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This report presents an investigation into the use of carbon paper electrodes prepared from chitosan-adhered graphene magnetite nanoparticles for the analysis of Cr(VI). The preparation and storage of carbon paper electrodes is a simple process, and these electrodes are easier to replace than electrodes modified by more conventional methods. The electrochemical detection of Cr(VI) using square wave adsorption cathodic dissolution voltammetry (SWAdCSV) with high selectivity and sensitivity, as well as the optimum conditions for the preparation of the electrodes and the electrode parameters affecting the SWAdCSV signal, were the main points of focus of the investigation. Cr(VI) was detected linearly in the range of 4-40 μg L-1 with a detection limit of 2.84 μg L-1. The electrode output precision, calculated as %RSD, was 7.16% (n = 6), and this was the measurement used for the detection of Cr(VI) in standard and test samples with recoveries between 89% and 114%. The results were consistent with those obtained using the standard UV-Vis spectrophotometric method with a paired t-test at 95% confidence level. [ABSTRACT FROM AUTHOR]

Selective enrichment of La(III) by green material as an industrial raw material is of great research interest. In this study, the selective interaction between P and La(III) was utilized, and waste paper (WP) modified with phytic acid (PA) was used to adsorb La(III) from water using a simple one-pot method. The adsorption capacity was 237.23 mg g−1 (30 °C, pH = 5, initial concentration of 200 mg L−1). The equilibrium isotherm fitted the Langmuir isotherm model well. The adsorption equilibrium was reached after 15 min. The adsorption kinetics followed the pseudo-second-order kinetic model, indicating that the adsorption mechanism of the material towards La(III) is single-layer chemisorption. It selectively adsorbed La(III) from four coexisting substances (Pb, Ni, Cu, and Co). After six cycles, the adsorption efficiency of the adsorbent material remained at 60%. [ABSTRACT FROM AUTHOR]

Employing a one-pot Schiff-base condensation approach, the derivative "cholyl hydrazide Schiff base of phenothiazine" (ChHSB-PTZ) based on cholic acid has been synthesized and characterized via standard procedures. ChHSB-PTZ demonstrates exceptional sensitivity towards Sn(II) metal ion detection through fluorescence "turn-off" behavior based on chelation-enhanced fluorescence quenching (CHEQ) even in the presence of various cations and anions. Through modified Stern–Volmer and Stern–Volmer graph analyses, the binding constant (Ka) and limit of detection (LOD) were found to be 2.8 × 1010 M−1 and 2.2 nM, respectively. A 1 : 1 stoichiometry between ChHSB-PTZ and the Sn(II) metal ion was found via Job's plot. Moreover, the distribution of electronic states in the ChHSB-PTZ Schiff base and the sensing mechanism (CHEQ) were clarified through the use of 1H NMR titration spectroscopy and density functional theory (DFT) calculations. ChHSB-PTZ test paper strips are developed as an essential tool to improve the analytical applicability of the device and enable the rapid, accurate, and affordable detection of Sn(II) metal ions in environmental analysis. [ABSTRACT FROM AUTHOR]

As a kind of organic basic compound containing nitrogen, biogenic amine is released from food spoilage and considered as an indicator for monitoring food freshness. Herein, an excellent dual-emission ratiometric fluorescent sensor for eight kinds of biogenic amines was established via the facile mixing of pH-responsive carbon dots and Rhodamine B. The developed sensor shows a rapid response (10 s), low limit of detection (0.733–3.943 μM) and a wide linear range (0–150 μM). More importantly, a portable fluorescent filter paper was prepared by simple dispersing the filter paper in a solution mixture of carbon dots and Rhodamine B. The obtained fluorescent filter paper based sensor showed an obvious color change in the presence of biogenic amine vapor derived from shrimp and mushroom. The results revealed that this sensor could realize the on-site and visual detection of biogenic amines in real food samples, making it suitable for potential application in food safety monitoring. [ABSTRACT FROM AUTHOR]

Developing new forms of flexible zinc–air (Zn–air) batteries is crucial to economic growth. Nevertheless, the absence of an oxygen evolution reaction catalyst with high catalytic efficiency and low-cost causes instability of Zn–air battery cycling and economic unviability, respectively. In this paper, a leaf-like N-doped carbon structure with CoS2 nanoparticles self-supported on carbon fiber paper (CoS2-CZ@CFP) was developed as an air electrode for Zn–air batteries, which not only uses nonprecious metal elements, but also has a self-supporting configuration, enhancing the contact between the catalyst and electrode while facilitating the transfer of electrons. Sulfur as the source gas was introduced into Co-doped metal–organic skeletons (Co-ZIFs) anchored on carbon fiber paper (CFP) for in situ vulcanizing transition metal Co, which successfully ensures the uniform distribution of sulfide particles in the carbon matrix, hence enriching active catalyst sites. The CoS2-CZ@CFP demonstrated an overpotential of 1.611 V at J = 50 mA cm−2, superior to RuO2@CFP (1.814 V). A Zn–air battery fabricated using the synthesized CoS2-CZ@CFP exhibited an extended life cycle of 117 h. This research paves the way for a novel method of designing self-supporting configurations of sulfides and carbon matrix composites as promising air electrodes applicable to Zn–air batteries. [ABSTRACT FROM AUTHOR]

A robust superhydrophobic filter paper was developed through a coating technique, simple and facile, cost-effective, eco-friendly, and defensible, for wide portfolio applications. To develop super hydrophobic filter papers, the paper was coated with inorganic–organic hybrid nanocomposites comprising zinc oxide, chitin, and polycaprolactone (chitin–ZnO–PCL) and zinc oxide, chitosan, and polycaprolactone (chitosan–ZnO–PCL) hybrids through the grafting method. The preparation of a superhydrophobic surface by dip-coating deposition is a facile process. Zinc oxide nanoparticles grafted with chitin–PCL and chitosan–PCL hybrids coated on paper exhibit superhydrophobic properties. Water contact angle measurement carried out using a goniometer showed the average static water angle values of 145° and 160° for the chitin–ZnO–PCL and chitosan–ZnO–PCL grafted hybrid coated surfaces, respectively. The surface morphology of the coating was studied using scanning electron microscopy, X-ray powder diffraction, UV radiation, and Fourier transform infrared spectroscopy. In addition, durability, oil/water separation, bio-degradability, and self-cleaning ability through water flush-out were also studied and reported. The results show that the coated filter papers possess excellent superhydrophobic properties for real-time applications. [ABSTRACT FROM AUTHOR]

