Search query: graphitic  carbon  nitride  for  heterogeneous photocatalysis

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abstract: Polymeric graphitic carbon nitride (for simplicity, g C3N4) is a layered material similar to graphene, being composed of only C, N, and some impurity H. Contrary to graphenes, g C3N4 is a medium band gap semiconductor and an effective photocatalyst for a broad variety of reactions, and it possesses a high thermal and chemical stability In this Perspective, we describe the polycondensation of this structure, how to modify band positions and band gap by doping and copolymerization, and how to texture the organic solid to make it an effective photocatalyst. We then describe the photochemical splitting of water and some mild and selective photooxidation reactions catalyzed by g C3N4.
author_names: Xinchen Wang

Siegfried Blechert

Markus Antonietti
title: Polymeric Graphitic Carbon Nitride for Heterogeneous Photocatalysis
year: 2012

abstract: Polymeric graphitic carbon nitride (g C3N4) 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 C3N4 and carbon materials on photocatalytic action is vital to further development of metal free semiconductors in future studies. Here, recent advances of carbon/g C3N4 hybrids on various photocatalytic applications are reviewed. The dominant governing factors by inducing carbon into g C3N4 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 C3N4 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 C3N4 photocatalysts are presented.
author_names: Lei Cheng

Huaiwu Zhang

Xiaoning Li

Jiajie Fan

Quanjun Xiang
title: Carbon Graphitic Carbon Nitride Hybrids for Heterogeneous Photocatalysis.
venue: Small
year: 2020

abstract: Abstract Water bodies throughout the world are severely affected by the discharge of industrial effluents contaminated with xenobiotic and recalcitrant substances. Due to the low biodegradability of these compounds, conventional treatments have proven to be insufficient for their removal. Although heterogeneous photocatalysis poses an alternative for the treatment of these substances, the overall solar activity of conventional photocatalysts (such as TiO2) is very limited because of their wide bandgap. Thus, new photocatalysts such as graphitic carbon nitride (g C3N4) which exhibits catalytic activity using longer wavelengths, are receiving increasing attention. In this work, g C3N4 irradiated with a high energy electron beam was investigated for the degradation of Direct Blue 1 azo dye. g C3N4 was synthesized by pyrolysis of urea and irradiated at doses between 2.2 and 25.0 kGy for different times. The irradiated material was characterized by X ray diffraction (XRD) electron spin resonance (ESR) Fourier transform infrared spectroscopy (FTIR) UV Vis spectroscopy and transmission electron microscopy (TEM) together with BET surface area measurements. The results showed that the irradiation of the catalyst improved its dye adsorption ability, and 5 kGy was found to be the optimum irradiation dose, increasing the maximum dye adsorption capacity of irradiated g C3N4 to 73.76 mg/g. No significant differences in the pseudo first order kinetic model constants of the photocatalytic degradation of the dye were observed as a result of the irradiation treatment, perhaps due to the blocking of the active sites of the catalyst after the adsorption step, but a 1.4 times higher activity was attained for the irradiated sample upon H2O2 addition. The presence of H2O2 promoted the photocatalytic degradation process, reaching 99% dye removal in 40 min, and improved the reusability of the catalyst. The proposed modification of g C3N4 holds promise to enhance its activity.
author_names: Grace Picho-Chillan

Roberto C Dante

Florinella Munoz-Bisesti

Pablo Martin-Ramos

Pedro Chamorro-Posada

Paul Vargas-Jentzsch

Francisco Manuel Sanchez-Arevalo

Christian Sandoval-Pauker

Dario Rutto
title: Photodegradation of Direct Blue 1 azo dye by polymeric carbon nitride irradiated with accelerated electrons
venue: Materials Chemistry and Physics
year: 2019

