In-situ synthesis of g-C3N4 with nitrogen vacancy and cyano group via one-pot method for enhanced photocatalytic activity
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-06-05 |
| Journal | Scientific Reports |
| Authors | Xiang Bi, LiâZhong Wang, Ds Zhai, Lei Wang, Hui Yang |
| Institutions | Taizhou Vocational and Technical College, Shaanxi University of Science and Technology |
| Citations | 3 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Advanced Carbon Materials for Photocatalysis
Section titled âTechnical Documentation & Analysis: Advanced Carbon Materials for PhotocatalysisâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates the synthesis of defect-engineered graphitic carbon nitride (V${N}$-g-C${3}$N$_{4}$) via a simple one-pot method, achieving significant enhancement in visible-light photocatalytic activity for toxic wastewater remediation.
- Core Achievement: In-situ introduction of nitrogen vacancies (V${N}$) and cyano groups into g-C${3}$N$_{4}$ structure.
- Performance Enhancement: V${N}$-g-C${3}$N${4}$ achieved 81% Rhodamine B (RhB) degradation (1.4-fold increase) and 94.6% Acetaminophen (ACT) removal (1.6-fold increase) compared to pure g-C${3}$N$_{4}$.
- Mechanism: Defect engineering narrowed the bandgap (from 2.63 eV to 2.56 eV) and increased the BET surface area (from 27.5 to 35.7 m2g-1), providing more active sites.
- Kinetics Improvement: The defects acted as electron traps, significantly reducing the average charge carrier recombination lifetime ($\tau_{av}$) from 10.87 ns to 8.40 ns.
- Active Species: The primary active species responsible for degradation were identified as holes (h$^{+}$, 67.3%) and singlet oxygen (1O$_{2}$, 63.0%).
- 6CCVD Value Proposition: This study highlights the critical role of defect engineering and advanced carbon materials in environmental remediation. 6CCVD offers superior Boron-Doped Diamond (BDD) materials, which are the industry standard for stable, high-efficiency electrochemical and photoelectrochemical oxidation processes (AOPs).
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the characterization and performance testing of the synthesized materials (g-C${3}$N${4}$ vs. V${N}$-g-C${3}$N$_{4}$).
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Pure Material Bandgap (g-C${3}$N${4}$) | 2.63 | eV | Calculated from UV-Vis DRS |
| Defect Material Bandgap (V${N}$-g-C${3}$N$_{4}$) | 2.56 | eV | Bandgap narrowing due to V$_{N}$ introduction |
| BET Surface Area (Pure g-C${3}$N${4}$) | 27.5 | m2g-1 | Nitrogen adsorption-desorption test |
| BET Surface Area (V${N}$-g-C${3}$N$_{4}$) | 35.7 | m2g-1 | Increased active sites |
| Average Carrier Lifetime ($\tau_{av}$) (Pure g-C${3}$N${4}$) | 10.87 | ns | Time-resolved PL decay |
| Average Carrier Lifetime ($\tau_{av}$) (V${N}$-g-C${3}$N$_{4}$) | 8.40 | ns | Reduced electron-hole recombination |
| RhB Degradation Rate Constant (k) | 0.0132 | min-1 | V${N}$-g-C${3}$N$_{4}$ performance |
| ACT Removal Rate Enhancement | 1.6 | -fold | Compared to pure g-C${3}$N${4}$ in visible light |
| Conduction Band Minimum (V${N}$-g-C${3}$N$_{4}$) | -1.15 | V vs. NHE | Determined by Mott-Schottky plot intercept |
| Valence Band Position (V${N}$-g-C${3}$N$_{4}$) | 1.41 | eV | Calculated from CBM and Eg |
| Primary Active Species Contribution (h$^{+}$) | 67.3 | % | Hole contribution to degradation |
| Secondary Active Species Contribution (1O$_{2}$) | 63.0 | % | Singlet Oxygen contribution |
Key Methodologies
Section titled âKey MethodologiesâThe V${N}$-g-C${3}$N$_{4}$ catalyst was synthesized using a controlled thermal polymerization process, with atmospheric control being the key variable for defect introduction.
- Precursor Preparation: 6 g of urea and 1 mL of deionized water were fully mixed and placed in a covered crucible.
- Bulk g-C${3}$N${4}$ Synthesis (Control): Thermal polymerization conducted under air condition.
- Heating Stage 1: Heated to 100 °C at 0.5 °C/min, held for 1 h.
- Heating Stage 2: Continued heating to 500 °C at 5 °C/min, held for 2 h.
- V${N}$-g-C${3}$N$_{4}$ Synthesis (Defect Material): Identical thermal polymerization process and temperature profile, but conducted under a controlled Nitrogen (N$_{2}$) atmosphere.
- Photocatalytic Testing:
- RhB Degradation: 30 mg of catalyst mixed with 50 mL of 30 mg/L RhB solution, irradiated under a 40 W LED white lamp.
- ACT Removal: 10 mg of catalyst mixed with 50 mL of 10 mg/L ACT solution, irradiated under an 8 W LED lamp.