Naphthalenediimide derivative-absorbed papers, which were prepared by dropping chloroform solution, showed fluorescence under photoirradiation after exposure to vapors of small aromatic guests. The fluorescence intensity and maximum wavelength depended on the type of guest aromatic molecules, similar to the crystal. The naphthalenediimide derivative-absorbed papers showed vapochromic and mechanochromic properties. [ABSTRACT FROM AUTHOR]

A simple, portable and cost-effective paper-based analysis device is developed for quantitative determination of ascorbic acid (AA) based on the UV-induced oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). The method does not involve the introduction of any enzyme or external oxidants. More importantly, large equipment is not needed and only a 20 μL sample is needed for each analysis which only takes 8 min. The filter paper is pre-treated with TMB and it turns blue upon UV irradiation because TMB is a self-photosensitizer. The phenol hydroxyl groups of AA can inhibit photo-triggered oxidation resulting in a lighter blue color. The color signal is captured using a smartphone and analyzed using color analysis software. A series of factors that affect the performance of the device are investigated, including the concentration of TMB, buffer pH, channel selection, and irradiation time. The analytical performance is evaluated, and the results show that the method has a wide detection range of 0.05–1.0 mmol L−1 as well as a high selectivity and reproducibility. The proposed method is applied for assaying AA in beverage samples and a VC tablet, and the results correspond to those obtained using the UV method. The results of the recovery test of human serum indicate that the proposed method is feasible in biological samples. This device is easy to fabricate, and convenient to store and transport. It is a truly portable device which has great potential in the on-site assay. [ABSTRACT FROM AUTHOR]

Viologens exhibit excellent color responses to external stimuli owing to their desirable redox properties. They have been widely studied in electrochromic and photoluminescent materials. Generally, polymeric materials have better processing properties and longer service life than small organic molecules. Herein, a viologen-containing polyurethane was synthesized and used to prepare an electrochromic device and a paper-based amine detector. The obtained electrochromic device displayed an excellent electrochromic behavior when subjected to an external voltage as low as 1.0 V. Moreover, the designed paper-based amine detector exhibits a highly sensitive color-change response when exposed to liquid amine solutions (down to 1 ppm concentration) or gaseous ammonia. The results of this study demonstrated that the developed viologen-containing polyurethane exhibits excellent electrochromic performance and the designed amine-detecting paper chips are an excellent tool for amine detection. [ABSTRACT FROM AUTHOR]

Sulphur doped graphitic carbon nitride (SGCN) was effectively prepared and comprehensively described. A straightforward synthetic process based on thermal condensation was reported for the synthesis of SGCN using thiourea as a precursor. Cyclic voltammetry (CV) and differential pulse voltammetry were used to evaluate the electrochemical performance of cortisol. SGCN sheets were used to boost the electro-catalytic activity, exhibiting very exceptional electrochemical behaviour towards cortisol. As a result, we obtained a broad linear response range of 0.1–100 μM, as well as a comparatively low detection limit (15.8 × 10−8 M). Furthermore, the fabricated SGCN/CFP electrode shows excellent selectivity in the presence of a large number of possible interfering species. SGCN comprises (C with N and S) heteroatoms, which most likely would have led to a better current response towards cortisol detection. Furthermore, the structural defects that generate additional active sites on the surface of SGCN may enhance the quick electron transfer that occurs during the oxidation of cortisol. [ABSTRACT FROM AUTHOR]

The water-soluble bromophenoxy-substituted naphthalimide derivative 1 and its copolymer P1 with acrylamide were synthesized and the photophysical properties of their host–guest complexes with cucurbit[8]uril (CB[8]) were studied. Notably, the host–guest complex CB[8]·1 showed long-lived RTP on filter paper and demonstrated a humidity response, making it suitable for use as an encryption ink. Furthermore, the solid powder of the host–guest complex between P1 and CB[8] exhibited a 4 s afterglow emission. [ABSTRACT FROM AUTHOR]

Valproic acid (VPA) is mainly used in the clinic to treat epilepsy, for which the therapeutic window is narrow to avoid causing adverse reactions such as hepatotoxicity and teratogenicity. Therefore, timely therapeutic drug monitoring is needed. A hapten containing a benzene ring and an amino group was designed and used to screen a monoclonal antibody (mAb) 3G10 with high specificity and sensitivity. The IC50 value of mAb 3G10 was ascertained as 68.13 ng mL−1 through an indirect competitive enzyme-linked immunosorbent assay. A colloidal gold-based immunochromatographic strip (CG-ICS) for the detection of free VPA in human serum was developed with gold-labeled mAb 3G10. Qualitative analysis of human serum samples can be conducted through visual observation. The visual limit of detection (vLOD) was 2 μg mL−1, and the cut-off value was 100 μg mL−1. A standard curve for quantitative detection was generated using a portable scanner, with a calculated LOD (cLOD) value of 0.144 μg mL−1 and a linear range of 0.565–48.385 μg mL−1. Comparing the results of CG-ICS for actual positive samples with those of a direct chemiluminescence kit, there was a good correlation between the two methods. Therefore, our CG-ICS can be applied to the rapid clinical monitoring of free VPA. [ABSTRACT FROM AUTHOR]

We report the results of studies relating to the development of a conductive ink-coated, paper-based electrochemical DNA hybridization assay for the detection of the porA pseudogene of Neisseria gonorrhoeae (gonococcal DNA), the causative agent of gonorrhoea. Briefly, a conductive and highly homogenous ink was prepared by dispersing carboxylated MWCNTs (cMWCNTs) in a stable emulsion consisting of terpineol as solvent, carboxymethyl cellulose (CMC) as binder and polysorbate 80 (PS80) as the stabilizing agent. This cMWCNT-based ink was coated onto paper substrates to obtain cMWCNT@paper electrodes with a mean (± standard deviation, SD) resistivity of 1.066 (± 0.33) Ω cm. Furthermore, a magnetic bead (MB)-mediated hybridization assay comprising a specific 5′-biotinylated capture DNA probe (C) and 3′-methylene blue (MetB)-tagged detector DNA probe (D) was designed. These probes hybridized specifically with a porA target DNA sequence (T) forming a sandwich hybridization complex (C-T-D) at the MB surface. Thus formed C-T-D/Av/MB samples with different T concentrations were drop cast and adsorbed onto the cMWCNT@paper for electrochemical detection. The linear detection range and sensitivity of the electrochemical biosensing assay were found to be 100 fM–100 nM and 5.09 μA (log[concentration])−1, respectively. The biosensing assay was further shown to detect the target genomic gonococcal DNA in a mixture consisting of different DNA and protein interferents indicating its clinical viability. The results of rheological studies reveal that this thixotropic cMWCNT ink can be utilized for screen printing. These studies demonstrate the utilization of a conductive ink formulation for the fabrication of paper-based electrochemical sensing electrodes having high potential for cost-effective batch production and application in point-of-care (PoC) clinical diagnostics. [ABSTRACT FROM AUTHOR]