abstract: The creation and development of efficient solar energy conversion systems for artificial photosynthesis is one of the challenges of modern chemistry and materials. Currently, the search for sustainable and stable photocatalytic systems for CO2 reduction by visible light is being actively pursued. Many useful and energy rich chemicals (e.g. CH3OH and HCOOH) can be obtained by photocatalytic CO2 reduction, which can reduce the emissions of greenhouse gases. Recently, significant improvements have been achieved in the area of CO2 reduction by using a heterogeneous photocatalyst under visible light irradiation. However, most of the catalysts screened did not exceed the state of the art system with turnover numbers (TONs) of approximately 200 and apparent quantum yields (AQYs) of approximately 2 The introduction of melon based graphitic carbon nitride (gC3N4) polymers as solar energy transducers has significantly extended the scope of conventional inorganic photocatalysts to polymeric photocatalysts. The latter is even more promising than the conventional photocatalysts because it is metal free, sustainable, and has demonstrated the ability to induce water splitting, CO2 reduction, and selective organic synthesis by means of visible light. The use of g C3N4 for CO2 reduction is an emerging research topic that couples organic basic functionality to photocatalytic functionality and allows for activation/adsorption and reduction of CO2. In the previous system for CO2 to CO photocatalytic conversion the quantum yield is less than 1. Recently, Maeda and co workers have developed a promising heterogeneous system for the reduction of CO2 into formic acid under visible light irradiation by merging organometallic chemistry with polymer photocatalysis by using g C3N4 and a ruthenium complex as light harvesting units and catalytic active sites, respectively. By carefully optimizing the heterogeneous catalyst and the reaction conditions the AQY was remarkably enhanced to 5.7 with a high TON of >1000, which are the highest values for g C3N4 and are better than other heterogeneous photocatalysts working with visible light. The authors promote surface kinetics for both the reduction reaction and charge transfer by chemically modifying g C3N4 with a Ru complex by means of a surface chemistry strategy. The surface Ru complex catalysis is demonstrated to change reaction pathway to produce the more valuable product, formic acid, rather than carbon monoxide. Four different Ru based complexes (Scheme 1) trans (Cl)[Ru(bpyX2)(CO)2Cl2] (bpyX2 2,2' bipyridine with substituent X in the 4 position, X H, CH3, PO3H2, or CH2PO3H2) were used as kinetic promoters for CO2 reduction, along with a suitable reaction environment to increase the efficiency of the overall process. Mesoporous graphitic carbon nitride (mpg C3N4) with a specific surface area of 180 m gC/1 and pore volume of 0.7 cm gC/1 was selected as a light harvesting semiconductor. The surface of the porous organic photocatalyst is covered with amino groups, which can be easily functionalized by surface organic chemistry. This feature is unique and is not available for traditional inorganic photocatalysts. Results indicated that RuP and RuCP could adsorb on the surface of mpg C3N4 owing to the intense interaction between acid and base functional groups on the two units. However, no adsorption was found to occur for RuH and RuMe, which do not have an anchoring group. The rich amino groups on the surface of the gScheme 1. Photocatalytic CO2 reduction by Ru complex anchored g C3N4 photocatalysts. C.B. Conduction band, V.B. Valance band, D electron donor. Reprinted with permission from Ref. [1]
author_names: Guigang Zhang

Zhi-An Lan

Xinchen Wang
title: Merging Surface Organometallic Chemistry with Graphitic Carbon Nitride Photocatalysis for CO2 Photofixation
year: 2015

abstract: Photoredox catalysis comprising homogeneous transition metal based systems, organic dyes, and semiconductors, has become a universal tool to catalyze a wide variety of chemical reactions with high selectivity and under mild conditions using visible light irradiation. This Minireview summarizes recent progress in photoredox catalysis mediated by heterogeneous carbon nitride materials such as mesoporous graphitic carbon nitride (mpg CN) polymeric carbon nitride, and potassium poly(heptazine imides) (K PHI) Because of the high thermal, chemical, and photostability of these materials, as well as favorable conduction and valence band positions, carbon nitrides expand the reaction range of photocatalysis to many novel reactions, such as photocatalytic activation of elemental sulfur to furnish a convenient chemical route to organosulfur compounds.
author_names: Aleksandr Savateev

Indrajit Ghosh

Burkhard Konig

Markus Antonietti
title: Photoredox Catalytic Organic Transformations using Heterogeneous Carbon Nitrides.
venue: Angewandte Chemie
year: 2018

abstract: The future development of chemistry entails environmentally friendly and energy sustainable alternatives for organic transformations. Visible light photocatalysis can address these challenges, as reflected by recent intensive scientific endeavours to this end. This review covers state of the art accomplishments in visible light induced selective organic transformations by heterogeneous photocatalysis. The discussion comprises three sections based on the photocatalyst type: metal oxides such as TiO2, Nb2O5 and ZnO; plasmonic photocatalysts like nanostructured Au, Ag or Cu supported on metal oxides; and polymeric graphitic carbon nitride. Finally, recent strides in bridging the gap between photocatalysis and other areas of catalysis will be highlighted with the aim of overcoming the existing limitations of photocatalysis by developing more creative synthetic methodologies.
author_names: Xianjun Lang

