In Situ Construction of Globe‐like Carbon Nitride as a Self‐Cocatalyst Modified Tree‐like Carbon Nitride for Drastic Improvement in Visible‐Light Photocatalytic Hydrogen Evolution

Abstract

Photogenerated carriers possess high recombination efficiency in carbon–nitrogen materials, which results in lower photocatalytic H2 evolution activity. By reviewing the literature, it was concluded that relying only on a structure‐controlled technique was insufficient to reduce the combination of photogenerated carriers without introducing a foreign material or element. Hence, bulk‐like g‐C3N4 [CN (B)], globe/strip‐like g‐C3N4 [CN (G/S)], and globe/tree‐like g‐C3N4 [CN (G/T)] were in situ obtained through a facile calcination method. Similar to platinum (Pt) as a cocatalyst, globe‐like carbon nitride as a self‐cocatalyst was found to improve the separation efficiency of photogenerated carriers effectively. Interestingly, the hollow‐tree‐branch morphology of CN (G/T) effectively transmitted photogenerated holes, which thereby enhanced the photocatalytic H2 evolution activity. The H2 production rates of CN (G/S) and CN (G/T) were almost 10.7 and 18.3 times greater, respectively, than that of CN (B) without the addition of Pt as a cocatalyst. Notably, CN (G/S) and CN (G/T) displayed considerable rates of H2 production in water relative to that shown by CN (B) (no activity) without the use of any sacrificial agent and by using Pt as a cocatalyst. CN (G/T) showed outstanding long‐term stability, as evidenced by seven cycle tests performed over 28 h. The charge separation and transfer process of the compounds were verified by photoluminescence (PL), time‐resolved PL spectroscopy, and photocurrent measurements.

Synergetic effect of C60/g‐C3N4 nanowire composites for enhanced photocatalytic H2 evolution under visible light irradiation

“…A recent report showed that interplane heterostructural graphene/g‐C 3 N 4 exhibited remarkable H 2 evolution rate under visible light, much higher than that of C 60 /g‐C 3 N 4 since the electrons rapidly migrate to the graphitic carbon domain . Another study showed the hollow tree branches in globe/tree carbon‐nitrogen photocatalysts improved the separation efficiency of photoinduced electron/hole pairs . Therefore, we speculated that C 60 nanorods may transfer electrons more efficiently than single C 60 molecule.…”

“…[45] Another study showed the hollow tree branches in globe/tree carbon-nitrogen photocatalysts improved the separation efficiency of photoinduced electron/hole pairs. [46] Therefore, we speculated that C 60 nanorods may transfer electrons more efficiently than single C 60 molecule. Fullerene nanorods with well-defined structure were formed by a liquid-liquid interfacial precipitation method.…”

2D/2D Pomelo Peel Graphene/g-C3N4/Cu in situ for Enhancing Photocatalytic H2 Production under Visible Light Irradiation

“…The mixture constantly exfoliated into released gas(CO、H2O and CO2) and collapsed, contributing to the preset temperature control program and activating agent KHCO3. Based on our previous work [50][51][52][53][54][55] , 2D/2D graphene/g-C3N4 (GS/CN) nanosheet was developed with the prepared few layered graphene nanosheets by above process and melamine in popular ways to further improve their performance of hydrogen evolution. Moreover, the influence of the graphitization temperature and the ratio between the pomelo peel and activating agent KHCO3) on the graphitization were conducted systematic research.…”

Fabrication of Tubular g‐C3N4 with N‐Defects and Extended π‐Conjugated System for Promoted Photocatalytic Hydrogen Production

“…As a class of clean and promising photocatalytic materials, graphitic carbon nitrogen (g‐C 3 N 4 ) stands out among the available semiconductors owing to its well‐known metal‐free nature, high stability, visible‐light absorption, easy preparation via cheap materials and so on ,. It has a broad range of potential applications in the fields of photocatalytic degradation of organic pollutants,, CO 2 reduction,, and energy conversion . Nevertheless, the pristine g‐C 3 N 4 suffers from main weakness of regarding of its low surface area, poor response to visible light and massive photoinduced charge carriers’ recombination, which depresses the photocatalysis.…”