N4 Photocatalyst Research Articles

Magnetically recoverable sol-gel auto-combustion developed Ni1-xCuxDyyFe2-yO4 magnetic nanoparticles for photocatalytic, electrocatalytic, and antibacterial applications

Copper and dysprosium doped NiFe2O4 magnetic nanomaterials, Ni1-xCuxDyyFe2-yO4 (x = y = 0.00, 0.01, 0.02, 0.03), was prepared by utilizing sol-gel auto-combustion approach to inspect the photodegradation of methylene blue (MB) pollutant and also, to perform the electrocatalytic water splitting and antibacterial studies. The XRD analysis reveal the growth of a single-phase spinel cubic structure for produced nanomaterials. The magnetic traits show an increasing trend in saturation magnetization (Ms) from 40.71 to 47.90 emu/g along with a decreasing behaviour of coercivity from 158.09 to 156.34 Oe at lower and higher Cu and Dy doping content (x = 0.0–0.01). The study of optical band gap values of copper and dysprosium-doped nickel nanomaterials decreased from 1.71 to 1.52 eV. This will increase the photocatalytic degradation of methylene blue pollutant from 88.57% to 93.67% under natural sunlight, respectively. These findings clearly show that under natural sunlight irradiation for 60 min, the produced N4 photocatalyst displays the greatest photocatalytic activity with a maximum removal percentage of 93.67%. The electrocatalytic characteristics of produced magnetic nanomaterials for both HER and OER were examined with a Calomel electrode taking as a reference in a 0.5 N H2SO4 and 0.1 N KOH electrolyte. The N4 electrode demonstrated considerable 10 and 0.024 mA/cm2 of current density, with onset potentials of 0.99 and 1.5 V for HER and OER and also, have tafel slopes of 58.04 and 295 mV/dec, respectively. The antibacterial activity for produced magnetic nanomaterials was examined against various bacteria (Bacillus subtilis, Staphylococcus aureus, S. typhi, and P. aeruginosa) in which N3 sample produced significant inhibition zone against gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) but no zone of inhibition against gram-negative bacteria (S. typhi and P. aeruginosa). With all these superior traits, the produced magnetic nanomaterials are highly valuable for the wastewater remediation, hydrogen evolution, and biological applications.

One-Pot Synthesis of 2D-2D WO3 /g-C3 N4 Photocatalyst in Reverse Microemulsion System via Supercritical CO2 for Enhanced Hydrogen Generation.

Construction of Z-scheme photocatalyst is an effective approach for using solar energy to produce hydrogen during water splitting. Herein, 2D/2D WO3 /g-C3 N4 heterojunction photocatalyst was synthesized by a convenient and green method including exfoliation and heterojunction procedures, in the reverse microemulsion system via supercritical carbon dioxide (scCO2 ). The resultant W/CN-10.3 composite exhibited enhanced photocatalytic activities towards the hydrogen evolution during water splitting with a hydrogen evolution rate of 688.51 μmol g-1 h-1 , which was more than 16 times higher than bulk g-C3 N4 with the same loading amount of Pt as cocatalyst. Due to its effective separation of photogenerated carriers and prolonged lifetime, more photoexcited electrons with high reduction ability could contribute to the production of H2 . Possible formation mechanism of 2D-2D WO3 /g-C3 N4 nanosheets via scCO2 in the reverse microemulsion system by the one-pot method has been proposed. This work provides an efficient and green strategy to synthesize 2D-2D heterojunction for the utilization in solar-to-fuel conversion.

Oxygenated Triazine-Heptazine Heterostructure Creates an Enormous Ascension to the Visible Light Photocatalytic Hydrogen Evolution Performance of Porous C3 N4 Nanosheets.

