In situ construction of g-C3N4/g-C3N4 metal-free heterojunction for enhanced visible-light photocatalysis

Enhanced photocatalytic activity of g-C3N4–ZnO/HNT composite heterostructure photocatalysts for degradation of tetracycline under visible light irradiation

These two graphs displayed are: (1) schematic illustration on fabricating g-C₃N₄–ZnO/HNTs photocatalysts; (2) schematic diagram of the reaction mechanism for g-C₃N₄–ZnO/HNTs composite under visible light irradiation.

Synthesis of g-C3N4 at different temperatures for superior visible/UV photocatalytic performance and photoelectrochemical sensing of MB solution

The visible light absorption of g-C₃N₄ was extended through controlling the synthesis temperature, and thus enhanced visible/UV photocatalytic activity. Moreover, g-C₃N₄ can also be used as a photoelectrochemical sensor.

Construction of g-C3N4/S-g-C3N4 metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions

g-C₃N₄/S-g-C₃N₄ metal-free isotype heterojunction catalysts with an enhanced charge driving force were prepared by a two step calcination method. The results indicate that this method can lead to a more efficient charge-carrier migration.

Template synthesis of carbon self-doped g-C3N4 with enhanced visible to near-infrared absorption and photocatalytic performance

Carbon self-doped g-C₃N₄ with enhanced visible to near-infrared absorption and photocatalytic activity was synthesized by a soft-template method.

A general method for type I and type II g-C3N4/g-C3N4 metal-free isotype heterostructures with enhanced visible light photocatalysis

Composite precursors were used to construct type I and type II g-C₃N₄/g-C₃N₄ metal-free isotype heterostructures based on different band-alignment patterns.

Controlled deposition of Au on (BiO)2CO3 microspheres: the size and content of Au nanoparticles matter

Novel 3D Au/(BiO)₂CO₃ heterostructures with size-controlled Au nanoparticles (2–10 nm) were first synthesized and applied in photocatalytic NO removal.

Constructing metal-free polyimide/g-C3N4 with high photocatalytic activity under visible light irradiation

A novel metal-free polyimide (PI)/g-C₃N₄ heterojunction has been prepared, characterized and their photocatalytic performance was compared with g-C₃N₄.

Controlling interfacial contact and exposed facets for enhancing photocatalysis via 2D–2D heterostructures

The BiOIO₃/BiOI 2D–2D layered heterostructures with intimate contact and exposed reactive facets endowed the heterostructures with highly enhanced visible photocatalysis.

Quick and facile preparation of visible light-driven TiO2 photocatalyst with high absorption and photocatalytic activity

Self-doping TiO₂ has recently attracted considerable attention for its high photocatalytic activity under visible-light irradiation. However, the literature reported synthetic methods until now were very time-consuming. In this study, we establish a quick and facile method for obtaining self-doping TiO₂ with the use of directly treated commercial P25 at a desired temperature for only 5 min through spark plasma sintering technology. With the using of this method, the modified P25 samples exhibit significantly high photoelectric and photocatalytic performance. Furthermore, the sample prepared at 600°C exhibits the optimum catalytic activity. The photodegradation and H₂ evolution rates of this samples are significantly higher than those of unmodified P25 sample under visible-light irradiation. The physical origin of the visible-light absorption for the modified P25 samples is investigated in detail according to their structural, optical, and electronic properties. This work will provide a quick and facile method for the large-scale synthesis of visible-light driven photocatalyst for practical applications.

Immobilization of polymeric g-C3N4 on structured ceramic foam for efficient visible light photocatalytic air purification with real indoor illumination

The immobilization of a photocatalyst on a proper support is pivotal for practical environmental applications. In this work, graphitic carbon nitride (g-C3N4) as a rising visible light photocatalyst was first immobilized on structured Al2O3 ceramic foam by a novel in situ approach. Immobilized g-C3N4 was applied for photocatalytic removal of 600 ppb level NO in air under real indoor illumination of an energy-saving lamp. The photocatalytic activity of immobilized g-C3N4 was gradually improved as the pyrolysis temperature was increased from 450 to 600 °C. The optimized conditions for g-C3N4 immobilization on Al2O3 supports can be achieved at 600 °C for 2 h. The NO removal ratio could reach up to 77.1%, exceeding that of other types of well-known immobilized photocatalysts. Immobilized g-C3N4 was stable in activity and can be used repeatedly without deactivation. The immobilization of g-C3N4 on Al2O3 ceramic foam was found to be firm enough to overwhelm the continuous air flowing, which can be ascribed to the special chemical interaction between g-C3N4 and Al2O3. On the basis of the 5,5'-dimethyl-1-pirroline-N-oxide electron spin resonance (DMPO ESR) spin trapping and reaction intermediate monitoring, the active species produced from g-C3N4 under illumination were confirmed and the reaction mechanism of photocatalytic NO oxidation by g-C3N4 was revealed. The present work could provide new perspectives for promoting large-scale environmental applications of supported photocatalysts.