Pesticide residues are a serious problem towards agriculture, environment and food safety, so it is highly desirable to develop a swift, efficient and portable pesticide detection method. A fluorescence visual sensing method for glyphosine based on a nitrogen-doped biomass carbon quantum dot (N-CQD) paper-based sensor was developed. The fluorescence signal was quenched by Fe3+ in a static quenching process, and then the fluorescence of N-CQDs was recovered after adding glyphosine. Under the optimal experimental conditions and when tested with a fluorescence spectrofluorometer, the detection of glyphosine showed a two-stage linear pattern in the range of 0.1–0.6 μM and 0.6–1.6 μM with a detection limit of 0.075 μM. Then, the RGB values of different concentrations of glyphosine on the filter paper chip were detected by the software of the smartphone-color identifier. The logarithm of the glyphosine concentration was linearly related to the G value of RGB in the range of 0.25–10.00 mM and with a detection limit of 0.15 mM. The method was applied to measuring glyphosine-spiked juice and flour samples, and the recovery rates were 87.60–112.69% and 93.27–105.83%, respectively. The proposed N-CQDs/Fe3+ system had wide applications, and it was expected to be fast and effective at detecting pesticide residues. [ABSTRACT FROM AUTHOR]

A new fluorescent probe (T2) containing pyrene-hydrazone furan moieties was developed and synthesized through a two-step process and then coated onto filter paper to form a paper-based sensor for TNT detection. The T2 sensor uses photoinduced electron transfer (PET) induced fluorescence quenching to detect TNT. The sensor properties were studied using fluorescence spectra, 1H-NMR titration and density functional theory (DFT) calculations. The reaction time of the T2 paper-based sensor for TNT detection was only five minutes. A smartphone was used as an alternative instrument to detect fluorescence signals and a typical image J-processing application was employed to evaluate the grayscale values of the smartphone-captured photographs. The sensor showed a linear concentration range for TNT detection of between 30–500 μM and a detection limit of 30 μM. The T2 paper-based sensor was found to have high selectivity and sensitivity, and it can successfully detect and image TNT in actual samples. This research demonstrates that a T2 paper-based sensor is a promising alternative for TNT detection owing to its short reaction time, high selectivity, sensitivity, and easy applicability. [ABSTRACT FROM AUTHOR]

Metabolic alkalosis, the most common acid–base disorder, is related to significantly increased mortality in hospitalized patients. Hunting for pH sensors lying in the neutral to alkaline pH range still remains challenging and in demand. Herein, we engineered a colorimetric/fluorescent method for monitoring alkalic pH based on a phenylboronic acid-containing probe (DDPB). In this approach, the dicyanoisophorone group of DDPB acted as an optical signal moiety, while the boronic acid acted as the latent pH response site. It was exactly deciphered that the reversible pH monitoring principle is based on the deprotonation/protonation mechanism and intramolecular charge transfer (ICT) strategy via1H NMR and DFT calculations. This approach presented a pH-sensitive response over pH values ranging from 7.00 to 10.23 (pKa = 9.33) with excellent reversibility. We further explored its application in sensing pH on a paper substrate for visual and rapid detection. In addition, it was successfully applied to measure pH variations in HK-2 cells when the cells underwent alkalosis. This work extends the application of optical probes based on boronic acid under alkaline pH conditions, and provides a new strategy for the design of alkaline pH probes. [ABSTRACT FROM AUTHOR]

Electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) has received increasing attention as it is an eco-friendly strategy for synthesizing a key monomer for the production of bio-based plastics. Developing efficient, low-cost and stable electrocatalysts is crucial for this electrochemical reaction. In this work, we have reported a facile process for the synthesis of hybrid nanosheet-structured NiCo2O4 on carbon fiber paper (NiCo2O4-CFP) for the efficient electrochemical conversion of HMF into FDCA. As a non-noble binary metal-based catalyst, NiCo2O4-CFP featured a nanosheet network and 3D nanosheet flower-like microspheres, showing 94.3% selectivity and 89.6% faradaic efficiency (FE) for FDCA, which outperformed its single component metal oxides NiO-CFP and Co3O4-CFP. And it also exhibited relatively high stability by maintaining over 80% FE after four successive cycles. The proposed mechanism suggested that the synergistic effect of Ni and Co elements in NiCo2O4 could facilitate HMF oxidation. [ABSTRACT FROM AUTHOR]

As a part of our ongoing research, we have synthesized a new fluorescence probe, p-C4A, based on a calix[4]arene substituted with 4-aminoquinoline moieties with amide linkages. p-C4A can selectively recognize Li+ and PO43− ions and has been characterized via an emission study, an absorption study, ESI-MS spectroscopy, a 1H NMR study and cyclic voltammetry. The fluorescence sensor p-C4A can operate over a concentration range of 5–170 nM for Li+ sensing and 5–80 nM for PO43− sensing. The R2 values obtained for the sensing of Li+ and PO43− ions are 0.9962 and 0.9911, respectively. p-C4A demonstrates a minimum detection limit of 6.15 nM for Li+ and 9.0 nM for PO43−. The quantum yields of p-C4A as its Li+ and PO43− ion complexes were found to be 0.014 and 0.27, respectively. Herein, we report an easy-to-use, low-cost, disposable, paper-based, fluorescent, wax-printed device for the rapid chemical screening of Li+ and PO43−. This device can be used as a quick, portable, multiple-test panel that is simple, lightweight, and disposable. Moreover, in order to assess its analytical applicability, the prepared sensor was successfully used for the determination of Li+ and PO43− from wastewater samples, validating the proposed ion recovery method with 96–99% recovery rates. [ABSTRACT FROM AUTHOR]

