Compressible and Recyclable Monolithic g-C3N4/Melamine Sponge: A Facile Ultrasonic-Coating Approach and Enhanced Visible-Light Photocatalytic Activity

Transition metals-doped g-C3N4 nanostructures as advanced photocatalysts for energy and environmental applications

Graphitic carbon nitride (g-C3N4)-based heterostructured photocatalysts have received significant attention for its potential applications in the treatment of wastewater and hydrogen evolution. The utilization of semiconductor materials in heterogeneous photocatalysis has recently received great attention due to their potential and eco-friendly properties. Doping with metal ions plays a crucial role in altering the photochemical characteristics of g-C3N4, effectively enhancing photoabsorption into the visible range and thus improving the photocatalytic performance of doped photocatalysts. As an emerging nanomaterial, nanostructured g-C3N4 represents a visible light-active semiconducting photocatalyst that has attracted significant interest in the photocatalysis field, particularly for its practical water treatment applications. To the best of our knowledge, investigations of functionalized photocatalytic (PC) materials on 3d transition metal-doped g-C3N4 remain unexplored in the existing literature. g-C3N4 based heterohybrid photocatalysts have demonstrated excellent reusability, making them highly promising for wastewater treatment applications. This paper describes the overview of numerous studies conducted on the heterostructured g-C3N4 photocatalysts with various 3d metals. Research studies have revealed that the introduction of element doping with various 3d transition metals (e.g., Ti, Mn, Fe, Co, Ni, Cu, Zn, etc.) into g-C3N4 is an efficient approach to enhance degradation efficacy and boost photocatalytic activity (PCA) of doped g-C3N4 catalysts. Moreover, the significance of g-C3N4 heterostructured nanohybrids is highlighted, particularly in the context of wastewater treatment applications. The study concludes by providing insights into future perspectives in this developing area of research, with a specific focus on the degradation of various organic contaminants.

Surface modification to control the secondary pollution of photocatalytic nitric oxide removal over monolithic protonated g-C3N4/graphene oxide aerogel

Recently, photocatalytic NO_x treatment has attracted great attention on account of the use of environmental-friendly and tremendous energy source. However, the difficult recovery of most reported powdery photocatalysts and the high generation rate of toxic NO₂ byproduct limit its application. Here, we designed a novel monolithic protonated g-C₃N₄/graphene oxide aerogel through a direct frozen-drying method. A remarkable surface electric charge change of negative g-C₃N₄ to positive protonated g-C₃N₄ can be observed after the protonating treatment, which connects with negative graphene oxide nanosheets through the formation of strong electrostatic self-assembly to accelerate the photogenerated charge carriers transfer. Graphene oxide aerogel acts as a monolithic substrate, which provides abundant porous structure, enhanced visible-light absorption, and electrons transport pathway to improve photocatalytic activity. Importantly, the introduction of H atoms on the N atoms of p-C₃N₄ promotes the activation of oxygen atoms, thus improving the oxidization of NO₂ to nitrate. As a result, protonated g-C₃N₄/graphene oxide aerogel reveals an excellent NO removal ratio (46.1%) and low NO₂ generation (2.4%), demonstrating its excellent promising for air pollution purification. Our current work affords novel innovative insight for the construction of monolithic photocatalysts to control the secondary pollution for environmental remediation.

Effect of calcination temperature, pH and catalyst loading on photodegradation efficiency of urea derived graphitic carbon nitride towards methylene blue dye solution

The appropriate synthesis temperature and optimized photodegradation reaction conditions result in an appreciable enhancement of the photocatalytic activity of urea derived innate g-C₃N₄ towards MB dye degradation.

BiOCl Decorated NaNbO3 Nanocubes: A Novel p-n Heterojunction Photocatalyst With Improved Activity for Ofloxacin Degradation

BiOCl/NaNbO₃ p-n heterojunction photocatalysts with significantly improved photocatalytic performance were fabricated by a facile in-situ growth method. The obtained BiOCl/NaNbO₃ samples were characterized by UV-vis absorption spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), photocurrent (PC) and photoluminescence spectroscopy (PL). The photocatalytic activity of the BiOCl/NaNbO₃ samples was investigated by the degradation of a typical antibiotic Ofloxacin (OFX). The experimental results showed that BiOCl/NaNbO₃ composites exhibited much higher photocatalytic activity for OFX degradation compared to pure NaNbO₃ and BiOCl. The degradation percent of OFX reached 90% within 60 min, and the apparent rate constant was about 8 times as that of pure NaNbO₃ and BiOCl. The improved activity can be attributed to the formation of p-n junction between NaNbO₃ and BiOCl. The formed p-n junction facilitated the separation of photogenerated holes and electrons, thereby enhancing photocatalytic activity. In addition, the composite photocatalyst showed satisfactory stability for the degradation of OFX. Due to the simple synthesis process, high photocatalytic activity, and the good recyclability of these composite photocatalysts, the results of this study would provide a good example for the rational design of other highly efficient heterojunction photocatalytic materials.