A highly efficient g-C3 N4 photocatalyst is developed by a novel one-pot thermal polymerization method under a salt fog environment generated by heating the aqueous solution of urea and mixed metal salts of NaCl/KCl, namely SF-CN. Thanks to the synergistic effect of the oxygenation and chemical etching of the salt fog, the obtained SF-CN is an oxygenated ultrathin porous carbon nitride with an intermolecular triazine-heptazine heterostructure, meanwhile, shows enlarged specific surface area, greatly enhanced absorption of visible light, narrowed band gap with a lower conduction band, and an increased photocurrent response due to the effective separation of photogenerated holes and electrons, comparing to those of pristine g-C3 N4 . The theoretical simulations further reveal that the triazine-heptazine heterostructure possesses better photocatalytic hydrogen evolution (PHE) capability than pure triazine and heptazine carbon nitrides. In turn, SF-CN demonstrates an excellent visible light PHE rate of 18.13mmolh-1 g-1 , up to 259.00 times of that of pristine g-C3 N4 .

Exceptional Cocatalyst-Free Photo-Enhanced Piezocatalytic Hydrogen Evolution of Carbon Nitride Nanosheets from Strong In-Plane Polarization.

Utilizing mechanical energy to produce hydrogen is emerging as a promising way to generate renewable energy, but is challenged by low efficiency and scanty cognition. In this work, graphitic carbon nitride (g-C3 N4 ) with an atomically thin sheet-like structure is applied for prominent piezocatalytic and photo-enhanced piezocatalytic H2 production. It is revealed that the anomalous piezoelectricity in g-C3 N4 originates from the strong in-plane polarization along the a-axis, contributed by the superimposed polar tri-s-triazine units and flexoelectric effect derived from the structured triangular cavities, which provides powerful electrochemical driving force for the water reduction reaction. Furthermore, the photo-enhanced charge transfer enables g-C3 N4 nanosheets to reserve more energized polarization charges to fully participate in the reaction at the surface reactive sites enriched by strain-induced carbon vacancies. Without any cocatalysts, an exceptional photo-piezocatalytic H2 evolution rate of 12.16 mmol g-1 h-1 is delivered by the g-C3 N4 nanosheets, far exceeding that of previously reported piezocatalysts and g-C3 N4 photocatalysts. Further, high pure-water-splitting performance with production of the value-added oxidation product H2 O2 via photo-piezocatalysis is also disclosed. This work not only exposes the potential of g-C3 N4 as a piezo-semiconductor for catalytic H2 evolution, but also breaks a new ground for the conversion of solar and mechanical energy by photomediated piezocatalytic reaction.

Enhanced photocatalytic degradation activity of Z-scheme heterojunction BiVO4 /Cu/g-C3 N4 under visible light irradiation.

A novel BiVO4 /Cu/g-C3 N4 heterostructure photocatalyst was synthesized by thermal condensation, hydrothermal, and in situ precipitation method. The microscopic morphology and chemical composition of the synthesized samples were analyzed by XRD, SEM, FT-IR, XPS, and other characterizations. BiVO4 /Cu/g-C3 N4 (BiVO4 /Cu:g-C3 N4 mass ratio was 1:1) photocatalyst had the optimal photocatalytic degradation activity for tetracycline (TC) wastewater under visible light irradiation (120min, 74.8%). The introduction of Cu and Z-scheme heterojunction was further confirmed by UV-vis, PL, EIS, and capture mechanism analysis, which effectively accelerated the separation and transfer rate of photogenerated electron holes and enhanced the strong oxidation of h+ and •O2 - active species. BiVO4 /Cu/g-C3 N4 heterojunction photocatalytic material has potential application value in the removal of refractory pollutants in wastewater. PRACTITIONER POINTS: A novel Z-scheme BiVO4 /Cu/g-C3 N4 photocatalyst with excellent photocatalytic activities and stability was prepared to treat tetracycline (TC) wastewater. 1:1 CBCN (BiVO4 /Cu:g-C3 N4 mass ratio was 1:1) photocatalyst exhibited the highest photocatalytic performance for TC wastewater. The Z-scheme heterojunction and Cu act as the interfacial charge transfer medium accelerated the transfer and separation of carriers.