It is significant to develop low-cost and highly efficient electrocatalysts for the hydrogen evolution reaction (HER) via electrochemical water splitting. Herein, we constructed P-doped NiCo2S4 nanowire arrays on carbon fiber paper (NiCo2S4−xPx/CFP) as a HER electrocatalyst in both acidic and alkaline media. Benefitting from P doping into NiCo2S4, the as-prepared NiCo2S4−xPx/CFP exhibits low HER overpotentials of 80 and 132 mV in acidic and alkaline media at a cathodic current density of 10 mA cm−2, respectively, which are far superior to counterparts of NiCo2S4 nanowire arrays on the carbon fiber paper (NiCo2S4/CFP). Meanwhile, the NiCo2S4−xPx/CFP presents excellent HER stability of 20 hours in acidic and alkaline media. From the results of density functional theory calculations, P doping can not only optimize the hydrogen adsorption energetics on each kind of atomic site of catalysts, but also strengthen the H2O molecule binding ability on the catalyst surface for the alkaline HER and favor kinetics of hydrogen adsorption and H2 formation on the catalyst surface for the acidic HER, eventually improving overall HER performances. The investigation of the HER mechanism modulated by P doping in our work offers novel inspiration to develop highly efficient ternary metal sulfides for the HER. [ABSTRACT FROM AUTHOR]

A chromone-based symmetrical dipodal Schiff base probe L was designed and synthesized for multi-analyte detection in both aqueous and organic media. L displayed a prominent 'turn-on' fluorescence response with Al3+ (LOD = 6.9 μM) via the chelation-enhanced fluorescence (CHEF) process in a fully aqueous medium based on the inhibition of the photoinduced electron transfer (PET) process. Moreover, the in situ generated [L-Al3+] system was able to detect pyrophosphate (PPi) under identical experimental conditions. The proposed sensing pathway is believed to be the complexation with aluminium, followed by the subsequent decomplexation of the system by PPi. Furthermore, as the probe was decorated with –NH functionalities, it attained fluorescence indications upon binding with a basic anion. The detection ability of the probe for fluoride ions (LOD = 6.8 × 10−8 M) in the organic medium was studied using the 'turn-off' emission change based on the formation of a N–H⋯F hydrogen bond and subsequent deprotonation, as well as a visual change in color from yellow to reddish-yellow under UV light. The in situ prepared [L-F−] adducts could potentially sense Zn2+ ions with a 'turn-on' response via the metal-induced release of the free probe. All of the spectroscopic analyses were recorded to support the recognition mechanism of the aforementioned analytes by the reported probe molecule L. The probe also found applications in testing real water samples. [ABSTRACT FROM AUTHOR]

The sustainable goal of technological advancement is to go from lab to site through the development of a sensitive, specific and portable sensor for pollution monitoring. Herein, we report a completely portable colorimetric prototype device for the selective monitoring of lead (Pb) pollution, mainly in air, which relies on a new aspect of analysing the colorimetric assays on paper strips by the direct measurement of the retroreflective information, other than the available tedious image analysis methods. Our indigenously developed citrate-functionalized silver nanoparticles (AgNPs) embedded in cellulose paper strips showed significant localized surface plasmonic resonance (LSPR) peaks in the blue region and with the increase in the Pb concentration, the LSPR band in the blue region decreased and a new peak appeared in the green region of the electromagnetic spectrum due to the formation of larger aggregates. The prototype device monitored these spectral changes and accordingly gave the Pb content present in the sample. In this work, we made the sample under study by the acid digestion of one of the widely present air-suspended particulates, i.e., PbO2. The prototype device is a suitable fielddeployable technique for environmental Pb sensing and will open up new perspectives for future advancement in low-cost paper-based sensing. [ABSTRACT FROM AUTHOR]

The integration of smartphones with visual-based paper strips has gained great attention because of the rapid, low-cost, and relible analysis. Herein, we report on the synthesis of a red luminescent europiumbased metal organic framework (Eu-MOF) for the detection of folic acid in pharmaceutical formulations. The Eu-MOF showed strong and stable red emission fluorescence (excited at 270 nm), and the emission was significantly quenched upon exposure to folic acid due to the inner filter effect. A fluorometric assay in solution and visual detection based on fluorescence on a paper strip were used independently to quantify folic acid. The paper strips were prepared using chromatography paper and with the aid of a smartphone, folic acid was visually detected. In solution, the calculated LOD was 0.3 mM with a dynamic linearity range from 1.0 to 12.50 mM. Meanwhile, in the visual detection based on a smartphone integrated with a paper test strip, the linearity was from 1.0 to 9.0 mM with 0.12 mM as the LOD. Color analysis, from the photographs taken with a smartphone, was performed via analyzing the RGB coordinates using the Image-J program. The luminescent probe was applicable to detect folic acid in various drug tablets with recovery data ranging from 95 to 103%. The application of smartphones and fluorescent paper strips provides reliable detection of folic acid for on-site analysis, particularly in remote rural areas. [ABSTRACT FROM AUTHOR]

Recently, hydrogen peroxide (H2O2) has been used as a disinfectant in sanitizers for cleaning hands, and solid surfaces of hospitals, offices and homes to prevent the spread of the COVID-19 virus. The effluents from domestic, hospital and municipal waste should be monitored for their H2O2 content to avoid the entry of this toxic pollutant into the ecosystem. Therefore, we developed a low-cost graphene (Gr)-printed paper electrode for determination of H2O2 using cyclic voltammetry (CV). An office inkjet-printer and Gr nano-ink stabilized with ethyl cellulose (EC) were used for the fabrication of printed paper electrodes (PPEs) to determine H2O2 quantitatively. A stable Gr–EC nano-ink (2%) with viscosity and surface tension values of 12 mPa S−1 and 35 mN M−1, respectively, was formulated to obtain conductive electrodes. A wide linear range (2 μM–25 mM) with a better limit of detection (0.28 μM) for the determination of H2O2 was obtained when the Gr–EC/PPE was used as a working electrode. Further, the Gr–EC/PPE was successfully employed for analysis of H2O2 in wastewater. The electrochemical determination of H2O2 using the Gr–EC/PPE as an electrode in CV is rapid, economical, flexible and eco-friendly when compared with previously reported methods. [ABSTRACT FROM AUTHOR]

