Dopant-Induced Edge and Basal Plane Catalytic Sites on Ultrathin C₃N₄ Nanosheets for Photocatalytic Water Reduction

Abstract

The emerging carbon nitride (C3N4) offers a serious possibility for realizing a highly effective hydrogen evolution reaction (HER). However, their insufficient catalytic sites and poor conductivity hamper the HER performance. Herein, an oxygen, phosphorus dual-doped ultrathin C3N4 nanosheet (O, P-CNS) is synthesized through a two-step method without a liquid solution, including calcination under air and subsequent chemical vapor deposition (CVD) with sodium hypophosphite (NaH2PO2) in N2 atmosphere. The first thermal treatment in the air atmosphere results in the introduction of O dopant on the edge of C3N4 and the exfoliation of bulk C3N4 into ultrathin nanosheets. The following P incorporation contributes to the activation of the basal plane of C3N4 and the improvement of the intrinsic electronic conductivity, thus giving rise to the facilitated H2 generation rate. Particularly, a superior H2 generation rate of 8.7 mmol g–1 h–1 under visible light and an apparent quantum yield of 23.65% with 420 nm could be realized after the two-step dual-doping-induced calcination, further confirming the enhanced charge separation with the full activation of the edge and basal plane catalytic sites of C3N4. Our work on dual-doping-induced catalytic site activation on the edge and basal plane of C3N4 will provide more guidance in the field of designing C3N4-based photocatalysts.

Solar-driven aromatic aldehydes: green production from mandelic acid derivatives by a Co(ii)/C3N4 combined catalyst in aqueous media

“…4a ), implying the remarkable mesoporous properties of the materials. 57 As a typical porous material, the specific surface area of C 3 N 4 was 28 m 2 g −1 . As expected, the specific surface area of all the catalysts increased from 28 m 2 g −1 to 86 m 2 g −1 following the addition of 15% Co-L.…”

Multipronged Fabrication of Co3Se4 Wrapped into N‐Doped Multiwall Carbon Nanotubes Tangled Hollow Dodecahedron Framework for Overall Water Splitting under Benign Condition

“…[26] On another level, the introduction of heteroatoms into carbonaceous materials can effectively alter the electronic and chemical states due to enhanced π-bonding in carbon frameworks, which is favorable for promoting their electron donor-acceptor properties and producing more catalytically active defects. [4,28,29] Wherein, N-doped graphene and CNTs have been extensively explored. For instance, Hengyi Lu et al synthesized the N-doped carbon polyhedron decorated with CoSe 2 nanoparticles, which serves as bifunctional catalyst for overall water splitting with an outstanding catalytic activity and promising stability.…”

Growth of narrow-bandgap Cl-doped carbon nitride nanofibers on carbon nitride nanosheets for high-efficiency photocatalytic H2O2 generation

“…[31][32][33][34] Based on the above problems, a lot of methods have been employed to improve the photocatalytic performance, including defect construction, heteroatom doping, morphology optimization, etc. [35][36][37][38][39][40] For example, the photocatalytic H 2 O 2 generation activity was signicantly enhanced by constructing carbon vacancies 18 or nitrogen vacancies 19 on the surface of g-C 3 N 4 due to the improved light harvesting capacity. Heteroatom doping, for example, Fe and non-metal S, P doping, has been proved to be an effective approach to boost the photocatalytic hydrogen generation activity and pollutants degradation.…”