Graphitic carbon nitride (g-C3N4)-based photocatalytic materials for hydrogen evolution

Abstract

The semiconductors, such as TiO2, CdS, ZnO, BiVO4, graphene, produce good applications in photocatalytic water splitting for hydrogen production, and great progress have been made in the synthesis and modification of the materials. As a two-dimensional layered structure material, graphitic carbon nitride (g-C3N4), with the unique properties of high thermostability and chemical inertness, excellent semiconductive ability, affords good potential in photocatalytic hydrogen evolution. However, the related low efficiency of g-C3N4 with fast recombination rate of photogenerated charge carriers, limited visible-light absorption, and low surface area of prepared bulk g-C3N4, has called out the challenge issues to synthesize and modify novel g-C3N4-block photocatalyst. In this review, we have summarized several strategies to improve the photocatalytic performance of pristine g-C3N4 such as pH, morphology control, doping with metal or non-metal elements, metal deposition, constructing a heterojunction or homojunction, dye-sensitization, and so forth. The performances for photocatalytic hydrogen evolution and possible development of g-C3N4 materials are shared with the researchers interested in the relevant fields hereinto.

Recent advances in ternary Z-scheme photocatalysis on graphitic carbon nitride based photocatalysts

“…Nevertheless, practical uses of pristine g-C 3 N 4 encounter issues for instance the high-speed recombination of photoinduced electron-hole pairs, which is related to its inefficiency in the water splitting process. Consequently, research endeavors focused on boosting effectiveness of g-C 3 N 4 for water cleavage applications have witnessed continuous and concerted efforts over the past several years ( Cao et al, 2015 ; Gao et al, 2022 ). To construct Z-scheme heterojunction photocatalysts based on g-C 3 N 4 is an effective approach.…”

Highly Efficient Solar-Light-Active Ag-Decorated g-C3N4 Composite Photocatalysts for the Degradation of Methyl Orange Dye

“…The well-known semiconductor GCN material is stimulated to produce both holes and electrons when exposed to solar light. Modification of Ag enhances the photocatalytic performance of GCN through a combination of both the surface plasmon resonance (SPR) effect of Ag and the reduced recombination rate of photogenerated e − /h + pairs [ 19 ].…”

“…The well-known semiconductor GCN material is stimulated to produce both holes and electrons when exposed to solar light. Modification of Ag enhances the photocatalytic performance of GCN through a combination of both the surface plasmon resonance (SPR) effect of Ag and the reduced recombination rate of photogenerated e − /h + pairs [19]. Based on the above scavenger results, a possible photocatalytic mechanism of the MO dye under sunlight with the most active 5% AgGCN composite photocatalyst was proposed and is shown in Figure 11.…”

“…GCN has been extensively investigated as a very interesting photocatalyst due to its unique properties such as being metal-free, non-toxic, and easy to prepare, as well as having a suitable bandgap, having good chemical/physical properties, and being inexpensive [ 18 ]. Since it has low sunlight utilization efficiency and fast recombination of photo-generated e − /h + pairs, its photocatalytic activity is still low, making it difficult to use in real life [ 19 , 20 , 21 ]. In addition, various techniques such as metallic/non-metallic doping, noble metal deposition, and combination with semiconductors have been investigated to address the problem of the low optical absorption and fast recombination of photo–generated electron–hole pairs in GCN [ 22 ].…”

Strong Metal–Support Interactions in Cu(I)-Dark TiO2 Nanoscale Photocatalysts Prepared by Pulsed Laser Ablation for Hydrogen Evolution Reaction

“…4,5 There is also an increasing variety of materials used as photocatalysts (PCs) for the H 2 production. 6−8 Among the wide range of used PCs, the studies of materials based on graphene nitride (C 3 N 4 ), 9 cadmium sulfide, 10 and titanium dioxide (TiO 2 ) 11 predominate as the most successful systems for photocatalytic hydrogen production. TiO 2 is considered a classic, reference PC due to its activity, durability, photochemical stability, as well as the suitable position of the valence band (VB) and conduction band (CB) values to carry out the hydrogen evolution from an aqueous or aqueous−organic media.…”