Improved Hg2+ photocatalytic reduction over g-C3N4 nanosheets decorated with mesoporous Mn3O4 nanoparticles

The purpose of this investigation was to construct amended mesoporous Mn3O4/g-C3 N4 photocatalysts of various loadings of mesoporous Mn3O4 nanoparticles (1,2,3 and 4 wt%) for reinforced remediation of mercury ions (Hg2+) under visible light illumination. It was performed via decorating g-C3N4 nanosheets with finite portions of the prepared mesoporous Mn3O4 NPs by employing hard and soft templates. The optimized 3 wt% Mn3O4/g-C3N4 heterojunction gained confined bandgap (2.24 eV) as well as great surface area (140 m2 g -1) that support the application of such heterojunction for efficacious removal of Hg2+ under visible light. Morphological examination elucidated that the dispersed Mn3O4 NPs over g-C3N4 nanosheets were of spherical shape with particle dimension of 10-15 nm. Hg2+ was removed significantly over the formed Mn3O4/g-C3N4 nanocomposites when related to the pure materials (Mn3O4 NPs and g-C3N4). It was confirmed that Mn3O4 content, incorporated to g-C3N4 nanosheets, largely influenced the efficiency corresponding to the Hg2+ photoreduction such that appropriating 3 wt% Mn3O4 was capable of accomplishing complete removal of Hg2+ whereas, pure g-C3N 4was able to accomplish the same process by the efficiency of 15% after illumination for 60 min. Similarly, fast rate of Hg2+ photoreduction was accessed when 3% Mn3O4/g-C3N4 nanocomposite (485 µmol g–1 h–1) was administered while the photoreduction reaction was very slow with smaller rate magnitudes when pure g-C3N 4(82 µmol g -1 h -1) or pure Mn3O4 NPs (120 µmol g -1 h -1) were adopted. The powerful Hg2+ removal over the established heterojunctions can basically be associated with the larger attained surface area as well as the declined bandgap. Besides, the great dispersion of the small-sized Mn3O4 NPs and the mesoporous structure of the formed heterojunctions participated significantly in efficient Hg2+ removal. The improved characteristics of the prepared heterojunctions led to strong absorption of visible light and fast transference of reactant species, leading to enhanced photocatalytic efficiency. Recyclability experiments demonstrated that neither the photocatalytic performance nor the structure of the mesoporous Mn3O4/g-C3N4 heterojunction was altered after being reused for Hg2+ removal from aqueous solutions.

Carbon-Graphitic Carbon Nitride Hybrids for Heterogeneous Photocatalysis.

Polymeric graphitic carbon nitride (g-C3 N4 ) and various carbon materials have experienced a renaissance as viable alternates in photocatalysis due to their captivating metal-free features, favorable photoelectric properties, and economic adaptabilities. Although numerous efforts have focused on the integration of both materials with optimized photocatalytic performance in recent years, the direct parameters for this emerging enhancement are not fully summarized yet. Fully understanding the synergistic effects between g-C3 N4 and carbon materials on photocatalytic action is vital to further development of metal-free semiconductors in future studies. Here, recent advances of carbon/g-C3 N4 hybrids on various photocatalytic applications are reviewed. The dominant governing factors by inducing carbon into g-C3 N4 photocatalysts with involving photocatalytic mechanism are highlighted. Five typical carbon-induced enhancement effects are mainly discussed here, i.e., local electric modification, band structure tailoring, multiple charge carrier activation, chemical group functionalization, and abundant surface-modified engineering. Photocatalytic performance of carbon-induced g-C3 N4 photocatalysts for addressing directly both the renewable energy storage and environmental remediation is also summarized. Finally, perspectives and ongoing challenges encountered in the development of metal-free carbon-induced g-C3 N4 photocatalysts are presented.

