Organic–inorganic Z-scheme g-C3N4-NiTi-layered double hydroxide films for photocatalytic applications in a fixed-bed reactor

A split-type photoelectrochemical immunosensing platform based on atom-efficient cation exchange for physiological monitoring

Ultrasensitive and accurate physiological monitoring is of great significance for disease diagnosis and treatment. In this project, an efficient photoelectrochemical (PEC) split-type sensor on the basis of controlled release strategy was established with great success. Heterojunction formation between g-C₃N₄ and Zn-doped CdS improved the visible light absorption efficiency, reduced carrier complexation, improved the PEC signal, and increased the stability of the PEC platform. Compared to the traditional model of immunosensors, the process of antigen-antibody specific binding was done in a 96 microplate, and the sensor separated the immune reaction from the photoelectrochemical conversion process, eliminating mutual interference. Cu₂O nanocubes were used to label the second antibody (Ab₂), and acid etching using HNO₃ released a large amount of divalent copper ions, which exchanged cations with Cd²⁺ in the substrate material, causing a sharp drop in photocurrent and improving the sensitivity of the sensor. Under the optimized experimental conditions, the PEC sensor based on the controlled release strategy for CYFRA21-1 target detection had a wide concentration linear range of 5 × 10^-5 to 100 ng/mL with a low detection limit of 0.0167 pg/mL (S/N = 3). This intelligent response variation pattern could also offer the possibility of additional clinical applications for other target detection.

Synthesis and applications of graphitic carbon nitride (g-C3N4) based membranes for wastewater treatment: A critical review

Semiconducting membrane combined with nanomaterials is an auspicious combination that may successfully eliminate diverse waste products from water while consuming little energy and reducing pollution. Creating an inexpensive, steady, flexible, and diversified business material for membrane production is a critical challenge in membrane technology development. Because of its unusual structure and high catalytic activity, graphitic carbon nitride (g-C3N4) has come out as a viable material for membranes. Furthermore, their great durability, high permanency under challenging environments, and long-term use without decrease in flux are significant advantages. The advanced material techniques used to manage the molecular assembly of g-C3N4 for separation membrane were detailed in this review work. The progress in using g-C3N4-based membranes for water treatment has been detailed in this presentation. The review delivers an updated description of g-C3N4 based membranes and their separation functions and new ideas for future enhancements/adjustments to address their weaknesses in real-world situations. Finally, the ongoing problems and promising future research directions for g-C3N4-based membranes are discussed.

A review on graphitic carbon nitride (g-C3N4) based hybrid membranes for water and wastewater treatment

Graphitic carbon nitride (g-C₃N₄) has gained enormous attention for water and wastewater treatment. Compared with g-C₃N₄ nanopowders, g-C₃N₄ based hybrid membranes have demonstrated great potential for its superior practicability. This review outlines the preparation and characterization of g-C₃N₄ based hybrid membranes and presents their representative applications in water and wastewater treatment (e.g., removal of organic dyes, phenolic compounds, pharmaceuticals, salt ions, heavy metals, and oils). Meanwhile, g-C₃N₄ based films for the removal of contaminants through photocatalytic degradation is also summarized. In addition, the corresponding mechanisms and relevant findings are discussed. Finally, the challenges and research needs in the future and application of g-C₃N₄ based hybrid membranes are highlighted.

Dielectric barrier discharge plasma-assisted modification of g-C3N4/Ag2O/TiO2-NRs composite enhanced photoelectrocatalytic activity

Dielectric barrier discharge (DBD) plasma applied as surface treatment technology was employed for the modification of Ag₂O and graphitic carbon nitride (g-C₃N₄) powders. Subsequently, the pretreated powders were sequentially loaded onto TiO₂ nanorods (TiO₂-NRs) via electro-deposition, followed by calcination at N₂ atmosphere. The results indicated that at the optimal plasma discharge time of 5 min for modification of g-C₃N₄ and Ag₂O, photocurrent density of ternary composite was 6 times to bare TiO₂-NRs under UV-visible light irradiation. Phenol was degraded by using DBD plasma-modified g-C₃N₄/Ag₂O/TiO₂-NRs electrode to analyze the photoelectrocatalytic performance. The removal rate of phenol for g-C₃N₄-5/Ag₂O-5/TiO₂-NRs electrode was about 3.07 times to that for TiO₂-NRs electrode. During active species scavengers' analysis, superoxide radicals and hydroxyl radicals were the main oxidation active species for pollutants degradation. A possible electron-hole separation and transfer mechanism of ternary composite with high photoelectrocatalytic performance was proposed.

