acting as a bio-binder, was first coated onto the paper surface by a sophisticated manufacturing technique called surface sizing, immediately followed by a spray coating of hexamethyl disilazane treated silica nanoparticles (HMDS-SiNPs) dispersed in ethanol on the surface of the wet starch-coated sheet, and the dual layers dried at the same time. Consequently, durable superhydrophobic paper with bi-layer structure was obtained after air drying. The as-prepared superhydrophobic paper not only exhibited a self-cleaning behavior, but also presented an enhanced durability against scratching, bending/deformation, as well as moisture. The universal surface sizing of starch-based composites may pave the way for the up-scaled and cost-effective production of durable superhydrophobic paper.

Paper-based surface-enhanced Raman scattering (SERS) substrates receive a great deal of attention due to low cost and high flexibility. Herein, we developed an efficient SERS substrate by gravure printing of sulfonated reduced graphene-oxide (S-RGO) thin film and inkjet printing of silver nanoparticles (AgNPs) on weighing paper successively. Malachite green (MG) and rhodamine 6G (R6G) were chosen as probe molecules to evaluate the enhanced performance of the fabricated SERS-active substrates. It was found that the S-RGO/AgNPs composite structure possessed higher enhancement ability than the pure AgNPs. The Raman enhancement factor of S-RGO/AgNPs was calculated to be as large as 109. The minimum detection limit for MG and R6G was down to 10−7 M with good linear responses (R2 = 0.9996, 0.9983) range from 10−4 M to 10−7 M. In addition, the S-RGO/AgNPs exhibited good uniformity with a relative standard deviation (RSD) of 7.90% measured by 572 points, excellent reproducibility with RSD smaller than 3.36%, and long-term stability with RSD less than 7.19%.

Designing highly efficient electrocatalysts for oxygen evolution reaction is important to meet the requirement of various renewable energy storage and conversion devices. Generally, the performance of OER catalysts can be significantly improved by synergistic action of the underlying conductive substrate. In this work, a commercial graphite paper was used as a facile substrate with catalytic activity. Graphite paper produced 10 mA cm −2 at an overpotential of 447 mV with a Tafel slope of 62 mV dec −1 . By depositing NiFe hydroxide or Mn oxide film onto the graphite paper, the electrode presented a superior activity for water oxidation, which was believed to be synergistically contributed by their available electrochemically active sites associated with the deposited film and the active substrate. High activities were also accompanied by remarkable durability at large current density levels. Our results illustrated a guideline to the design of inexpensive and highly active composite electrode for water oxidation.

Superhydrophobic coatings on paper were achieved by means of incorporating micro-nano hierarchical topography, where the water droplet was repelled and rested in a spherical shape. A silica sol, which was prepared using tetraethylorthosilicate (TEOS) as precursor and trimethylethoxysilane (TMES) as co-precursor, was poured on the paper to form a superhydrophobic surface. The coating was fluorine-free, environmentally friend, and could be easily fabricated on different kinds of papers. Besides, the transmittance of prepared coating reached up to 92% in visible light range, and the words on treated paper showed a good visualization. Moreover, the treated paper showed superior mechanical durability against 100 times of deformation, remarkable stability towards both the acidic and basic solutions. The treated paper could withstand 70 cycles of water condensation test (from 60 °C, 90% relative humidity to 10 °C) without losing superhydrophobicity, suggesting a long-term protection for paper.

Graphene-based all-solid-state supercapacitors (ASSSCs) have received increasing attention. It’s a great challenge to fabricate high-performance flexible solid-state supercapacitors with high areal and volumetric energy storage capability, superior electron and ion conductivity, robust mechanical flexibility, as well as long term stability. Herein, we report a facile method to fabricate flexible ASSSCs based on densely-packed reduced graphene oxide (rGO)/polypyrrole nanoparticle (PPy NP) hybrid papers with a sandwich framework, which consists of well-separated and continuously-aligned rGO sheets. The incorporation of PPy NPs not only provides pseudocapacitance but also facilitates the infiltration of gel electrolyte. The assembled ASSSCs possess maximum areal and volumetric specific capacitances of 477 mF/cm 2 and 94.9 F/cm 3 at 0.5 mA/cm 2 . They also exhibit little capacitance deviation under different bending states, excellent cycling stability, small leakage current and low self-discharge characteristics. Additionally, the maximum areal and volumetric energy densities of 132.5 μWh/cm 2 and 26.4 mWh/cm 3 are achieved, which indicate that this hybrid paper is a promising candidate for high-performance flexible energy storage devices.