Potassium-Ion-Assisted Regeneration of Active Cyano Groups in Carbon Nitride Nanoribbons: Visible-Light-Driven Photocatalytic Nitrogen Reduction.

As a metal-free nitrogen reduction reaction (NRR) photocatalyst, g-C3 N4 is available from a scalable synthesis at low cost. Importantly, it can be readily functionalized to enhance photocatalytic activities. However, the use of g-C3 N4 -based photocatalysts for the NRR has been questioned because of the elusive mechanism and the involvement of N defects. This work reports the synthesis of a g-C3 N4 photocatalyst modified with cyano groups and intercalated K+ (mCNN), possessing extended visible-light harvesting capacity and superior photocatalytic NRR activity (NH3 yield: 3.42 mmol g-1 h-1 ). Experimental and theoretical studies suggest that the -C≡N in mCNN can be regenerated through a pathway analogous to Mars van Krevelen process with the aid of the intercalated K+ . The results confirm that the regeneration of the cyano group not only enhances photocatalytic activity and sustains the catalytic cycle, but also stabilizes the photocatalyst.

Oxygen-Functionalized and Ni+x (x=2, 3)-Coordinated Graphitic Carbon Nitride Nanosheets with Long-Life Deep-Trap States and their Direct Solar-Light-Driven Hydrogen Evolution Activity.

Graphitic carbon nitride, a 2 D layered photocatalyst coupled with transition metal oxides often shows promising photocatalytic hydrogen evolution activity. However, low surface area and poor charge separation greatly hinder its photocatalytic efficiency. A Ni+x (x=2, 3)/O-g-C3 N4 photocatalyst with a very high specific surface area (199 m2 g-1 ) has been prepared by thermal condensation and wet-impregnation methods. The oxygen-functionalized and Ni+x (x=2, 3)-coordinated g-C3 N4 produced 1664 μmol g-1 of hydrogen evolution from water under direct solar light irradiation in 4 h, which is 23 times higher than that over O-g-C3 N4 . This significant enhancement results from the combined effects of large surface area, the formation of long-life deep-trap states, effective charge carrier separation, and extended visible light absorption. The separation and transport behavior of the charge carriers are investigated by photoluminescence, time-resolved photoluminescence, photocurrent and Mott-Schottky measurements. Additionally, the interaction between Ni+x (x=2, 3) and O-g-C3 N4 is studied by X-ray photoelectron spectroscopy, X-ray diffraction, and FTIR spectroscopy. The Ni+x (x=2, 3)/O-g-C3 N4 photocatalyst shows remarkable reusability over a period of two months (six cycles). This study may provide a pathway to simultaneously overcome the challenges of low surface area and poor charge separation in g-C3 N4 -based photocatalysts.

Advantageous Interfacial Effects of AgPd/g-C3 N4 for Photocatalytic Hydrogen Evolution: Electronic Structure and H2 O Dissociation.

Bimetallic AgPd nanoparticles have been synthesized before, but the interfacial electronic effects of AgPd on the photocatalytic performance have been investigated less. In this work, the results of hydrogen evolution suggest that the bimetallic AgPd/g-C3 N4 sample has superior activity to Ag/g-C3 N4 and Pd/g-C3 N4 photocatalysts. The UV/Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, CO adsorption diffuse reflectance FTIR spectroscopy, and FTIR results demonstrate that in the AgPd/g-C3 N4 , the surface electronic structures of Pd and Ag are changed, which is beneficial for faster photogenerated electron transfer and greater H2 O molecule adsorption. In situ ESR spectra suggest that, under visible light irradiation, there is more H2 O dissociation to radical species on the AgPd/g-C3 N4 photocatalyst. Furthermore, DFT calculations confirm the interfacial electronic effects of AgPd/g-C3 N4 , that is, Pdδ- ⋅⋅⋅Agδ+ , and the activation energy of H2 O molecule dissociation on AgPd/g-C3 N4 is the lowest, which is the main contributor to the enhanced photocatalytic H2 evolution.

