Sulfur-doped g-C3N4 Research Articles

Sulfur-Doped g-C3N4/Polycaprolactone Nanofibers Based Smart Sensor for 8-hydroxy-2-deoxyguanosine Biomarker Monitoring

8-Hydroxy-2′-deoxyguanosine (8-OHdG) signifies one of the primary byproducts of oxidative DNA damage, thereby being a valuable DNA biomarker. This study presents a label-free, low-cost, smart sensor that could improve evaluation, tracking, and survival rates by allowing for an early assessment of cancer. Herein, we fabricated sulfur-doped graphitic carbon nitride (S-gC₃N₄) embedded in polycaprolactone (PCL) for highly efficient monitoring of 8-OHdG, offering functional groups such as sulfur and nitrogen that facilitate strong binding against 8-OHdG. FTIR, XRD, and SEM techniques were utilized to investigate the S-gC3N4/PCL nanocomposite. Interestingly, the nanocomposite demonstrates strong electrochemical responses to the oxidation of 8-OHdG, with a detection limit of 0.24 nM across a wide dynamic concentration range (1 nM–50 μM). Additionally, it exhibits exceptional durability, selectivity, reusability, and repeatability. Additionally, the designed sensor has the potential to measure 8-OHdG levels in individuals and could be used to evaluate early cancer indicators. Furthermore, the S-gC₃N₄/PCL sensor was successfully tested to determine 8-OHdG levels in human samples.

Ag2Se nanoparticles anchored on S-g-C3N4 nanosheets towards efficient photocatalytic tetracycline hydrochloride removal and H2 generation

To improve the stability of Ag based co-catalysts and to increase the photocatalytic performance of graphitic carbon nitride (g-C3N4), Ag2Se nanoparticles were grown onto superior thin sulfur-doped g-C3N4 nanosheets which was fabricated via two-step thermal polymerization at high temperature. Ultrathin S-doped g-C3N4 nanosheets were prepared via two-step thermal polymerization using melamine and thiourea. The ratios of Ag2Se were adjusted to fabricate a series of Ag2Se/S-g-C3N4 (Ag2Se/SCN) composite samples by controlled solvothermal synthesis. S-doping plays an important role in mono-dispersion of Ag2Se nanoparticles on S-g-C3N4 nanosheets because of the control of growth sites. The photocatalytic removal of tetracycline hydrochloride test indicates that sample Ag2Se/SCN-3 with Ag2Se loading of 3 % reveals the best removal effect, in which tetracycline hydrochloride of 60 % is removed within 60 min. Photocatalytic hydrogen generation test results without co-catalyst addition demonstrate that sample Ag2Se/SCN-3 exhibits the best H2 evolution rate of 2116.35 μmol·g−1·h−1, which is 3.8 times of that of pure carbon nitride. The photocatalytic mechanism tests suggest that Schottky heterojunctions are formed in the Ag2Se/S-g-C3N4 composites. The formation of Schottky heterojunctions improved the separation efficiency of photogenerated charge carriers. The incorporation of Ag2Se nanoparticles (as the co-catalyst) on S-g-C3N4 nanosheets is the key for drastically improving the photocatalytic performance and eliminating the use of Pt co-catalyst during the photocatalytic processes.

DFT and experimental study on photocatalytic degradation of tetracycline by Sulfur-doped monolayer g-C3N4 as a peroxymonosulfate activator

Doping enhances the activation of peroxymonosulfates (PMS) by metal-free carbon materials, addressing their inherent limitations in performance. In this study, experimental and theoretical calculations are combined to carry out the study of efficient activation of PMS for tetracycline degradation based on sulfur-doped g-C3N4 (SCN) as a promising photocatalyst. Calculation of the energy band structure, electronic and optical properties by density-functional theory methods suggests that doping results in a smaller band gap, smaller bond populations, and work function, leading to a redistribution of charges and dipoles at the g-C3N4 interface with a better ability to separate photogenerated h+/e− pairs. Meanwhile, the characterization and catalyst activity measurements indicate that doping improves the photocatalytic activity, which is in agreement with the theoretical calculations. In particular, the SCN synthesized at 1:1 ratio exhibited the best catalytic activity, and the degradation efficiency of TC within 2 h could reach 89.4 %. This study provides a highly effective metal-free carbon activator for the degradation of antibiotics from wastewater by PMS.