The integration of paper-based devices with fluorescent nanomaterials as recognition elements has offered novel opportunities for biosensing with enhanced sensitivity and selectivity, as well as stable signals. This work innovatively designed a fluorescent paper-based device for enantioselective sensing of D -alanine (D -Ala), where carbon dots (CDs) grafted cellulose paper (PCD) was used as the fluorophore and the in situ generated gold nanoparticles (AuNPs) were used as quenchers. D -α-Amino acid oxidase (DAAO) stereo-selectively catalyzed D -Ala to produce hydrogen peroxide (H2O2), which mediated the in situ formation of PCD/AuNPs composites and quenched the fluorescence of PCD based on fluorescence resonance energy transfer (FRET). Under optimal conditions, the designed PCD/AuNPs demonstrated a reliable quenching response to D -Ala in the range of 1–100 μM and the limit of detection was 0.55 μM. Moreover, the platform was applied to detect D -Ala in serum, simulated gastric fluid samples, and was further employed to determine D -Ala in BGC-823 gastric cancer cells with satisfactory results. Ultimately, the PCD/AuNPs platform provided a novel strategy for the development of reliable and sensitive assays based on paper-based devices. It has great potential to be utilized in enantioselective sensing and clinical early diagnosis. [ABSTRACT FROM AUTHOR]

The practicality of portable fluorescent detectors has attracted widespread attention. Herein, a series of luminogens was obtained via integrating pyrrole/fluorinated-pyrrole with triphenylamine in high yield. The emission performance was modified via varying the F and CN substituents on the pyrrole ring. The compounds TPACHO and TPAFCHO, with aldehyde-group-substituted pyrrole, exhibit significant mechanochromic luminescence (MCL) behavior and typical AIEE properties. The compounds TPA2CN and TPA2FCN can efficiently detect liquid and gaseous hydrazine hydrate, and they can achieve paper-based detection through visually clear emission color switching from yellow/orange to blue. The minimum detectable concentration of hydrazine was 10 mM. Moreover, TPA2CN exhibits good inhibitory activity toward human nasopharyngeal tumor cells (CNE1) and it has application prospects in tumor cell detection and biological cell monitoring. Thus, such functionalized paper can be applied as highly selective discriminating test strips for hydrazine hydrate. [ABSTRACT FROM AUTHOR]

The design and preparation of a reduced graphene oxide (rGO) paper electrode with a reinforced concrete structure is an effective strategy to improve the mechanical properties of flexible electrodes. Therefore, PEDOT:PSS is added as a binder, toughening and conductive agent. CNTs, with good mechanical properties, are added to enhance the strength. Fe2O3 nanoparticles are added to increase the energy storage. According to these assumptions, we successfully prepared a flexible hydrophilic paper electrode with rGO nanosheets, PEDOT:PSS, CNTs and Fe2O3 nanoparticles by a constant temperature vacuum drying method. In addition, the assembled symmetrical supercapacitor exhibits a high capacitance of 1924 mF cm−3 at 1 mA cm−3, an excellent energy density of 35.6 W h kg−1 (at 166 W kg−1) and a remarkable cycle stability of 98.2% retention over 10 000 cycles at 1 mA cm−2. [ABSTRACT FROM AUTHOR]

Cellulose is a kind of low-cost, widely-sourced and environmentally friendly material. In this paper, a cellulose acetate/cellulose fiber paper composite membrane was prepared through a phase inversion process. Combining the advantages of these two materials, the composite membrane has good antifouling performance and excellent wear resistance. [ABSTRACT FROM AUTHOR]

One of the primary challenges for the development of electrochemical sensors for dopamine (DA) is the lack of selectivity due to the major interference from ascorbic acid (AA) which is oxidized at a potential close to the working potential of DA. In this work, we present a means for simple and cost-effective electrochemical detection of DA in the presence of interference using a microfluidic paper-based analytical device (eμPAD) to improve the selectivity and sensitivity. The device was made by incorporating the sample separation and the electrochemical detection elements into a single device, which required a single drop of the sample solution. For sample separation, Nafion was cast on the sample zone and microfluidic channel to block AA, before the solution was allowed to continuously flow to the detection zone. A multilayered eμPAD was fabricated by placing a round cotton pad on the detection zone to enable the generation of a quasi-steady flow rate. Thereafter, a packing tape was used to seal the top part of the device to increase the flow rate and prevent volatilization of the sample on the eμPAD. The concentration of DA that could be measured by the poly(glutamic acid) modified screen-printed graphene electrode was in the range of 1–200 μM, and the limit of detection (LOD) was 0.41 μM (3SD/slope). The proposed platform provides an accurate and satisfactory method for the detection of DA in real samples compared with UV-Vis spectroscopy. [ABSTRACT FROM AUTHOR]

Berberine (BBR) is a highly effective animal feed additive, but it also has adverse side effects on animals and causes potential food safety issues. Here, based on the preparation of a BBR monoclonal antibody, we developed a rapid, simple and sensitive lateral flow immunoassay (LFIA) using gold nanoparticle (GNP)- and fluorescent microsphere (FM)-labelled BBR antibodies for quantitative detection of BBR in feed samples. Under a hand-held optical scanner, the limits of detection of the GNP-LFIA and FM-LFIA were found to be 4.40 μg kg−1 and 2.00 μg kg−1, respectively, in feed samples. The spiked feed samples had acceptable recovery rates using the LFIAs, and the results were further confirmed by liquid chromatography/mass spectrometry. The actual feed sample test results by GNP-LFIA and FM-LFIA also showed good consistency. These two LFIAs provide a good option for fast screening of BBR on-site in feed samples. [ABSTRACT FROM AUTHOR]

This work presents the development of a green paper-based analytical device (Green-PAD) array for pH detection. The array was obtained with natural dyes extracted from red cabbage (Brassica oleracea) and butterfly pea flower (Clitoria ternatea); a filter paper was used as a substrate. The RGB indexes of the PADs' colors were extracted from the pictures taken using a smartphone or using a specifically developed RGB detector (Arduino-based) to obtain RGB indexes not affected by the light and the photocamera sensitivity. Multi-technique chemometric models were developed for calculating the pH value, starting from the RGB triplet of each sensing PAD. A preliminary and explorative chemometric analysis with PCA (partial component analysis) and TWPCA (3-way PCA) was carried out. Partial least square regression, PLS, was then applied to correlate the color of the PAD's picture with the solutions' pH. Different solutions at various pHs, ranging from 1 to 13, were obtained by titrating orthophosphoric acid with standardized NaOH, and they were used to create PLS models. Some real samples were examined as a test set, and the results were validated with pH-meter measurements. The ability of the PLS to model the experimental data was satisfactory since a good agreement between the experimental and fitted pH values was obtained. The proposed PADs were prepared with natural dyes and filter papers, so they are completely biodegradable and eco-friendly. Their fabrication does not require toxic or expensive reagents and sophisticated equipment. Also, the developed RGB detector, built-up with low-cost components and recycled batteries, adds value making the measurement cheap, easy and feasible also by non-expert people. [ABSTRACT FROM AUTHOR]