The study reports on the preparation of polyacrylonitrile fiber paper (PANFP) functionalized with polydopamine (PD) and silver nanoparticles (Ag NPs), named as Ag NPs/PD/PANFP. The composite material was obtained via a simple two-step chemical process. First, a thin polydopamine layer was coated onto the PANFP surface through immersion into an alkaline dopamine (pH 8.5) aqueous solution at room temperature. The reductive properties of polydopamine were further exploited for the deposition of Ag NPs. The morphology and chemical composition of the composite material were characterized using scanning electron microscopy (SEM), X-ray diffraction pattern (XRD) and X-ray photoelectron spectroscopy (XPS). The catalytic activity of the nanocomposite was evaluated for the reduction of 4-nitrophenol using sodium borohydride (NaBH 4 ) at room temperature. The Ag NPs/PD/PANFP displayed good catalytic performance with a full reduction of 4-nitrophenol into the corresponding 4-aminophenol within 30 min. Moreover, the composite material exhibited a good stability up to 4 cycles without a significant loss of its catalytic activity.

A controlled monolayer-by-monolayer deposition process has been developed to fabricate Pt coating on carbon fiber paper with complex network structures using a dual buffer (Au/Ni) strategy. The X-ray diffraction, electrochemical quartz crystal microbalance, current density analyses, and X-ray photoelectron spectroscopy results conclude that the monolayer deposition process accomplishes full coverage on the substrate and that the thickness of the deposition layer can be controlled on a single atom scale. This development may pave a way to fabricate superior Pt catalysts with the minimal Pt usage. In fact, the present Pt group metal loading is 25 times lower than the U.S. DOE 2017 target value. (C) 2017 Elsevier B.V. All rights reserved.

Herein, we proposed a facile strategy for preparing well-distributed Sb-doped SnO2 nanoparticles on carbon paper (CP) via electrodeposition and in-situ oxidation as bifunctional electrodes for vanadium redox flow batteries. SnO2 and Sb-doped SnO2 modified carbon paper (CP-SnO2 and CP-SnO2/Sb) was respectively obtained by electrodepositing metals (Sn and Sn/Sb) nanoparticles, followed by a conversion to metal oxides with in-situ oxidation. CP-SnO2 exhibited better electrochemical performance toward V3+/V2+ and VO2+/VO2+ redox reactions than CP. This is because SnO2 increases active sites and hydrophilicity, which accelerates electrochemical kinetic and mass transfer for vanadium redox reactions. CP-SnO2/Sb had better electrochemical activity than CP-SnO2, because smaller Sb-doped SnO2 nanoparticles more effectively disperse through carbon fibers, producing more active sites. Furthermore, Sb doping improved conductivity of SnO2. Briefly, CP-SnO2/Sb exhibited excellent hydrophilicity, abundant active sites, and good conductivity, resulting in superior electrochemical activity. We next employed CP-SnO2/Sb as bifunctional electrodes in cell. The cell using CP-SnO2/Sb had better cycling stability and more capacity retention during a 50-cycle charge–discharge test at 50 mA cm−2. CP-SnO2/Sb reduced the electrochemical polarization of cell at higher current density. Overall, the cell using CP-SnO2/Sb showed a 9% increase in energy efficiency compared to pristine cell (64.5%) at 150 mA cm−2.

Graphene-based all-solid-state supercapacitors (ASSSCs) are one of the most ideal candidates for high-performance flexible power sources. The achievement of high volumetric energy density is highly desired for practical application of this type of ASSSCs. Here, we present a facile method to boost volumetric performances of graphene-based flexible ASSSCs through incorporation of ultrafine polyaniline-poly(4-styrenesulfonate) (PANI-PSS) nanoparticles in reduced graphene oxide (rGO) papers. A compact structure is obtained via intimate contact and π–π interaction between PANI-PSS nanoparticles and rGO sheets. The hybrid paper electrode with the film thickness of 13.5 μm, shows an extremely high volumetric specific capacitance of 272 F/cm3 (0.37 A/cm3 in a three-electrode cell). The assembled ASSSCs show a large volumetric specific capacitance of 217 F/cm3 (0.37 A/cm3 in a two-electrode cell), high volumetric energy and power density, excellent capacitance stability, small leakage current as well as low self-discharge characteristics, revealing the usefulness of this robust hybrid paper for high-performance flexible energy storage devices.