Exploring the role of redox-active species on NiS-NiS2 incorporated sulfur-doped graphitic carbon nitride nanohybrid as a bifunctional electrocatalyst for overall water splitting

The advancement of effective and robust catalysts that can replace the precious-metal-based benchmarks for electrocatalytic overall water splitting is a highly fashionable approach to exploring sustainable energy utilization and addressing environmental issues. Herein, we demonstrate a facile single-step fabrication of NiS-NiS2 nanoparticles in situ grown on the layered porous sulfur-doped graphitic carbon nitride nanosheets (NiS-NiS2/SGCN) act as bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium.Further, an increasing the Ni precursor (fixed sulfur source) increases the formation of NiS-NiS2 on the surface of SGCN (labeled as NS-1.0, NS-2.0, and NS-3.0). Structural and morphological studies such as PXRD, XPS, FTIR, HR-TEM, etc., revealed a uniform distribution of NiS/NiS2 on the surface of S-g-C3N4 nanosheets. The OER and HER activity of NiS-NiS2/SGCN nanohybrid were significantly enhanced by increasing the affinity of accessible surface-active edge sites, interfacial contact allows effective modification of electronic structure, high structural porosity, redox-active centers of Ni2+/Ni3+, and rich in sulfur vacancy. In addition, the enhancement of the exposure of the edge sites is improved by their attachment to a sulfur-doped g-C3N4 framework. As a result, in the half-cell experiments, the NiS-NiS2/SGCN (NS-3.0) catalyst exhibited enhanced performance in both OER and HER, requiring an overpotential of 298 mV to reach 50 mA/cm2 for OER and −144 mV to reach 10 mA/cm2 for HER. Furthermore, the constructed electrolyzer using Ni-S 3.0 as the cathode and anode required a cell voltage of 1.66 V to yield 50 mA/cm2 in overall water splitting. This study may inspire the in-situ synthesis of different metal sulfides on SGCN to provide a unique interfacial approach for improving the performance of bifunctional non-precious electrocatalysts.

Unlocking the photo-Fenton potential of novel magnetically separable sulfur doped g-C3N4/CoFe2O4 Z-scheme heterojunction systems towards tetracycline removal

Unlocking the photo-Fenton potential of novel magnetically separable sulfur doped g-C3N4/CoFe2O4 Z-scheme heterojunction systems towards tetracycline removal

Sulfur-doped carbon dots and g-C3N4 composite with thermally activated delayed fluorescence for white-light illumination and anticounterfeiting

Long-lived afterglow materials have attracted considerable interest in the fields of information security and illumination. Herein, a novel carbon dot (CD)-based thermally activated delayed fluorescence (TADF) material was synthesized by embedding sulfur-doped CDs (SCDs) into a graphitic carbon nitride matrix. The formation of covalent bonds between the matrix and SCDs enhances the stabilization of the triplet state in the composite, effectively suppressing nonradiative transitions. This stabilization, coupled with the effects of sulfur doping and covalent bonding, reduces the singlet–triplet splitting energy in the composite, thereby facilitating reverse intersystem crossing and resulting in TADF emission. This composite material has been successfully employed in the development of three types of CD-based white light–emitting diodes (WLEDs) excited by blue light. These WLEDs exhibit color temperatures of 7641, 5590, and 3215 K, with CIE coordinates of (0.30, 0.29), (0.33, 0.30), and (0.42, 0.40), respectively. The corresponding values of the color rendering index are recorded as 81.86, 90.13, and 75.07. In addition, this research provides a brief demonstration of the potential of the composite in information encryption and visible-light encryption applications. Furthermore, this study contributes to the advancement of CD utilization in the WLED field, promoting the development of next-generation CD-based WLEDs with exceptional properties.