Synthesis of potassium-modified graphitic carbon nitride with high photocatalytic activity for hydrogen evolution

Potassium-modified graphitic carbon nitride (K-g-C3N4) nanosheets are synthesized by a facile KCl-template method that holds the advantage of easy removal of residual template. A combination of XRD, X-ray photoelectron spectroscopy, and inductively coupled plasma analyses are utilized to characterize the obtained resultant K-g-C3N4 architectures, which are composed of nanosheets of variable thickness (<10 nm). Photocatalytic hydrogen evolution experiments under visible light irradiation showed that K-g-C3N4 nanosheets have high photocatalytic activities (up to about thirteen times higher than that of pure g-C3 N4 ) as well as good stability (no reduction in activity within 16 h); both features emanate from their unique structural characteristics. These results illustrate the viability of this methodology for the facile synthesis of efficient heterogeneous photocatalysts for potential commercial applications.

g-C3N4-Based Photocatalysts for Hydrogen Generation

Graphitic carbon nitride (g-C3N4)-based photocatalysts have attracted dramatically increasing interest in the area of visible-light-induced photocatalytic hydrogen generation due to the unique electronic band structure and high thermal and chemical stability of g-C3N4. This Perspective summarizes the recent significant advances on designing high-performance g-C3N4-based photocatalysts for hydrogen generation under visible-light irradiation. The rational strategies such as nanostructure design, band gap engineering, dye sensitization, and heterojunction construction are described. Finally, this Perspective highlights the ongoing challenges and opportunities for the future development of g-C3N4-based photocatalysts in the exciting research area.

Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications

A biomolecule-assisted pyrolysis method has been developed to synthesize sulfur-doped graphitic carbon nitride (CNS) nanosheets. During the synthesis, sulfur could be introduced as a dopant into the lattice of carbon nitride (CN). Sulfur doping changed the texture as well as relative band positions of CN. By growing CN on preformed sulfur-doped CN nanosheets, composite CN/CNS heterojunction nanosheets were constructed, which significantly enhanced the photoelectrochemical performance as compared with various control counterparts including CN, CNS and physically mixed CN and CNS (CN+CNS). The enhanced photoelectrochemical performance of CN/CNS heterojunction nanosheets could be ascribed to the efficient separation of photoexcited charge carriers across the heterojunction interface. The strategy of designing and preparing CN/CNS heterojunction photocatalysts in this work can open up new directions for the construction of all CN-based heterojunction photocatalysts.

Facile approach to synthesize g-PAN/g-C3N4 composites with enhanced photocatalytic H2 evolution activity

Novel composites consisting of graphitized polyacrylonitrile (g-PAN) nanosheets grown on layered g-C3N4 sheets were synthesized through a facile one-step thermal condensation of PAN and melamine for the first time. Photoluminescence spectroscopy and the photoelectrochemical measurements reveal that g-PAN nanosheets act as effective electron transfer channels to facilitate charge carrier separation in g-PAN/g-C3N4 composites. The g-PAN/g-C3N4 composites exhibit significantly enhanced visible-light photocatalytic performance for H2 evolution over pristine g-C3N4. The 5.0 wt % g-PAN/g-C3N4 composite has optimal H2 evolution rate of 37 μmol h(-1), exceeding 3.8 times over pristine g-C3N4. We have proposed a possible mechanism for charge separation and transfer in the g-PAN/g-C3N4 composites to explain the enhanced photocatalytic performance.

Facile synthesis of organic–inorganic layered nanojunctions of g-C3N4/(BiO)2CO3 as efficient visible light photocatalyst

2D g-C₃N₄/(BiO)₂CO₃ organic–inorganic nanojunctions were constructed by in situ depositing (BiO)₂CO₃ nanoflakes on the surface of g-C₃N₄ nanosheets for highly active visible light photocatalysis.

High alkalinity boosts visible light driven H2 evolution activity of g-C3N4 in aqueous methanol

A high rate of 2.23 mmol h⁻¹ g⁻¹ (quantum efficiency of 6.67% at 400 nm) for visible light driven photocatalytic H₂ evolution can be achieved with g-C₃N₄ by alkalization of the solution to a pH of 13.3, due to accelerated transfer of photoholes to the sacrificial donor.