In this study, we report the simple fabrication of an active substrate assisted by gold nanostructures (AuNS) for application in surface-enhanced Raman scattering (SERS) using copier paper, which is a biodegradable and cost-effective material. As cellulose is the main component of paper, it can behave as a reducing agent and as a capping molecule for the synthesis of AuNS on the paper substrate. AuNS can be directly generated on the surface of the copier paper by addition of halides. The AuNS thus synthesized were characterized by ultraviolet–visible spectroscopy, SEM, XRD, and XPS. In addition, the SERS effect of the AuNS–paper substrates synthesized by using various halides was investigated by using rhodamine 6G and melamine as probe molecules.

In this work, a novel polymeric fluorescent brightener based on coumarin (PFBC) was synthesized, using three-step synthetic route, from 7-amino-4-methylcoumarin, coumarin monomer (FBC), Acrylamide (AM) and methacrylatoethyl trimethyl ammonium chloride (DMC). The structure of PFBC was characterized by FT-IR, 1HNMR and GPC. PFBC was applied to paper fiber as light stabilizer, fluorescent brightener and surface sizing agent and its performances were evaluated by measuring the UV–vis, fluorescence, thermal stability, the cationic degree, surface strength and smoothness of paper, the brightness degree of paper and the PC value of paper. Results showed that PFBC had better solubility in water than that of FBC, by measuring the optical properties. Through the surface sizing experiment and UV aging experiment, PFBC not only enhanced the surface strength and smoothness of paper as a surface sizing agent, but also had better effect on anti-UV aging than that of FBC as light stabilizer and fluorescent brightener.

The integration of flexible electronic sensors in clinical diagnostics is visioned to significantly reduce the cost of many diagnostic tests and ultimately make healthcare more accessible. This study concentrates on the characterisation of inkjet-printed bio-functionalised polythiophene films on paper-based ultrathin gold film (UTGF) electrodes and their possible application as biorecognition layers. Physicochemical surface properties (topography, chemistry, and wetting) and electrochemical characteristics of water-soluble regioirregular tetraethylene-glycol polythiophene (TEGPT) and biotin-functionalised TEGPT (b-TEGPT) films were examined and compared. In addition, their specificity towards streptavidin protein was tested. The results show that stable supramolecular biorecognition layers of insulating b-TEGPT and streptavidin were successfully fabricated on a paper-based UTGF by inkjet-printing. Good adhesion of thiophene to UTGF can be attributed to covalent linkage between sulphur and gold, whereas the stability of the streptavidin layer is due to the high affinity between biotin and streptavidin. The device introduced can be utilised in the development of biosensors for clinically relevant analytes e.g. for detecting complementary DNA oligomers or antibody–antigen complexes.

Lithium-sulfur (Li-S) battery is next generation battery technology but it’s commercialization is obstructed primarily due to the shuttling effect of lithium polysulfides (LiPSs). Herein, we report an effective approach using pencil coated pyrolyzed cellulose filter paper as an interlayer to suppress the LiPSs dissolution into the electrolyte and thus allowing effective utilization of active sulfur cathode. Here, the binder clay particles (mainly SiO2) of pencil graphite facilitate the adsorption of LiPSs, whereas graphite increases the electrical conductivity and acts as a physical barrier to LiPSs. To investigate further, we utilize three different grades of pencil (4B, HB, 5H) which vary in terms of clay (SiO2) composition. It is observed that the HB pencil coated interlayer has the right balance of silica and graphite, which results in an impressive initial capacity of 1352 and 995 mAh g−1 at the current density of 0.1 and 0.5 A g−1, respectively. The cell exhibit high cycling stability of 900 mAh g−1 at 1 A g−1 (3.0 C) for 350 cycles with a slow capacity decay of 0.07% per cycle. The phenomenon of LiPSs adsorption is further understood using post-cycling analysis, H-cell adsorption testing, and shuttle factor calculation for the development of commercial Li-S batteries.