Cost-Efficient Graphitic Carbon Nitride as an Effective Photocatalyst for Antibiotic Degradation: An Insight into the Effects of Different Precursors and Coexisting Ions, and Photocatalytic Mechanism.

In this study, the photocatalytic activity of graphitic carbon nitride (g-C3 N4 ) synthesized via different precursors (urea, thiourea, and dicyandiamide) is investigated in the degradation process of tetracycline. Owing to the efficient charge separation and transfer, prolonged radiative lifetime of charge, large surface area, and nanosheet morphology, the urea-derived g-C3 N4 exhibits superior photocatalytic activity for tetracycline degradation under visible-light irradiation. This performance can compare with that of most reported g-C3 N4 -based composite photocatalysts. Through the time-circle degradation experiment, the urea-derived g-C3 N4 is found to have an excellent photocatalytic stability. The presence of NO3 - , CH3 COO- , Cl- and SO4 2- ions with the concentration of 10 mm inhibits the photocatalytic activity of urea-derived g-C3 N4 , where this inhibitory effect is more obvious for Cl- and SO4 2- ions. For the coexisting Cu2+ , Ca2+ , and Zn2+ ions, the Cu2+ ion exhibits a significantly higher inhibitory effect than Ca2+ and Zn2+ ions for tetracycline degradation. However, both the inhibitory and facilitating effects are observed in the presence of Fe3+ ion with different concentration. The h+ , . OH and . O2 - radicals are confirmed as major oxidation species and a possible photocatalytic mechanism is proposed in a urea-derived g-C3 N4 reaction system. This study is of important significance to promote the large-scale application of g-C3 N4 photocatalysts in antibiotic wastewater purification.

Tetracycline Removal Under Solar Illumination Over Ag3VO4/mpg‐C3N4 Heterojunction Photocatalysts

Ag3 VO4 /mpg-C3 N4 (mesoporous graphitic carbon nitride) heterojunction photocatalysts were prepared by anchoring tiny Ag3 VO4 particles on the nanosheet of mpg-C3 N4 . The prepared Ag3 VO4 /mpg-C3 N4 heterojunctions were used to remove tetracycline (TC), a kind of antibiotics widely released into the aquatic environment under solar irradiation. Compared with pure mpg-C3 N4 and Ag3 VO4 , Ag3 VO4 /mpg-C3 N4 displayed much higher photocatalytic activity (83.2% removal rate within 90 min under visible-light irradiation). Importantly, no apparent deactivation was observed for Ag3 VO4 /mpg-C3 N4 -40 after five cycles, inferring a good reusability. As confirmed by photocurrent measurement and photoluminescence spectra, the excellent photocatalytic property of Ag3 VO4 /mpg-C3 N4 was credit to the electron-hole separation enhancement at the formed heterojunction of two semiconductors. In addition, a possible mechanism and intermediate products for the Ag3 VO4 /mpg-C3 N4 photocatalysts toward the photodegradation of TC in aqueous solution under artificial sunlight radiation were proposed based on the scavengers trapping test, ESR spectra and a high-performance liquid chromatography (HPLC) coupled with mass spectrometer (MS) analysis. This investigation provides a low cost, green and easily practical approach to remove the antibiotics in the aquatic environment.

Metal-Free 2D/2D Phosphorene/g-C3 N4 Van der Waals Heterojunction for Highly Enhanced Visible-Light Photocatalytic H2 Production.

