Graphitic carbon nitride-based upconversion photocatalyst for hydrogen production and water purification

Abstract

Upconversion luminescence (UCL) is mainly a nonlinear optical method that some engineered nanomaterials can attain and helps in the transformation of low energy phonons (near-infrared photons) into higher energy phonons (ultraviolet (UV) and visible light photons). Upconversion (UC) nanomaterials are a suitable candidate for preparing near-infrared (NIR) light-responsive photocatalytic systems by mixing with other photocatalysts. Many reports have been published on lanthanide-based UC materials (Ln3+ ions as dopants) and carbon quantum dots (CQDs) carrying UC property with their use in photocatalytic removal of pollutants and energy production. Besides these UC nanomaterials, graphitic carbon nitride (g-C3N4) as a potential photocatalyst (metal-free and ecofriendly) has gained attention owing to its unique and amazing possessions. But some limitations and inadequate utilization of visible light restrict its photocatalytic applicability. Therefore, to enhance or widen its light-harvesting property towards the NIR region, the integration of upconversion nanocrystals (UC NCs) into g-C3N4 is considered an effective approach. Thus, the present review is focused on the amalgamation of g-C3N4 with UC nanomaterials for full solar spectrum absorption in H2 production and pollutant degradation via NIR light absorption.

Applications of graphitic carbon nitride-based S-scheme heterojunctions for environmental remediation and energy conversion

“…The expected photocatalytic mechanism of g-C 3 N 4 photocatalyst is presented in Fig. 1a, indicating the photocatalytic process in different steps, such as excitation of electrons in the presence of light to form photoexcited charge carriers (electrons and holes), charge carrier's migration towards the surface and finally the participation of charge carriers in further redox reactions on g-C 3 N 4 photocatalyst surface to produce ROS (Bie et al, 2021a;Sudhaik et al, 2022). Although due to constricted bandgap, g-C 3 N 4 utilize visible light and generates • O 2radicals in its CB but still can't produce • OH radicals (Sudhaik et al, 2020;Wei et al, 2021).…”

“…Henceforth, photocatalytic waste water treatment, an advanced oxidation process, has gained much consideration due to its eco-friendly features (Bie et al, 2021b). Photocatalysis technology has been extensively utilized for various energy and environmental applications (Akhundi et al, 2022;Hou et al, 2020), such as H 2 O splitting, H 2 O 2 production, CO 2 /N 2 reduction, O 2 evolution, gas purification, pollutants degradation, (Bai et al, 2022;Kudo et al, 1998;Niu et al, 2021;Sudhaik et al, 2022; etc. Photocatalytic oxidation a smart pathway, has more advantages for environmental pollutants removal.…”

“…The most commonly employed semiconductors in photocatalysis are TiO 2 , ZnO, g-C 3 N 4 , BiOCl, Ag 3 VO 4 , Fe 2 O 3 , etc. (Chen et al, 2010;Gu et al, 2016;Guo et al, 2019;Hu et al, 2007;Mishra et al, 2015;Sudhaik et al, 2022). Some of the extensively utilized wide band gap photocatalysts (TiO 2 , ZnO, etc.)…”

Synthesis and applications of carbon porous nano-materials for environmental remediation

“…Carbon-based nano-materials have been satisfactorily identified with superior implementation and tailorable effects in the adequate degradation of contaminants (Hussain et al, 2021;Kumar Mishra et al, 2021). Wherein carbon nanofibers (CNFs) have exhibited a high possibility of eradicating contaminants from water owing to their benefits of easy synthesis, chemical resilience, and economic and environmental friendliness (Kumar et al, 2022;Sudhaik et al, 2022).…”

Insight of the effect of chitosan modification on the photocatalytic properties of metal-based and metal-free photocatalysts

“…With rapid economic and industrial development, environmental pollution and energy shortages are now major worldwide issues that seriously limit sustainable human development (Ge et al, 2019;Mills et al, 1993;Sudhaik et al, 2022).…”