How to function properly under extreme working conditions is a key challenge for flexible electronic devices because their performance is often susceptible to environmental conditions. Herein, we demonstrated the fabrication, evaluation, and application of a flexible and highly conductive meta-aramid fiber paper (MAFP) by combining oxygen plasma treatment and electroless silver plating. The plasma treatment etched the MAFP surface and introduced large amounts of oxygen-containing groups which led to the formation of continuous silver coating and high interface binding between MAFP and Ag nanoparticles. The results showed that the silver-coated MAFP had an electrical resistance as low as 0.152 Ω/sq and exhibited excellent temperature, mechanical and chemical stability. Finally, these properties of silver-coated MAFP were exploited for its use as electromagnetic interference (EMI) shielding. Experimental results revealed that the EMI shielding effectiveness (SE) of the silver-coated MAFP reached as high as 95.47 dB and a specific EMI SE of 530.38 dB·mm−1. These results have clearly demonstrated that MAFP can become highly electrically conductive after simple plasma treatment and silver coating while keeping its excellent thermal and chemical stability and therefore holds great promise for the development of new kinds of all-weather flexible electronic devices.

Metal-organic frameworks (MOFs) are considered as a promising energy storage material owing to their inherent advantages of large surface area, regulatable pore size and functional groups. However, the relative poor electronic conductivity is an obstacle to their wide practical application. Herein, the partially-exfoliated graphite paper (EGP) composed of graphene nanosheets is prepared by a controlled cathodic exfoliation. EGP exhibits 3D hierarchical porous structure and good electronic conductivity, which acts as an ideal substrate for growing accordion-like structure NiCo-based bimetal-organic framework (NCMOF). The as-synthesized NCMOF/EGP shows high areal specific capacitance of 2.41 F cm−2 at 0.5 mA cm−2, and good rate performance of 72.6% at the current densities from 0.5 to 20 mA cm−2. Furthermore, the constructed NCMOF/EGP//active carbon delivers an energy density of 0.11 mW h cm−2 at a power density of 0.75 mW cm−2, and long cycle life. The outstanding electrochemical energy storage performance of NCMOF/EGP are assigned to 3D hierarchical porous structure and good electronic conductivity of EGP combined with layered structure of NCMOF.

The portable, low-cost and sensitive biosensors are essential for in vitro diagnostics. Here, with a highly porous poly( l -lactic) acid nanofiber membrane (p-PLLA), an efficient and sensitive bioassay is created for biomarker detection, giving out colorimetric and fluorescence dual signals. A sensitivity-enhancing strategy is achieved based on the high porosity, loading capacity of p-PLLA and gold nanoparticles-based signal amplification. Through a sandwich immunoreaction strategy, the gold nanoparticle-labeled detector antibodies accumulate on the p-PLLA membrane and show a naked-eye-readable red spot starting from a cut-off value of the target biomarker. After adding goat anti-mouse IgG/FITC antibody (IgG-FITC), which is bound to the detector antibody, the concentration of the target biomarker can be accurately calculated by the differences in fluorescence intensity of IgG-FITC solution before and after the immunoreaction. When the liver cancer marker (α-fetoprotein) is used as a model analyte, this bioassay performs with excellent convenience and a high level of sensitivity. The preset visual color mutation point is 10 ng mL−1 (cut-off value) and the limit of detection is 0.17 pg mL−1. It shows good prospects of screening cancer biomarkers and point-of-care diagnostics applications.

A robust superhydrophobic ZnO coating on a filter paper substrate was successfully prepared for the first time by using a successive deposition process and chemical modification. The surface morphology, chemical composition, wetting property, mechanical stability, chemical stability and durability of the filter papers were examined. The as-prepared papers exhibited an improved rough surface topography compared with the uncoated paper due to the uniform ZnO microclusters decorated on the reticular fibers. More importantly, it was found that the wettability of papers was dependent on the surface roughness, which was governed by the number of ZnO microcluster deposition cycles. After the chemical modification with stearic acid, the resulting paper with 4 cycles presented the optimized superhydrophobicity with a water contact angle (WCA) of 158°, a slide angle (SA) of 3°, a low adhesion and good bounce performance. The chemical resistance of the superhydrophobic paper to corrosive liquids was studied. Moreover, the superhydrophobicity of paper was not affected after the water drops impact test or it was kept for 6 months, indicating its high impact resistance and long-term stability. The excellent superhydrophobicity of paper can be attributed to the synergistic effect of the suitable micro/nanoscale hierarchical roughness and the low surface energy modification.