The generation of green hydrogen (H2 ) energy using sunlight is of great significance to solve the worldwide energy and environmental issues. Particularly, photocatalytic H2 production is a highly promising strategy for solar-to-H2 conversion. Recently, various heterostructured photocatalysts with high efficiency and good stability have been fabricated. Among them, 2D/2D van der Waals (VDW) heterojunctions have received tremendous attention, since this architecture can promote the interfacial charge separation and transfer and provide massive reactive centers. On the other hand, currently, most photocatalysts are composed of metal elements with high cost, limited reserves, and hazardous environmental impact. Hence, the development of metal-free photocatalysts is desirable. Here, a novel 2D/2D VDW heterostructure of metal-free phosphorene/graphitic carbon nitride (g-C3 N4 ) is fabricated. The phosphorene/g-C3 N4 nanocomposite shows an enhanced visible-light photocatalytic H2 production activity of 571 µmol h-1 g-1 in 18 v% lactic acid aqueous solution. This improved performance arises from the intimate electronic coupling at the 2D/2D interface, corroborated by the advanced characterizations techniques, e.g., synchrotron-based X-ray absorption near-edge structure, and theoretical calculations. This work not only reports a new metal-free phosphorene/g-C3 N4 photocatalyst but also sheds lights on the design and fabrication of 2D/2D VDW heterojunction for applications in catalysis, electronics, and optoelectronics.

Photoassisted Construction of Holey Defective g-C3 N4 Photocatalysts for Efficient Visible-Light-Driven H2 O2 Production.

Holey defective g-C3 N4 photocatalysts, which are easily prepared via a novel photoassisted heating process, are reported. The photoassisted treatment not only helps to create abundant holes, endowing g-C3 N4 with more exposed catalytic active sites and crossplane diffusion channels to shorten the diffusion distance of both reactants from the surface to bulk and charge carriers from the bulk to surface, but also introduces nitrogen vacancies in the tri-s-triazine repeating units of g-C3 N4 , inducing the narrowing of intrinsic bandgap and the formation of defect states within bandgap to extend the visible-light absorption range and suppress the radiative electron-hole recombination. As a result, the holey defective g-C3 N4 photocatalysts show much higher photocatalytic activity for H2 O2 production with optimized enhancement up to ten times higher than pristine bulk g-C3 N4 . The newly developed synthetic strategy adopted here enables the sufficient utilization of solar energy and shows rather promising for the modification of other materials for efficient energy-related applications.

Reduced Oxygenated g-C3 N4 with Abundant Nitrogen Vacancies for Visible-Light Photocatalytic Applications.

A novel g-C3 N4 photocatalyst (RCNO) with abundant nitrogen vacancies and oxygen-containing electron-withdrawing groups was prepared. Oxygen was gradually introduced into the g-C3 N4 structure by a hydrothermal hydrolysis/condensation process, and nitrogen vacancies were produced with H2 reduction. The presence of nitrogen vacancies reduced the conduction band energy of g-C3 N4 from -0.75 to -0.5 eV and introduced plenty of defect levels in the band gap (just below the conductive band with a width of 0.45 eV). The oxygenation of g-C3 N4 induced the formation of oxygen-containing functional groups, such as C=O and C-O, as well as effectively enhancing the separation efficiency of photogenerated carriers and reducing the valence band energy from 2.05 to 2.30 eV. Therefore, the photocatalytic activity and photocurrent responses of RCNO were about nine and eight times higher than that of g-C3 N4 , respectively.

A Rapid Microwave-Assisted Thermolysis Route to Highly Crystalline Carbon Nitrides for Efficient Hydrogen Generation.

Highly crystalline graphitic carbon nitride (g-C3 N4 ) with decreased structural imperfections benefits from the suppression of electron-hole recombination, which enhances its hydrogen generation activity. However, producing such g-C3 N4 materials by conventional heating in an electric furnace has proven challenging. Herein, we report on the synthesis of high-quality g-C3 N4 with reduced structural defects by judiciously combining the implementation of melamine-cyanuric acid (MCA) supramolecular aggregates and microwave-assisted thermolysis. The g-C3 N4 material produced after optimizing the microwave reaction time can effectively generate H2 under visible-light irradiation. The highest H2 evolution rate achieved was 40.5 μmol h-1 , which is two times higher than that of a g-C3 N4 sample prepared by thermal polycondensation of the same supramolecular aggregates in an electric furnace. The microwave-assisted thermolysis strategy is simple, rapid, and robust, thereby providing a promising route for the synthesis of high-efficiency g-C3 N4 photocatalysts.