The document is a contents list for the New Journal of Chemistry, a publication that aims to connect the world with the chemical sciences. It provides information about the articles and papers included in the journal's latest issue. The articles cover a range of topics in chemistry, including the structural basis for Cu(II) metallocycle hexamer formation, photocatalyst-free hydrothiolation of gem-difluoroalkenes with thiols, and the construction of an alkynyl-containing porous polymer for enhanced photocatalytic H2O2 generation. The journal also invests its profits back into the chemistry community. Additionally, the document includes a correction to a previous paper on the effect of electrolyte optimization. [Extracted from the article]

The New Journal of Chemistry, published by The Royal Society of Chemistry and the Centre National de la Recherche Scientifique, contains a variety of research papers on topics such as graphite exfoliation, EPR characterization of N-oxyl radicals, anticancer efficacy, protoplast regeneration, semiconducting carbon nanotubes, and electrochemical sensing. The journal aims to provide new directions in chemistry and offers valuable insights and research findings for library patrons conducting research in these areas. The document is a list of papers published in the journal, covering a range of topics in chemistry and materials science, including pH-responsive nanotheranostics, synthesis of fused molecules, removal of tetracycline from water, and comparison of different species using UPLC-Q-TOF-MS. [Extracted from the article]

The document is a contents list for the New Journal of Chemistry, a publication by The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. It features a variety of articles and papers covering topics such as anti-counterfeiting printing, monitoring platinum(IV) complexes, and the removal of uranium from the kidneys. The journal also provides information on training courses and resources for professional development in chemistry. The papers offer valuable insights and advancements in the field, making it a valuable resource for researchers and professionals in chemistry. [Extracted from the article]

The New Journal of Chemistry, published by The Royal Society of Chemistry and the Centre National de la Recherche Scientifique, has released a list of papers published in 2024. These papers cover a wide range of topics in the field of chemistry, including photothermal properties of MXenes, pseudomorphic transformation of silica, and adsorption behavior of chloramphenicol. Other papers explore drug abuse detection in hair samples, photocatalytic performance, small-molecule tracer imaging, catalytic studies, colorimetric sensing, and more. These papers offer valuable research and insights in various areas of chemistry. [Extracted from the article]

The aim of this paper is to evaluate the quality of 13 batches of rice and 17 batches of paddy. Differential scanning calorimetry curves, Fourier transform infrared spectroscopy, ultraviolet spectroscopy and electrochemical curves of 30 batches of rice and paddy were collected, and this paper utilized the quantitative fingerprints evaluated by using the systematic quantitative fingerprinting method, macro qualitative similarity (S m) and macro quantitative similarity (P m) to reflect the internal differences of the samples. A new quality assessment method was explored to quantify the obtained fingerprint profiles and to compare the correlation between the original fingerprints and the quantum fingerprints using a t-test. Using the parameters S m and P m as analysis criteria, hierarchical clustering analysis (HCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and the equal-weight integrated evaluation method were used to evaluate the quality of the four analysis methods. [ABSTRACT FROM AUTHOR]

This document is a contents list for the New Journal of Chemistry, a publication by The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. It provides a list of articles and papers featured in the latest issue of the journal, covering a diverse range of topics in chemistry. Some of the topics include enantioselective insertion of vinyl diazoacetates, building a data science toolbox for designing catalysts, and the synthesis and coordination behavior of a ferrocene phosphinostibine. The document also includes a correction to a previously published paper. [Extracted from the article]

The New Journal of Chemistry is a publication that focuses on the chemical sciences and aims to connect researchers worldwide. The document provided is a contents list for the journal's 2024 edition. It includes papers on various topics such as membrane modification, nanoparticle synthesis, targeted therapy, catalysis, and material properties. Two specific papers are highlighted: one discusses the use of cationic lipids in non-viral gene delivery, while the other explores the confinement of metal-organic framework (MOF) etching-induced hollow structures for enhanced activation of peroxymonosulfate. The journal is published by The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. [Extracted from the article]

High-entropy alloys show broad application prospects in electrocatalysis due to their high catalytic activity, conductivity and structural stability. However, achieving their mild and scalable synthesis still remains a great challenge. This paper reports a strategy for the synthesis of CrFeCoNiRu0.5 high entropy nano-alloy/carbon (termed as CrFeCoNiRu0.5-HENA/C) using a chelate-based ionic liquid. Cr(III), Fe(III), Co(II), Ni(II) and Ru(III) were coordinated with salicylic acid ionic liquid to form a viscous metal complex solution, followed by low temperature carbonization and subsequent high temperature annealing. The resulting CrFeCoNiRu0.5- HENA/C consists of a three-dimensional carbon framework and CrFeCoNiRu0.5-HENA nanocrystal. The carbon framework offers high ion/electron conductivity and good affinity with NO3- and CO2 due to the presence of hydrophilic oxygen-containing groups and highly electronegative nitrogen atoms. The CrFeCo-NiRu0.5-HENA nanocrystal has a small size of 52.5 x 1.2 nm, good element homogeneity and high crystallinity. Such a unique structure improves the adsorption capacity towards NO3 - and CO2 and the electrocatalytic activity towards the C-N coupling reaction. The CrFeCoNiRu0.5-HENA/C electrocatalyst exhibits a high urea yield of 35.57 x 0.81 mmol gcatalyst -1 h-1 with a high faradaic efficiency of 21.02-0.77%, which is much better than that of multi-component nano-alloys from Cr, Fe, Co, Ni and Ru. This study also provides an approach for the construction of high-entropy nano-alloys in catalysis, sensing and energy storage and conversion. [ABSTRACT FROM AUTHOR]