Photodetectors based on organic–inorganic hybrid are promising which can combine the merits like function tunability of organic materials as well as broadband absorption, excitonic mechanisms and high carrier mobility of inorganic materials. Flexible thin film photodetectors based on inorganic WSe2 nanosheets and organic PANI by tuning composition are developed by simple, cost effective solution blending process. The fabricated hybrid thin films on filter paper substrate manifest visible light detection with high responsivity, fast photoswitching and high specific detectivity. In addition, the performance of hybrid film is retained even after 400 bending cycles. In case of WSe2-PANI hybrid films, the enhanced photoresponse is due to change in work function between PANI and WSe2 nanosheets, local electric fields are formed at WSe2-PANI interface thereby generating a greater number of photogenerated electrons. Compared with other hybrid-based photodetectors, this work advocates huge development in future applications in wearable electronics, security surveillance, high-performance optoelectronics, etc.

Honeycomb-like zinc oxide structures were prepared on the surface of cellulosic materials including cotton fabric fiber and filter paper fiber through plasma treatment followed by wet chemical reaction, the effect of plasma treatment is to increase the wettability and reactivity of cellulosic materials, so that the zinc oxide can nucleate and grow into a honeycomb-like structure on the cellulose fibers. The superhydrophobic surface was then obtained by modifying stearic acid on the zinc oxide structure. The microstructure, chemical composition and state, and wettability of the cellulosic materials were studied in detail. After the modification, the water contact angle and water sliding angle of the modified cotton fabric were 151° and 3.4°, respectively, and those of the modified filter paper is 154° and 4.5°, which indicates super-hydrophobicity. Due to the structural characteristics of zinc oxide-stearic acid structure, the superhydrophobic structure can maintain superhydrophobic performance in strong acidic or strong alkaline environments or after ultrasonic vibration treatment. Further, superhydrophobic modified cotton fabric and filter paper can be used for oil–water separation and adsorption of oil droplets in aqueous solution, and the oil–water separation efficiency is greater than 90%. This method of superhydrophobic modification of cellulosic materials has broad application prospects.

Inkjet-printing of metal nanoparticles is a particularly promising technique for the fabrication and modification of surfaces with a multifunctional nature. Recently copper sulfide nanoparticles (CuS NPs) have attracted wide interest due to a range of valuable properties including long term stability, photo-thermal activity, ease of synthesis and low cost. In the present study, printed CuS patterns were successfully fabricated on latex coated paper substrates and characterized by means of atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), UV–Vis-NIR spectroscopy, and grazing incidence X-ray diffraction (GID). The resulted patterns displayed pronounced photo-thermal effect under Near Infrared Irradiation (NIR) even with relatively low laser power. Finally, by utilizing an automated real-time imaging platform it was possible to verify that the CuS printed film was not cytotoxic to human dermal fibroblast cells (HDF). The pronounced photo-thermal properties and nontoxic nature of these printed low-cost flexible CuS films make them promising candidates for fabrication of devices with localized photo-thermal effect suitable for biomedical applications.

Fe3O4 nanoparticles were modified by tetraethoxysilane and different amounts of trimethoxy (1H,1H,2H,2H-heptadecafluorodecyl) silane in sequence to obtain the magnetic nanoparticles with low surface energy, which could be used to construct the superhydrophobic surfaces for PU sponge, cotton fabric, and filter paper by a simple drop-coating method. Particularly, all the resultant Fe3O4/PU sponges containing different fluoroalkylsilane-modified Fe3O4 nanoparticles possessed both high water repellency with contact angle in the range of 150.2–154.7° and good oil affinity, which could not only effectively remove oil from water followed by convenient magnetic recovery but also easily realize the oil-water separation as a filter only driven by gravity. The Fe3O4/PU sponges showed high absorption capability of peanut oil, pump oil, and silicone oil with the maximum absorptive capacities of 40.3, 39.3, and 46.3 g/g, respectively. Such novel sponges might be a potential candidate for oil-water separation as well as oil absorption and transportation accompanied by the advantages of simple process, remote control by magnetic field, and low energy consumption.