Experimental and theoretical investigation of sulfur-doped g-C3N4 nanosheets/FeCo2O4 nanorods S-scheme heterojunction for photocatalytic H2 evolution

Experimental and theoretical investigation of sulfur-doped g-C3N4 nanosheets/FeCo2O4 nanorods S-scheme heterojunction for photocatalytic H2 evolution

Sulfur-doped g-C3N4/GaN n-n heterojunction for high performance low-power blue-ultraviolet photodetector with ultra-high on/off ratio and detectivity

Polymeric graphitic carbon nitride (g-C3N4) shares a structural similarity to graphene, yet it possesses a distinctive electronic band structure, rendering it promising for photoelectric applications. However, g-C3N4 faces inherent limitations such as inadequate crystalline quality, limited conductivity, and a short lifespan of photogenerated charge carriers, all of which impede the photoelectric conversion efficiency. In this work, we introduce a two-step thermal vapor condensation method for depositing compact, crack-free sulfur-doped g-C3N4 thin films. The doped thin films exhibit reduced interlayer spacing, which leads to improved conductivity and charge transfer capabilities. These processes culminate in the creation of sulfur-doped g-C3N4/GaN thin film heterojunction blue-ultraviolet photodetectors with remarkable photodetection performance, including an ultrahigh on/off ratio of 7.3 × 107 and specific detectivity of 2.06 × 1014 Jones under a low bias of −0.4 V. Moreover, it is found that the n-n heterojunction undergoes a transition from photodiode to photoconduction behavior, attributed to the photoinduced electron trapping effects by sulfur-doped sites, which outcomes a notable gain with the responsivity as high as 581 mA/W. These findings underscore the vast potential of high-quality sulfur-doped g-C3N4 thin films for photoelectric applications.

2D/2D Schottky-type hybrid heterocatalyst comprising S-doped g-C3N4 and delaminated Ti3C2 MXene: Synergistic interplay of dual strategies for effective H2 generation and pollutant degradation

The quest for sustainable solutions to environmental pollution and energy scarcity has prompted the exploration of advanced photocatalytic materials. This study introduces an efficient 2D/2D Schottky-type hybrid heterocatalyst that combines sulfur-doped 2D g-C3N4 (SCN) with delaminated 2D Ti3C2 (TC) MXene, designed for effective H2 generation and antibiotic pollutant degradation under visible light. This hybrid system leverages the synergistic interplay of two strategies: electronic band structure engineering and conductive TC MXene cocatalyst integration, addressing the critical limitations inherent in g-C3N4. The TC-4/SCN hybrid, with its optimized TC content, exhibits exceptional photocatalytic performance, achieving an H2 production yield of 79.5 μmol over 5 h and an apparent quantum efficiency of 9.2 %. Moreover, this hybrid demonstrates significant effectiveness in degrading and mineralizing the antibiotic levofloxacin, surpassing g-C3N4, SCN, other TC/SCN hybrids, and several advanced photocatalysts previously reported. Detailed characterization and mechanistic investigations attribute the outstanding photocatalytic activity to efficient charge transfer, separation, reduced recombination rates, strong optical absorption, and a large specific surface area, all of which are facilitated by the dual strategies employed in creating the 2D/2D Schottky-type heterojunction. Furthermore, reusability tests confirmed the durability and stability of the TC-4/SCN, highlighting its practical applicability for repeated use in environmental and energy applications.

Integrated anoxic/oxic biofilm reactor and photocatalytic treatment for enhanced antibiotic removal from real wastewater matrices

The widespread occurrence of sulfamethoxazole (SMZ), one of the widely used antibiotics, in aqueous environments, poses a significant threat to ecosystem health. In this study, the combination of a biofilm-based treatment system and photocatalysis was explored for the effective removal of SMZ. Initially, sulfur-doped g-C3N4 (S-C3N4) was synthesized and then combined with Bi2O3 to improve the overall photocatalytic performance. Characterization of as-prepared photocatalysts was performed to understand the chemical structures, morphologies, and optical properties. Batch studies have shown that, at neutral pH, using 1 g/L of S-C3N4/Bi2O3 (CNBI) composite results in the removal of 87.2 % of SMZ with an initial concentration of 10 mg/L. In accordance with the scavenging study, O2–• was identified as the dominant reactive species for the degradation of SMZ. After that, the identification of SMZ degradation products was carried out, and possible degradation pathways were proposed. After obtaining the optimal dosage, continuous experimentation was conducted using a photocatalytic reactor coated with CNBI composite combined with anoxic/oxic moving bed biofilm reactor. The investigation of real municipal and hospital liquid wastes containing SMZ showed an overall total organic carbon removal of 87 % and 81 %, respectively. Economic assessment, including capital and operational expenditures and synthesis costs involved in photocatalyst material, was performed to check the feasibility of photocatalysis integrated with biological systems at large-scale treatment.