A nanocatalytic antimicrobial gel responsive to the bacterial infection microenvironment (IME) possessing highly specific antimicrobial properties provides an opportunity to address the bacterial drug resistance. However, the pH conditions and low substrate concentration in the IME limit the catalytic antimicrobial efficiency of these agents, resulting in unsatisfactory performance. The reported transition metal peroxide alleviates endogenous substrate insufficiency due to H2O2 self-supplying properties, but still suffers from difficulties of simple synthesis, long-stem storage and lower intrinsic catalytic efficiency responsive to the IME. In this paper, we report for the first time the use of cerium-manganese bimetallic peroxide nanoparticles (CeMnOx) as a nanocatalyst with high pH responsiveness, H2O2 self-supplying properties, multiple ROS-generating activity and synergistic effect-enhanced cascade catalytic reactions for efficient antimicrobial therapy. CeMnOx achieved more than 95% kill rate at 50 mg mL-1 for E. coli and 100 mg mL-1 for S. aureus, which was superior to those of previously reported works. To further improve the availability, nanoparticle-carrying hydrogels with excellent antimicrobial properties were prepared through in situ gelation, thus adapting to a wider range of antimicrobial application scenarios. Therefore, the in situ molded nanocatalytic antimicrobial gels provide a promising paradigm for efficient treatment of bacterial infections. [ABSTRACT FROM AUTHOR]

Epimedium is an essential genus of homologous plants used as medicine and food, which has various pharmacological effects and great utilization value in the market. Currently, research into the quality of Epimedium focuses mainly on species and region identification. However, the harvesting period also influences the quality of Epimedium; this aspect requires further study. In this paper, a systematic method is developed based on high-performance liquid chromatography (HPLC) fingerprint analysis, chemometrics, and network pharmacology methods to compare the quality of Epimedium from two harvest periods. A method is developed using liquid chromatography–mass spectrometry (LC-MS) to identify fingerprint peaks. Chemical composition analysis is performed using cluster analysis and orthogonal partial least squares discriminant analysis (OPLS-DA). Ultimately, network pharmacology analysis is employed to forecast the potential effects of compounds associated with standard chromatographic peaks. The fingerprint peaks were identified through LC-MS and corroborated with references. Subsequently, chemometric analysis revealed a distinct division between the HPLC fingerprints of samples from the two harvest periods. This was accomplished by employing cluster analysis and OPLS-DA. Additionally, utilizing the variable impact projection (VIP) obtained from OPLS-DA, a total of seven compounds exhibiting quality discrepancies were identified. Lastly, the network pharmacology analysis indicated that compounds corresponding to typical chromatographic peaks demonstrate therapeutic effects on osteoporosis. Moreover, primary bioactive compounds are identified through degree value screening. This approach is powerful for the quality assessment of Epimedium from different harvesting periods and can also be extensively applied for the quality control of other herbal materials. [ABSTRACT FROM AUTHOR]

Sensitive detection of toxic substances in drinking water is always a difficult problem in electrochemical applications. This paper presents a new electrode enhanced with nanomaterials for the sensitive detection of nitrobenzene (NB). A bimetallic Cu5Zn8 alloy was created using the copper-zeolitic imidazole framework (Cu/ZIF-8). Based on this, we synthesized a Cu5Zn8@SiO2/nitrogen-doped carbon (NC) composite. The experimental results showed that the Cu5Zn8@SiO2/NC composite has good conductivity and electron transfer ability, which was conducive to the reduction of NB. The fabricated Cu5Zn8@SiO2/NC electrode has a wide linear range with a low detection limit for the reduction of NB. At the same time, it has better anti-interference ability and reproducibility. Additionally, with good recoveries, Cu5Zn8@SiO2/NC was successfully used to monitor NB in tap water. [ABSTRACT FROM AUTHOR]

The document is a contents list for the New Journal of Chemistry, a publication by The Royal Society of Chemistry. It features papers on various topics such as boron nitride-carbon composites, organic/inorganic artificial bones, and metal-organic frameworks. The journal aims to connect the world with the chemical sciences. The document also includes corrections to previous publications. [Extracted from the article]

Metal–organic frameworks (MOFs) have unique potential in the field of gas sensing due to their ultra-high specific surface area and abundant mesoporous structure. In this paper, a mesoporous Co3O4 hollow polyhedron structure with high specific surface area (141.6 m2 g−1) was synthesized by annealing at the optimum temperature. The gas response of the mesoporous Co3O4 hollow polyhedron structure to volatile organic compounds such as xylene, ethanol, methanol and acetone was systematically tested. The experimental results show that the mesoporous Co3O4 hollow polyhedron structure has the highest sensitivity (21.33) and excellent stability for xylene gas, and the detection limit is low (1 ppm). The excellent sensing performance benefits from large surface area, high oxygen defect concentration and mesoporous structure. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (MNPs) composited on metal–organic frameworks (MOFs) can generate valuable materials (MNP/MOF) possessing good physical, chemical, and biological properties. The preparation of novel MNP/MOF followed by exploration of their applications has inspired great investigational enthusiasm. In this paper, Ni, Co and Ni–Co bimetallic MNP/MOF catalysts derived from MOFs were prepared by controlled pyrolysis, and then characterized by TGA, FTIR, XRD, BET, SEM, XPS and H2-TPD, which showed that pyrolysis under H2 (reported typically under an inert atmosphere) and the addition of Co to Ni–MOF could form Ni–Co alloy MOFs with not only a relatively complete MOFs structure but good dispersion of metal nanoparticles. In order to disclose their potential for utilization, specifically, the activity tests of the prepared novel MNP/MOF materials were conducted on the hydrogenation of toluene towards methylcyclohexane. The results confirmed that the Ni1Co2/MOF-325 catalyst obtained by pyrolysis of Ni1Co2–MOF under H2 at 325 °C had high activity and good stability for the hydrogenation of toluene, showing excellent prospect as a hydrogenation catalyst. [ABSTRACT FROM AUTHOR]