In the long running of oil-immersed transformers, it is inevitable for the oil and insulating paper in transformers to decompose, which can lead to degradation of their insulation performance. Moreover, without timely detection to deal with the equipment failure, electric discharge occurs in transformers, which will affect the stability and security of the whole power system. In this paper, MoSe2 modified by Au and its cluster are proposed to adsorb both single and double C2H4 gas molecules, one of the typical decomposition products of the oil and paper in transformers. Based on DFT, adsorption systems were built and analyzed by analyzing adsorption parameters, DOS, and molecular orbit. The adsorption ability to single C2H4 molecule is in order as: Au3 > Au2 > Au > Au4, and Au4 > Au3 > Au2 > Au to double C2H4 molecules. Moreover, After C2H4 adsorption, the conductivity of Au and Au4 doped systems enhances, while that of Au2 and Au3 systems reduces for both single and double C2H4 adsorption systems. According to the results, Au3-MoSe2 can be a promising material as C2H4 adsorbent and gas sensor applied in detecting and diagnosing the discharge fault in oil-immersed transformers.

Reduced graphene oxide (RGO), a two-dimensional (2D) system, has attracted much interest in photonic applications owing to its ability to absorb light over a broad wavelength. This leads to several studies on RGO-based photosensors. In this paper, chemical oxidation of graphite was carried out at room temperature for the preparation of large area reduced graphene oxide using a modified Hummer’s method. The as-prepared reduced graphene oxide was characterized by XRD, Raman spectroscopy, FESEM, and TEM to confirm the absence of impurities and to ascertain their morphology. In addition, the as-prepared reduced graphene oxide for its possible application as UV photosensor is reported. The electric and optoelectronic properties of RGO based UV photosensor shows a fast response and recovery time of 1 s and 3 s; high photoresponsitivity (3.74 AW −1 ) and quantum efficiency (1274%) indicating that the graphene oxide is an important material for high performance photosensor. This work demonstrates the ultrafast photoresponse with high photoresponsivity, proving its potential as a promising material for optoelectronic devices.

Graphene oxide (GO) synthesized from a flake-type of graphite powder, which was oxidized by various oxidizing agents, temperature control and two sets of drying processes, was electrophoresed on steel substrate for corrosion protection evaluation. The surface morphology, phase crystallization and defect states were determined by Electron microscopy equipped with an Energy dispersion spectrometry, X-ray diffraction and Raman and infrared spectra. The degrees of graphene oxide formation, intercalated defects and crystalline were observed by the impurities’ changes and extending d-spacing. Besides, the BET, Zeta potential and electrochemical impedance spectra were measured to evaluate corrosion protection performance of GO electrophoresis deposition on steel. A strong oxidizing agent (NaNO3) with freeze drying provides high oxygenated functional groups in GO, thus, providing good corrosion protection against hydrochloric acid aqueous due to dense electrophoresis deposition, a lower corrosive current and high resistance of the carrier pathway.

In this study, the surface characteristics, water vapor interactions, and state of water adsorbed on unmodified and coated paper samples were investigated in an attempt to obtain a better understanding of the fundamental principles related to thermodynamics of this process, as well as to provide essential insight that could be used for further improvement of the papers’ barrier properties. Based on the BET measurement, the coated paper samples showed higher specific surface areas than unmodified paper; however, their mean pore diameters are smaller. The BJH method was used for pore size distribution analysis. Hydrophobic properties of the paper samples were determined from experimental isotherms, e.g., monolayer moisture content, and these results have been related to the water vapor transfer rates (WVTRs) showing a complex nature of these relations. The highest peak corresponding to the modified samples with smaller pore sizes was found to be in the range of 1–30 nm, while it was in the 30–100 nm pore size range for unmodified paper. The net isosteric heats of sorption for different unmodified and modified paper samples were determined from water vapor adsorption isotherms measured at 15, 25, and 35 °C. The net isosteric heats of sorption decreased with an increase of moisture content after reaching the maximum values at 12.53, 15.25, 14.71, 23.2, and 22.77 kJ/mol for unmodified, zein grafted, calendered coated, PLA, and PHBV coated papers, respectively. The state of adsorbed water and water-vapor interaction on paper surface were also studied by TGA–DSC and FT-IR spectroscopic techniques. The FT-IR results revealed the formation of water vapor clusters due to poly-layer formation at the higher relative humidity. This has a profound effect on the equilibrium properties, e.g., the intensity of interactions between water molecules and the paper surface decreases as the relative humidity (moisture content) increases. Percentage of bound and unbound water formation and also the dehydration energy at various relative humidities were determined for the paper samples using the TGA–DSC technique.