Visible light driven reduced graphene oxide supported ZnMgAl LTH/ZnO/g-C3N4 nanohybrid photocatalyst with notable two-dimension formation for enhanced photocatalytic activity towards organic dye degradation

In this study, 2D/2D/2D heterostructured r-GO/LTH/ZnO/g-C₃N₄ nanohybrid were synthesized through hydrothermal method. The strong electrostatic interaction between the negatively charged g-C₃N₄ and r-GO nanosheets with positively charged layered triple hydroxide (LTH) nanosheets are effectively influences the successful formation of heterojunction. The LTH nanosheets are well spread on the g-C₃N₄ nanosheets combined with r-GO. In particular, the as prepared heterojunction shows a better photocatalytic degradation activity compared to pristine samples and the significant enhancement in the photocatalytic performance is mainly accredited to the large interfacial charge transition of photogenerated charge carriers under the visible light irradiation. Although the 2D/2D/2D heterojunction effectively hinders the charge carrier recombination resulting high photocatalytic activity with good stability. In addition, the r-GO supported LTH/ZnO/g-C₃N₄ heterojunction shows high photo-stability after sequential experimental runs with no obvious change in the dye degradation process. Consequently, the role of active species was investigated over the r-GO/LTH/ZnO/g-C₃N₄ heterojunction with the help of different scavengers.

Thin NiFeCr-LDHs nanosheets promoted by g-C3N4: a highly active electrocatalyst for oxygen evolution reaction

NiFeCr layered double hydroxides (NiFeCr-LDHs) supported on graphitic carbon nitride (g-C₃N₄) hybrids (NiFeCr-LDHs/g-C₃N₄) are synthesized and used as an electrocatalyst for oxygen evolution reaction (OER) in alkaline media. Effect of g-C₃N₄ on the structure and OER performance of NiFeCr-LDHs are investigated in detail. g-C₃N₄ can promote the formation of thin NiFeCr-LDHs nanosheets, thereby enhancing both the number of active sites and OER activity. X-ray photoelectron spectra measurements confirm the electronic interaction between g-C₃N₄ and NiFeCr-LDHs nanosheets. The OER performance of NiFeCr-LDHs/g-C₃N₄ hybrids highly relates to the weight ratio of g-C₃N₄ to NiFeCr-LDHs. When the weight ratio of g-C₃N₄ to NiFeCr-LDHs is 5%, the corresponding electrocatalyst shows the best OER activity. The component optimized NiFeCr-LDHs/g-C₃N₄ hybrids display the overpotential of ∼223 mV at 10 mA cm^-2 and Tafel slope of 89 mV dec^-1 for OER in 1 M KOH solution, which is better than that of pristine NiFeCr-LDHs, bare g-C₃N₄, and commercial RuO₂.

Powerful combination of g-C3N4 and LDHs for enhanced photocatalytic performance: A review of strategy, synthesis, and applications

The utilization of solar energy with photocatalytic technology has been considered a good solution to alleviate environmental pollution and energy shortage. Constructing 2D/2D heterostructure photocatalysts with layered double hydroxide (LDH) and graphitic carbon nitride (g-C₃N₄) is an effective approach to attain high performance in solar photocatalysis. This paper provides a review of recent studies about 2D/2D LDH/g-C₃N₄ heterostructure photocatalysts. Main strategies for constructing the desired 2D/2D heterojunction are summarized. The planar structure of LDH and g-C₃N₄ offers a shorter transfer distance for charge carriers and reduces electron-hole recombination in the bulk phase. The face-to-face contact between the two materials can promote the charge transfer across the heterostructure interface, thus improving the electron-hole separation efficiency. The performance and mechanisms of LDH/g-C₃N₄ photocatalysts in hydrogen production, CO₂ reduction, and organic pollutant degradation are analyzed and discussed. Incorporating reduced graphene oxide or Ag nanoparticles into LDH/g-C₃N₄ heterojunction and fabricating calcined LDH/g-C₃N₄ composites are effective strategies to further facilitate charge transfer at the interface of LDH and g-C₃N₄ and improve the absorption capacity for visible light. This review is expected to provide basic insights into the design of 2D/2D LDH/g-C₃N₄ heterojunctions and their applications in solar photocatalysis.