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

Abstract

The contemporary era's top environmental problems include the lack of energy, recycling of waste resources, and water pollution. Due to the speedy growth of modern industrialization, the utilization of non-renewable sources has increased rapidly, which has caused many serious environmental and energy issues. In photocatalysis, as a proficient candidate, g-C3N4 (metal-free polymeric photocatalyst) has gained much attention due to its auspicious properties and excellent photocatalytic performance. But, regrettably, the quick recombination of photoinduced charge carriers, feeble redox ability, and inadequate visible light absorption are some major drawbacks of g-C3N4 that hamper its photocatalytic ability. Henceforth, these significant limitations can be solved by incorporating modification strategies. Among all modification techniques, the amalgamation of g-C3N4 with two or more photocatalytic semiconducting materials via heterojunction formation is more advantageous. In this review, we have discussed various modification strategies, including conventional, Z-scheme and S-scheme heterojunctions. S-scheme heterojunction is consideredan efficient and profitable charge transferal pathway due to the excellent departure and transferal of photoexcited charge carriers with outstanding redox ability. Consequently, the current review is focused on various photocatalytic applications of S-scheme-based g-C3N4 photocatalysts in pollutant degradation, H2 production, and CO2 reduction.

Recent updates on g-C3N4/ZnO-based binary and ternary heterojunction photocatalysts toward environmental remediation and energy conversion

“…Ground-breaking research by Wang and co-workers on visible-light photo-catalytic water splitting over graphitic carbon nitride (g-CN) in 2009, g-CN has received a great deal of interest. It is generally agreed that, among the numerous carbon nitrides, g-CN is the highest balanced allotrope when exposed to room temperature and humidity (Sudhaik et al, 2023). Fig.…”

Construction of 2D S‐Scheme Heterojunction Photocatalyst

“…Numerous research works focus on the hybridization of g-C 3 N 4 with oxidation photocatalysts to obtain S-scheme photocatalysts. [126,127] g-C 3 N 4 -based S-scheme photocatalysts are the largest group of 2D S-scheme photocatalysts. The abovementioned metal oxides, metal sulfides, and Bi-based photocatalysts are widely coupled with g-C 3 N 4 .…”

“…Numerous research works focus on the hybridization of g‐C 3 N 4 with oxidation photocatalysts to obtain S‐scheme photocatalysts. [ 126,127 ]…”

Fabricating carbon quantum dots of graphitic carbon nitride vis ultrasonic exfoliation for highly efficient H2O2 production

“…As a developing metal-free polymer catalyst using triazine (C 3 N 3 ) or heptazine (C 6 N 7 ) as the fundamental unit, graphitic-phase carbon nitride (g-C 3 N 4 ), exhibits tremendous potential [6] . As a polymer semiconductor with a sp 2 conjugation system, g-C 3 N 4 nanosheets offer a large specific surface area, short charge transfer distance, high solubility, good stability, and a tunable electronic structure [7] , [8] , enabling various applications in photocatalytic hydrolysis, CO 2 conversion, N 2 fixation, pollutant degradation, hydrogen evolution reaction, CO-oxidation reaction and H 2 O 2 production [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] .…”