In this paper, we study the elaboration method of knit polyester fabrics coated respectively, with graphene oxide, graphene and graphene/silver nanoparticles using a cost-effective and scalable approach. This coating approach allows for uniform deposition and good adhesion as well as low, diffuse reflectance. Interestingly, the treated fabrics demonstrate good flexibility, stretchability and foldability, while maintaining lightweight and durability. In addition, PES-G (polyester coated by graphene) and PES-G/Ag° (polyester coated by graphene/silver nanoparticles) exhibit uniform low electrical resistivity because of conductive network of graphene nanosheets and silver nanoparticles formed on the surface of polyester fabrics. Furthermore, the incorporation of low amount of silver nanoparticles into fabrics coated graphene exhibit high flexibility as well as UV blocking properties compared with those coated graphene oxide and graphene. Therefore, the results of this study confirm for the first time that silver nanoparticles and graphene coated into polyester fabric can be obtained with high mechanical and UV protection performances using simple approach. These promising results support the idea that the present approach is useful for the fabrication of flexible, stretchable, conductive and UV protector fabrics for diverse applications because of its low cost, large-scale process and compatibility.

Three-dimensional sponge-like reduced graphene oxide/silicon/carbon nanotube composites were synthesized by one-step hydrothermal self-assembly using silicon nanoparticles, graphene oxide and amino modified carbon nanotubes to develop high-performance anode materials of lithium ion batteries. Scanning electron microscopy and transmission electron microscopy images show the structure of composites that Silicon nanoparticles are coated with reduced graphene oxide while amino modified carbon nanotubes wrap around the reduced graphene oxide in the composites. When applied to lithium ion battery, these composites exhibit high initial specific capacity of 2552 mA h/g at a current density of 0.05 A/g. In addition, reduced graphene oxide/silicon/carbon nanotube composites also have better cycle stability than bare Silicon nanoparticles electrode with the specific capacity of 1215 mA h/g after 100 cycles. The three-dimension sponge-like structure not only ensures the electrical conductivity but also buffers the huge volume change, which has broad potential application in the field of battery.

A one-step strategy for preparing 3D mesoporous graphene networks (3DMGNs) based on the concepts of space-confined effect, catalytic effect and chemical activation is reported in this work. The soluble salts act as the in-situ templates to confine the thickness of 3D graphene layers. Meanwhile, the Fe-catalysts greatly improve the graphitization of the graphene matrix, which are easy to be removed by acid treatment. In addition, the KOH activation introduces abundant mesopores into the graphene networks, which facilities the electrolyte permeation. Thus, when using as electrode materials for supercapacitor, the as-obtained 3DMGNs with high electron conductivity, large surface area and hierarchical porous structure exhibit excellent capacitive properties, including high specific capacitance (215 F g−1 at 0.5 A g−1) and superior rate performance (168 F g−1 at 50 A g−1).

Graphene shows great promise as a high-efficiency electrothermal film for flexible transparent defoggers/defrosters. However, it remains a great challenge to achieve a good balance between the production cost and the properties of graphene films. Here, we proposed a cost-effective self-assembly method to fabricate high-performance, large-area graphene oxide/electrochemically exfoliated graphene hybrid films for heater applications. The self-assembled graphene hybrid films with the area of 20 × 20 cm2 could be transferred onto arbitrary substrates with nonplanar surfaces and simply patterned with the hard mask. After reduction by hydrogen iodide vapor followed by 800 °C thermal treatment, the hybrid films with the transmittance of 76.2% exhibit good heating characteristics and defogging performance, which reach a saturation temperature of up to 127.5 °C when 40 V was applied for 60 s.

The behaviour of gold electrode modified with polyaniline/graphene oxide composites (PGO) was studied for electrochemical and charge storage properties in aqueous acidic media. The surface of gold electrode was modified with aqueous slurry of PGO by using Carboxymethyl cellulose (CMC) as binder. The intercalation of polyaniline in the GO layers, synthesized by in situ polymerization was confirmed by scanning electron microscopy (SEM). The electrochemical behaviour and charge storing properties were investigated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS). A high specific capacitance of 1721 F g−1 was obtained for PGO with 69.8% retention of capacitance even after 1000 voltammetric cycles in the potential range of 0–0.9 V at 20 mV s−1. EIS indicated low charge transfer resistance (Rct) and solution resistance (Rs) values of 0.51 Ω and 0.07 Ω, respectively. This good performance of PGO coated electrode is attributed to the use of CMC binder which generate a high electrode/ electrolyte contact area and short path lengths for electronic transport and electrolyte ion.