A sulfur-doped algal-like g-C3N4 photocatalyst for enhanced photocatalytic and antimicrobial properties

Graphitic carbon nitride (g-C3N4) is a non-metallic semiconductor photocatalyst which is widely used in water treatment. Improving the charge separation and transfer efficiency of g-C3N4 has been a hot research...

PtCu nanoalloy loaded on sulfur-doped porous g-C3N4 for electrocatalytic hydrogen evolution

One-step thermal decomposition yielded sulfur-doped porous g-C3N4 nanosheets, subsequently loaded with a PtCu alloy for the HER.

Efficient photo-oxidation of bisphenol a and tetracycline through sulfur-doped g-C3N4/CD heterojunctions

The synergistic effects of sulfur-doped g-C3N4 and carbon dots in nanocomposite photocatalysts were explored for the degradation of contaminants of emerging concern, particularly phenolic pollutants such as bisphenol A and tetracycline.

Sulfur-doped g-C3N4/V2C MXene Schottky junctions for superior photocatalytic H2 evolution

An advanced sulfur-doped g-C3N4/V2C MXene (SCN/V2C) Schottky junction HER photocatalyst was prepared via vacuum ball milling and subsequent annealing.

Can we reversely filtrate the catalytic membrane when treating algae-laden water?

During catalytic membrane filtration, algal cells and macromolecules in environmental aqueous conditions load on the surface of the catalytic material, leading to progressive deactivation of the catalytic membrane. Here, we synthesized catalytic membranes with outstanding water flux by anchoring catalyst (δ-MnO2 and sulfur-doped g-C3N4) on homoporous base membranes and immobilizing them by PIP-TMC interfacial polymerization. And the reverse filtration was used to pre-remove the hard-to-degrade foulings such as algal cells to enhance the degradation performance and antifouling performance of the catalyst membrane. The presence of reverse pre-filtration endowed the catalytic membrane to obtain 1.5 times higher water flux than normal filtration, reducing the contact of foulings with the catalyst and improving the catalytic efficiency and stability. Therefore, the operating conditions of the catalytic layer were optimized to obtain higher degradation rates and maintain long-term catalytic activity compared to normal filtration. Also, in the treatment of algae-laden water, reverse filtration allowed algal cells to be separated due to pore size sieving and catalytic material space, avoiding cell fragmentation and release of extracellular polymers caused by activated generated reactive oxygen species. In the catalytic removal of the refractory pollutants (APAP and SMX), the SK25 membrane was able to remove 100 % of the performance with degradation rates up to 0.36 mol·L−1·s−1. This study proposes a novel strategy for catalytic membrane filtration and promotes the application of catalytic membrane filtration technology in practical environmental problems.

Construction of Embedded Sulfur-Doped g-C3N4/BiOBr S-Scheme Heterojunction for Highly Efficient Visible Light Photocatalytic Degradation of Organic Compound Rhodamine B.

Constructing S-scheme heterojunction catalysts is a key challenge in visible-light catalysed degradation of organic pollutants. Most heterojunction materials are reported to face significant obstacles in the separation of photogenerated electron-hole pairs owing to differences in the material size and energy barriers. In this study, sulfur-doped g-C3N4 oxidative-type semiconductor materials are synthesized and then coupled with BiOBr reductive-type semiconductor to form S-g-C3N4/BiOBr S-scheme heterojunction. A strong and efficient internal electric field is established between the two materials, facilitating the separation of photogenerated electron-hole pairs. Notably,in situ XPS proved that after visible light irradiation, Bi3+ is converted into Bi(3+ɑ)+, and a large number of photogenerated holes are produced on the surface of BiOBr, which oxidized and activated H2O into •OH. •OH cooperated with •O2 - and 1O2 to attack Rhodamine B (RhB) molecules to achieve deep oxidation mineralization. The composite material is designed with a LUMO energy level higher than that of RhB, promoting the sensitization of RhB by injecting photogenerated electrons into the heterojunction, thereby enhancing the photocatalytic performance to 22.44 times that of pure g-C3N4. This study provides a new perspective on the efficient degradation of organic molecules using visible light catalysis.