In Situ Solid-State Synthesis of a AgNi/g-C3 N4 Nanocomposite for Enhanced Photoelectrochemical and Photocatalytic Activity.

A graphitic carbon nitride (g-C3 N4 ) polymer matrix was embedded with AgNi alloy nanoparticles using a simple and direct in situ solid-state heat treatment method to develop a novel AgNi/g-C3 N4 photocatalyst. The characterization confirms that the AgNi alloy particles are homogeneously distributed throughout the g-C3 N4 matrix. The catalyst shows excellent photoelectrochemical activity for water splitting with a maximum photocurrent density of 1.2 mA cm-2 , which is the highest reported for doped g-C3 N4 . Furthermore, a detailed experimental study of the photocatalytic degradation of Rhodamine B (RhB) dye using doped g-C3 N4 showed the highest reported degradation efficiency of approximately 95 % after 90 min. The electronic conductivity increased upon incorporation of AgNi alloy nanoparticles on g-C3 N4 and the material showed efficient charge carrier separation and transfer characteristics, which are responsible for the enhanced photoelectrochemical and photocatalytic performance under visible light.

Tubular g‐C3N4 Isotype Heterojunction: Enhanced Visible‐Light Photocatalytic Activity through Cooperative Manipulation of Oriented Electron and Hole Transfer

A tubular g-C3 N4 isotype heterojunction (TCNH) photocatalyst was designed for cooperative manipulation of the oriented transfer of photogenerated electrons and holes to pursue high catalytic performance. The adduct of cyanuric acid and melamine (CA·M) is first hydrothermally treated to assemble into hexagonal prism crystals; then the hybrid precursors of urea and CA·M crystals are calcined to form tubular g-C3 N4 isotype heterojunctions. Upon visible-light irradiation, the photogenerated electrons transfer from g-C3 N4 (CA·M) to g-C3 N4 (urea) driven by the conduction band offset of 0.05 eV, while the photogenerated holes transfer from g-C3 N4 (urea) to g-C3 N4 (CA·M) driven by the valence band offset of 0.18 eV, which renders oriented transfer of the charge carriers across the heterojunction interface. Meanwhile, the tubular structure of TCNH is favorable for oriented electron transfer along the longitudinal dimension, which greatly decreases the chance of charge carrier recombination. Consequently, TCNH exhibits a high hydrogen evolution rate of 63 μmol h(-1) (0.04 g, λ > 420 nm), which is nearly five times of the pristine g-C3 N4 and higher than most of the existing g-C3 N4 photocatalysts. This study demonstrates that isotype heterojunction structure and tubular structure can jointly manipulate the oriented transfer of electrons and holes, thus facilitating the visible-light photocatalysis.

ChemInform Abstract: Graphitic Carbon Nitride Polymers Toward Sustainable Photoredox Catalysis

AbstractReview: [91 refs.

Graphitic Carbon Nitride Polymers toward Sustainable Photoredox Catalysis.

As a promising two-dimensional conjugated polymer, graphitic carbon nitride (g-C3 N4 ) has been utilized as a low-cost, robust, metal-free, and visible-light-active photocatalyst in the field of solar energy conversion. This Review mainly describes the latest advances in g-C3 N4 photocatalysts for water splitting. Their application in CO2 conversion, organosynthesis, and environmental purification is also briefly discussed. The methods to modify the electronic structure, nanostructure, crystal structure, and heterostructure of g-C3 N4 , together with correlations between its structure and performance are illustrated. Perspectives on the challenges and opportunities for the future exploration of g-C3 N4 photocatalysts are provided. This Review will promote the utilization of g-C3 N4 materials in the fields of photocatalysis, energy conversion, environmental remediation, and sensors.