CeMnO₃ Nanoparticle-Decorated g-C₃N₄ Nanosheets as Z-Scheme Heterostructures for Efficient Photocatalytic Degradation of Dyes

Abstract

The design of efficient photocatalysts for dye degradation is a challenging task for the scientific community. Semiconductor-based photocatalysts such as g-C3N4 and oxides, utilizing solar energy, have been proven to be effective and promising approaches to resolve this issue to some extent. Constructing Z-scheme heterostructures by coupling g-C3N4 with suitable oxide semiconductors has shown substantial enhancement of the photocatalytic performance. In this article, perovskite-type CeMnO3 (5, 15, 25%) nanoparticle-decorated g-C3N4 nanosheets are fabricated as heterostructures, using a hydrothermal synthesis process, for efficient photocatalysis of organic dyes. The formations of heterostructures are confirmed through structural, microstructural, and elemental state analysis. Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) characterization techniques exhibited enhanced surface area and pore sizes, respectively. Ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy (DRS), Mott–Schottky, and linear sweep voltammetry (LSV) analyses along with density functional theory (DFT) calculations predicted a p–n junction heterostructure. Electron paramagnetic resonance (EPR) studies revealed a broad spectrum with sextet hyperfine lines corresponding to Mn4+ and Mn2+ ions and enhanced intensity as compared to the parent ones, signifying the creation of oxygen vacancies in the heterostructure. The CeMnO3 (25 wt %)/g-C3N4 heterostructure showed highly efficient photocatalytic degradation of methylene blue under direct sunlight irradiation, with up to 99% degradation achieved in 120 min and excellent recyclability. The robustness of this photocatalyst was tested by adopting a similar process for methylene orange dye degradation, exhibiting 94% yield in 120 min. A tentative degradation mechanism is proposed based on the enhanced photodegradation efficiency and results obtained from electrochemical impedance (EIS), photoluminescence (PL), LSV, and first principal studies, which provides more insights into the photogenerated charge separation, enhanced photocurrent, and interfacial transfer efficiency through the Z-scheme charge transfer process. This study offers opportunities for designing high-performance Z-scheme hybrid photocatalysts for environmental remediation.

Bi Quantum Dots Supported on BiOBr Nanoparticles and Loaded on Porous ZnO as a Photocatalyst for Dye Degradation and H2 Production

“…Along with human progress and the rapid development of industrial production, energy and environmental problems are increasingly serious, which even are related to human survival and development. , Since Fujishima and Honda applied TiO 2 to split water for the first time in 1972, visible light-driven semiconductor photocatalysis has been the focus of exploration by materials scientists. , Organic pollutants are usually degraded into CO 2 , H 2 O, and inorganic ions rather than converting into useful substances such as H 2 or CH 4 , which leads to the economic drain and waste of resources. , If organic pollutants can be converted into H 2 or CH 4 , it not only can reduce economic consumption but also can create new value and new energy, save resources, and achieve a win–win situation. The photocatalytic H 2 production process requires a sacrificial agent to capture h + ; if the photodegradation process of organic dyes can consume h + , the pollutants can act as a h + scavenger, and the purpose of photocatalytic H 2 production during the photodegradation of organic dyes can be achieved.…”

Toward Enhancing Photocatalytic Rate by Tunable Bandgap and Oxygen Vacancy on 2D g-C3N4/WO3–x Z-Scheme Heterojunction Nanocomposites

“…The advantages of bandgap engineering are the larger/smaller bandgap caused by the conduction band (CB) and valence band (VB) moving oppositely, together with the photophysical behavior change of the photoexcited charge carriers. , The former enhances the redox capacity of the carriers, and the latter effectively extends the carrier service time . However, a single strategy often does not make up for the shortcomings of g-C 3 N 4 …”