How to uniformly disperse graphene sheets into the electrolyte is one of the main challenges to synthesize graphene enhanced nanocomposites by electrodeposition. A surfactant-free colloidal solution comprised of copper (II)-ethylene diamine tetra acetic acid ([CuIIEDTA]2−) complexes and graphene oxide (GO) sheets is proposed to electrodeposit reduced graphene oxide/copper (RGO/Cu) composite coatings. Anionic [CuIIEDTA]2− complexes stably coexist with negatively charged GO sheets due to the electrostatic repulsion between them, facilitating the electrochemical reduction and uniform dispersion of GO sheets into the copper matrix. The RGO/Cu composite coatings are well characterized by XRD, Raman, SEM and XPS. Their tribological behavior as a function of RGO content in composite coatings and normal loads are investigated. Also the chemical composition and topography of the wear tracks for the composite coatings are analyzed to deduce the lubricating and anti-wear mechanism of RGO/Cu composite coatings.

In this work, a comparison study was carried out to investigate the efficacy of glass fiber (GF) in reinforcing poly(lactic acid) (PLA) by using traditional silane coupling agents (GF-S) and novel graphene oxide (GF-GO) as surface modifiers. The crystallization behavior of the PLA matrix was investigated by differential scanning calorimetry. The mechanical performances and the thermomechanical properties of the composites were evaluated by uniaxial tensile testing and dynamic mechanical analysis, respectively. For neat GF without any treatment, the poor interfacial adhesion and the sharp shortening of the GF length result in the relatively poor mechanical performances of PLA/GF composites. However, the incorporation of GF-S significantly improves the mechanical strength and keeps relatively good toughness of the composites, while GF-GO exhibits excellent nucleation ability for PLA and could moderately increase the modulus of the composites. The thermomechanical properties of the composites are improved markedly resulting from the crystallinity increase. The different surface modification of glass fiber influences the crystallinity of matrix, the interfacial interaction and the length of fiber, which altogether affect the mechanical performances of the prepared PLA/GF composites.

Because graphene is carbon material and has excellent mechanical characteristics, its use as ultrathin lubrication protective films for machine elements is greatly expected. The durability of graphene strongly depends on the number of layers and the load scale. For use in ultrathin lubrication protective films for machine elements, it is also necessary to maintain low friction and high durability under macroscale loads in the atmosphere. In this study, we modified the surfaces of both monolayer and multilayer graphene by fluorine plasma treatment and examined the friction properties and durability of the fluorinated graphene under macroscale load. The durability of both monolayer and multilayer graphene improved by the surface fluorination owing to the reduction of adhesion forces between the friction interfaces. This occurs because the carbon film containing fluorine is transferred to the friction-mating material, and thus friction acts between the two carbon films containing fluorine. On the other hand, the friction coefficient decreased from 0.20 to 0.15 by the fluorine plasma treatment in the multilayer graphene, whereas it increased from 0.21 to 0.27 in the monolayer graphene. It is considered that, in the monolayer graphene, the change of the surface structure had a stronger influence on the friction coefficient than in the multilayer graphene, and the friction coefficient increased mainly due to the increase in defects on the graphene surface by the fluorine plasma treatment.

Motivated by the photocatalytic reactions of small molecules on g-C3N4 by these insights, we sought to explore the adsorption of H2O and CO2 molecules on the graphene side and H2O, H2, O2, CO, NO, and CO2 molecules on the g-C3N4 side of hybrid g-C3N4/graphene nanocomposite using first-principles calculations. The atomic structure and electronic properties of hybrid g-C3N4/graphene nanocomposite is explored. The adsorption of small molecules on graphene/g-C3N4 nanocomposite is thoroughly investigated. The computational studies revels that all small molecules on graphene/g-C3N4 nanocomposite are the physisorption. The adsorption characteristics of H2O and CO2 molecules on the graphene side are similar to that on graphene. The adsorption of H2O, H2, O2, CO, NO, and CO2 molecules on the g-C3N4 side always leads to a buckle structure of graphene/g-C3N4 nanocomposite. Graphene as a substrate can significantly relax the buckle degree of g-C3N4 in g-C3N4/graphene nanocomposite.