The study of catalysts supported by polyoxometalates (POMs) with green oxidative desulfurization activity is an important research topic in oil refining. In this paper, a nano-sized H-β zeolite support was modified by tetraethyl orthosilicate (TEOS) and tetrabutyl titanate (TBOT) to form a microporous–mesoporous structure. On this basis, the modified H-β zeolite was used as a support to load POMs with different structures. The characterization results of Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, scanning electron microscopy (SEM), N2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy showed that POMs had been successfully loaded onto the support, and the skeleton structures of POMs and zeolites were maintained. The introduction of POMs significantly improved the ODS performance of bulky organic sulfides, especially benzothiophene (BT). The order of catalytic oxidative desulfurization activity of POMs with different structures was: Keggin > Sandwich ≈ Anderson > monovacant Dawson > Dawson > MoO3. Under the optimum reaction conditions: T = 50 °C, t = 1 h, moil : mcatalyst = 35 : 1, and n(O) : n(S) = 13 : 1, the oxidation conversion of BT and dibenzothiophene over the catalyst supported by phosphotungstic acid (HPW) reached 99.9%. The role of titanium active species, peroxide polyoxometalate, and titanium–silicon composite oxides in improving the oxidative removal of organic sulfides was discussed. [ABSTRACT FROM AUTHOR]

In this paper, the NO donor trans-(Cl,Cl)-[Ru(FT)Cl2(NO)]Cl (Ru–NO) was incorporated in a Pluronic F127 (PL)–chitosan (CS) biocompatible hydrogel. Two concentrations were achieved (520 and 13 μg g−1), resulting in hydrogels with sol–gel transition temperatures of around 36–38 °C, according to rheological studies. The presence of the Ru–NO complex did not significantly modify the thermal (DSC) and morphological (AFM) characteristics of the gels. For Ru–NO-embedded hydrogels, nitric oxide photorelease was evidenced at 400 nm. The quantum yield of photorelease was independent of the temperature at which the gel was maintained (25, 31, or 37 °C) and was found to be ca. 0.015. EPR as well as measurements using an electrochemical NO sensor also confirmed NO release upon light irradiation at 400 nm. [ABSTRACT FROM AUTHOR]

We present in this paper the stability of SWCNT hybrid systems with Py molecules. vdW type interactions are therefore the main interaction mechanism between encapsulated molecules and nanotubes, and the simplest model to describe these interactions is the Lennard-Jones potential. We have therefore performed energy minimization calculations on hybrid SWCNTs in a very wide range of diameters and of all chirality using the Lennard-Jones potential. The structure of the carbon nanotube is obtained from the winding of graphene on itself to form a hollow cylinder described by the pair of integers (n, m) entirely determining its structural characteristics, while the optimization of the geometry of the Py molecule is obtained by SIESTA using the exchange–correlation functional LDA. After minimisation, an approach that combines density functional theory, molecular mechanics, bond polarizability model, and spectral moment's method has been used to compute Raman spectra. Two types of vibration modes of SWCNTs attract our attention. Initially, the modifications of the modes of Py after encapsulation will be analyzed. In the following discussion, we examine how the vibrational properties of single-walled carbon nanotubes (SWCNTs) are affected by encapsulation, specifically in relation to the RBM and tangential modes. Our analysis of the Raman active modes supports the notion that the structural integrity of the SWCNTs remains intact and indicates the occurrence of a charge transfer between the Py molecules and SWCNTs. This charge transfer depends on the geometric position of Py in the SWCNT. [ABSTRACT FROM AUTHOR]

In this paper, the precursors of the target product were prepared using a simple solvothermal method. After pyrolysis of the precursors, a three-dimensional Fe/CuFe2O4@C (referred to as FCC) nanomaterial with a relief texture was successfully prepared, which was employed as a novel catalyst material for activated persulfate (referred to as PS) degradation, tetracycline (referred to as TC), in wastewater. X-ray photoelectron spectroscopy (XPS) revealed that Fe(III) and Cu(II) served as the primary active metal ions, while the formation of a surface carbon shell positively influenced electron transfer during catalytic degradation. A comprehensive investigation was conducted to assess the efficiency of FCC nanocatalysts in degrading TC under various conditions. The results demonstrated that the degradation rate of TC in the 100 min range was about 96% at concentrations of 0.2 g L−1 FCC and 1 mmol L−1 persulfate and pH 7. Quenching experiment results and EPR results consistently indicated that both free radical and non-radical pathways involved in TC degradation by FCC nanomaterials, and sulfate radicals, hydroxyl radicals, superoxide radicals and singlet oxygen were identified to be the main active substances. The degradation intermediates were analyzed by liquid mass spectrometry and toxicology. FCC, as a catalyst exhibiting high catalytic activity, demonstrates superior performance in the activated persulfate degradation of TC. The environmental risk associated with the degradation of intermediate products is significantly lower than that of TC itself. FCC holds significant potential for the degradation of antibiotics in wastewater. [ABSTRACT FROM AUTHOR]

This paper reports on the photodegradation of the Rh 6G dye using a g-C3N4 (g-CN) nanosheet photocatalyst under UV light irradiation. The g-C3N4 nanosheets were synthesized using a simple pyrolysis method at 450 °C for 3 h at a heating rate of 2 °C min−1. Their structural phase, functional groups, surface area, optical properties, elemental composition, and morphology were investigated via XRD, BET, UV-vis, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, and SEM microscopy. The tri-s-triazine structure of g-C3N4 was confirmed and the crystal size was calculated to be 5 nm. g-C3N4 displayed a nanosheet morphology with a BET surface area of 8 m2 g−1. C–N stretching and s-triazine units were observed in the FTIR spectrum. The photoluminescence (PL) emission maximum at 432 nm provided band edge emission related to a band gap of 2.9 eV, and the PL lifetime was 7.6 ns, which is reasonably high for photocatalytic application. Through the C1s XPS spectrum, sp2-hybridized carbon linkages of N–C＝N in the aromatic skeleton rings, such as triazine or heptazine rings, of g-C3N4 were found. The photocatalytic characteristics of g-C3N4 were studied with the Rh-6G dye using UV light illumination. Initially, the Rh-6G dye concentration and catalyst (g-C3N4) loading were optimized for the best dye degradation at 0.01 mmol and 50 mg, respectively. The maximum efficiency of g-C3N4 was 99.6% degradation of the Rh-6G dye in 300 minutes. Lower charge-transfer resistance was found to be the reason for the enhanced photodegradation activity. The most dominant reactive species that participated in the light-activated reaction were superoxide radicals. The influence of pH on photodegradation was studied and the photocatalyst was found to perform better in an acidic pH range. In addition, g-C3N4 was structurally stable, highly recyclable, and, therefore, could be reused in many cycles of photocatalysis. [ABSTRACT FROM AUTHOR]