- Electrochemical Testing: Measurements (EIS, photocurrent, Mott-Schottky) performed using a conventional three-electrode cell with a catalyst-coated glassy carbon electrode (1 cm x 1 cm) as the working electrode, utilizing 0.2 mol L-1 Na${2}$SO${4}$ as the electrolyte.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe research demonstrates that engineering the electronic structure of carbon-based semiconductors through defect introduction (V$_{N}$ and cyano groups) is highly effective for enhancing photocatalytic performance in wastewater treatment. 6CCVD specializes in manufacturing high-purity, defect-controlled MPCVD diamond materials, offering superior stability and efficiency for advanced oxidation processes (AOPs) like those required for ACT and RhB degradation.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research into stable, industrial-scale water treatment systems, 6CCVD recommends the following materials, leveraging diamondâs unmatched electrochemical stability and wide potential window:
- Heavy Boron-Doped Diamond (BDD): Ideal for advanced electrochemical and photoelectrochemical oxidation (PEO). BDD electrodes generate high concentrations of hydroxyl radicals (â˘OH) and other powerful oxidants in situ, offering superior degradation rates and stability compared to g-C${3}$N${4}$ for persistent organic pollutants (POPs).
- Optical Grade Single Crystal Diamond (SCD): If the application requires high-power UV light (e.g., for activating certain catalysts or direct photolysis), 6CCVD offers SCD windows up to 500 Âľm thick with exceptional transparency from UV to far-IR.
Customization Potential
Section titled âCustomization PotentialâThe experimental setup utilized specific electrode dimensions (1 cm x 1 cm) and required robust electrical contacts, areas where 6CCVD provides critical customization:
| Requirement from Research | 6CCVD Customization Capability | Benefit to Client |
|---|---|---|
| Small Electrode Size (1 cm x 1 cm) | Custom Dimensions: Plates/wafers up to 125mm (PCD/BDD) and custom laser cutting services. | Enables seamless scale-up from lab-bench testing to pilot-scale reactors. |
| Need for Electrical Contact | Internal Metalization: Standard BDD electrodes can be metalized with Au, Pt, Ti, W, or Cu contacts. | Ensures robust, low-resistance electrical connections for high-current electrochemical applications. |
| Surface Morphology Control | Polishing Services: Ultra-smooth surfaces (Ra < 1nm for SCD, < 5nm for PCD/BDD). | Guarantees consistent surface area and morphology, critical for reproducible electrochemical and catalytic performance. |
| Defect Control | Doping Precision: Precise control over Boron doping levels (BDD) during MPCVD growth. | Allows researchers to tune the electronic properties (like band structure and carrier concentration) of the diamond electrode, mirroring the defect engineering strategy used in the g-C${3}$N${4}$ paper. |
Engineering Support
Section titled âEngineering SupportâThe success of the V${N}$-g-C${3}$N$_{4}$ material hinged on precise defect control to tune the band structure and carrier kinetics. 6CCVD applies similar expertise to diamond manufacturing:
- Material Selection: Our in-house PhD team provides expert consultation on selecting the optimal BDD doping concentration and morphology (SCD vs. PCD) to maximize the generation of highly oxidative species (e.g., â˘OH) for Advanced Oxidation Processes (AOPs).
- Application Expertise: We support engineers designing systems for environmental remediation, including electrochemical water treatment, ozone generation, and sensor applications, ensuring the diamond material meets the specific chemical and electrical demands of the project.
- Global Logistics: 6CCVD ensures reliable global shipping (DDU default, DDP available) for time-sensitive research and development projects worldwide.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
In-situ synthesis of g-C<sub>3</sub>N<sub>4</sub> containing nitrogen vacancies and cyano group via one-pot method using urea as the precursor. The structural, morphological or electrochemical properties of synthesized photocatalysts were characterized by XRD, BET analysis, TEM, FTIR, UV-DRS, PL, XPS and EPR. It was found that the nitrogen vacancy was successfully introduced into g-C<sub>3</sub>N<sub>4</sub>. Compared to pure g-C<sub>3</sub>N<sub>4</sub>, the (200) crystal plane in XRD of synthesized g-C<sub>3</sub>N<sub>4</sub> showed slight red-shift, and the BET surface areas had changed from 27.5 to 35.7 m<sup>2</sup>¡g<sup>-1</sup>, which could provide more reaction center and active site. TEM confirmed that g-C<sub>3</sub>N<sub>4</sub> and V<sub>N</sub>-g-C<sub>3</sub>N<sub>4</sub> were porous materials, and FTIR, XPS as well as EPR could prove the presence of nitrogen vacancies and cyano group. The UV-Vis absorption edge of V<sub>N</sub>-g-C<sub>3</sub>N<sub>4</sub> demonstrated briefly red-shift, PL intensity and lifetime of carriers declined in comparison with pure g-C<sub>3</sub>N<sub>4</sub>. Electrochemical test results showed that enhanced charge separation efficiency and low recombination rate of charge carriers of V<sub>N</sub>-g-C<sub>3</sub>N<sub>4</sub>. The photocatalytic activity of the photocatalysts was researched by RhB degradation and ACT removal under visible light irradiation, the results showed the rate of RhB degradation on the V<sub>N</sub>-g-C<sub>3</sub>N<sub>4</sub> was 81%, which was 1.4-fold as high as that of g-C<sub>3</sub>N<sub>4</sub> in visible light. The degradation contribution from the active species were h<sup>+</sup> (67.3%) ><sup>1</sup>O<sub>2</sub>(63.0%)>â˘OH (49.4%) >â˘O<sub>2</sub><sup>-</sup> (20.3%) > e<sup>-</sup> (20.1%) > H<sub>2</sub>O<sub>2</sub>(0.2%), and V<sub>N</sub>-g-C<sub>3</sub>N<sub>4</sub> exhibited excellent ACT removal rate, which was 1.6-fold higher than that of pure g-C<sub>3</sub>N<sub>4</sub> in visible light. This study provides an efficient photocatalyst for the treatment of toxic wastewater.