Hydrothermal Synthesis and Characterization of Sulfur-doped g-C3N4/VS4 nanocomposite for efficient photocatalytic applications

Hydrothermal Synthesis and Characterization of Sulfur-doped g-C3N4/VS4 nanocomposite for efficient photocatalytic applications

A zearalenone detection based on molecularly imprinted surface plasmon resonance sensor including sulfur-doped g-C3N4/Bi2S3 nanocomposite

In present work, a zearalenone detection based on molecularly imprinted surface plasmon resonance (SPR) sensor including sulfur-doped g-C3N4/Bi2S3 (S-g-C3N4/Bi2S3) nanocomposite was presented for selective determination of zearalenone (ZEA) in rice grain samples. After S-g-C3N4/Bi2S3 nanocomposite was synthesized by calcination method with high purity and in accordance with green chemistry, ZEA imprinted SPR chip based on S-g-C3N4/Bi2S3 was prepared in presence of methacryloylamidoglutamicacid (MAGA) as monomer, ethylene glycol dimethacrylate (EGDMA) as cross linker, N,N′-azobisisobutyronitrile (AIBN) as initiator and ZEA as target molecule by using UV polymerization. Then, the spectroscopic, microscopic and electrochemical methods were used for the characterizations of the nanocomposite and the proposed ZEA imprinted SPR chip based on S-g-C3N4/Bi2S3. The SPR sensor showed a linearity towards ZEA in range of 1.0 – 10.0 ng/L with a detection limit (LOD) of 0.33 ng/L. Thus, the developed sensor's high repeatability, stability, reproducibility and selectivity provided reliable ZEA determination in rice grain samples, ensuring safe food consumption.

Sulfur-doped carbon nitride with carbon vacancies: Enhanced photocatalytic activity for degradation of tetracycline hydrochloride

This study presents a novel approach for the synthesis of sulfur-doped g-C3N4 with carbon vacancies using thioacetamide (TAA) as the sulfur source, combined with melamine under a self-generated ammonia environment in a closed crucible. The morphological properties of the modified catalyst were characterized, revealing that carbon vacancies and sulfur-doped decreased the catalyst's forbidden bandwidth, increased surface area, enhanced absorption of visible light, and improved the separation efficiency of photogenerated carriers. The modified carbon nitride demonstrates a remarkable degradation efficiency for tetracycline hydrochloride, achieving approximately 90 % degradation after 60 min of reaction time under a 5 W LED lamp, which is 3.4 times higher than that of pure carbon nitride. Furthermore, the toxicity analysis of the solution after photocatalyst degradation was evaluated with active E. coli, and no significant effect was observed. Overall, this study provides a novel approach for the structural modification of g-C3N4, resulting in enhanced photocatalytic activity.

Au induced in-situ formation of ultra-stable 1T-MoS2 on polymeric carbon nitride toward promoted photocatalytic hydrogen production

The co-catalysts engineering, especially the non-noble traditional metal dichalcogenides (MoS2), is a promising strategy in promoting photocatalytic water splitting for the green hydrogen gas production. Herein, we constructed a novel Au induced 1T-MoS2 modified S-doped-g-C3N4 (denoted as MASCN) photocatalyst. The experimental and characterizations results have showed that the sulfur doped g-C3N4 (SCN) could increase the dispersity of the Au nanoparticles (NPs) and help to improve the combination between SCN and Au NPs to promote electrical conductivity. More importantly, ultra-stable 1T-MoS2 was in situ formed within the induction of Au nanoparticles (NPs), thus providing high-density active sites and decreasing the interfacial charge transfer. As a result, the optimal sample exhibits a drastically enhanced photocatalytic hydrogen evolution rate (HER) of 4708.3 μmol/g/h, over 87-fold the rate of pure SCN (54 μmol/g/h) and appropriately 25-fold the rate of MoS2 modified SCN (denoted as MSCN) (185 μmol/g/h). The hybrids also manifest excellent stability and durability in cycle. This study highlights the construction strategy of MoS2 based co-catalyst for solar water splitting reactions and may provide insightful understandings for other photocatalytic applications.