Xiaodong Chen

Jincai Zhao
title: Heterogeneous visible light photocatalysis for selective organic transformations.
venue: Chemical Society reviews
year: 2014

abstract: Abstract Developing bioinspired artificial Z scheme heterojunction photocatalysts with exceedingly well performance of visible light harnessing along with optimum band edge potentials is a robustly prominent avenue to combat the environmental and energy crisis. The current scenario in fixation of water shortages all over the world is utilisation of green and economical processes to maintain sustainability. In this regard, hybridizing fascinating metal free polymeric conjugated graphitic carbon nitride (g C3N4) with other components to tailor an effectual visibly driven photocatalyst has triggered a superfluity in the field of photocatalysis. Considering the great adherence and eloquent progress in exploitation of g C3N4 goaded Z scheme nanohybrids, we herein present an all inclusive and updated study about photocatalytic wastewater treatment including pollutant degradation and bacterial inactivation. An in depth overview comprising traditional photocatalysis along with Z scheme photocatalytic systems have been exploited and discussed with respect to their facile synthesis techniques and application in environmental restoration. With revamp strategies, g C3N4 based Z scheme photocatalytic systems provide broad range visible light absorption and efficient space separation of photo generated charge carriers, resulting in efficacious photoactivity. The mechanistic insights inferring photocarriers migration and separation along with the generation of reactive radical species involved in the photodegradation process has also been highlighted and discussed. Finally, an all embracing conclusive remark is presented regarding present studies and future perspectives for the development of g C3N4 goaded Z scheme photocatalysis.
author_names: Abhinandan Kumar

Pankaj Raizada

Pardeep Singh

Reena V Saini

Adesh K Saini

Ahmad Hosseini-Bandegharaei
title: Perspective and status of polymeric graphitic carbon nitride based Z scheme photocatalytic systems for sustainable photocatalytic water purification
year: 2020

abstract: Advanced oxidation processes (AOPs) have attracted much interest in the field of water treatment owing to their high removal efficiency for refractory organic contaminants. Graphitic carbon nitride (g C3N4) based catalysts with high performance and cost effectiveness are promising heterogeneous catalysts for AOPs. Most research on g C3N4 based catalysts focuses on photocatalytic oxidation, but increasingly researchers are paying attention to the application of g C3N4 based catalysts in other AOPs beyond photocatalysis. This review aims to concisely highlight recent state of the art progress of g C3N4 based catalysts in AOPs beyond photocatalysis. Emphasis is made on the application of g C3N4 based catalysts in three classical AOPs including Fenton based processes, catalytic ozonation and persulfates activation. The catalytic performance and involved mechanism of g C3N4 based catalysts in these AOPs are discussed in detail. Meanwhile, the effect of water chemistry including pH, water temperature, natural organic matter, inorganic anions and dissolved oxygen on the catalytic performance of g C3N4 based catalysts are summarized. Moreover, the reusability, stability and toxicity of g C3N4 based catalysts in water treatment are also mentioned. Lastly, perspectives on the major challenges and opportunities of g C3N4 based catalysts in these AOPs are proposed for better developments in the future research.
author_names: Chengyun Zhou

Guangming Zeng

Xiaopei Li
title: Recent advances in application of graphitic carbon nitride based catalysts for degrading organic contaminants in water through advanced oxidation processes beyond photocatalysis: A critical review.
venue: Water research
year: 2020

abstract: Abstract Characteristics of polymeric and electronic structure of graphitic carbon nitride (g C3N4) responsible for the photocatalytic activity were analyzed with oxidation reaction of nitrogen monoxide (NO) and various kinds of spectroscopies. The photocatalytic activity per surface area was increased with increasing the preparation temperature up to 520 degC, and was decreased above 520 degC while the visible light absorbance and the relative surface area was increased with the preparation temperature up to 650 degC. Laser desorption/ionization mass spectrometry (LDI MS) showed that the content of cyano group connected with tri s triazine unit in g C3N4 increases with increasing the preparation temperature and that g C3N4 with higher activity per surface area contained smaller amount of cyano group. Additionally, the degree of polymerization and the planarity of carbon nitride layer possibly contributed for formation of mid gap levels that increases the number of unpaired electron. The formation of the mid gap level was not effective for the photocatalytic activity, but rather deactivated g C3N4.
author_names: Taizo Sano

Hiroaki Sato

Tomoko Hori

Tsutomu Hirakawa

Yoshiyuki Teramoto

Kazuhide Koike
title: Effects of polymeric and electronic structure of graphitic carbon nitride (g C3N4) on oxidative photocatalysis
venue: Molecular Catalysis
year: 2019

abstract: In recent years, various facile and low cost methods have been developed for the synthesis of advanced nanostructured photocatalytic materials. These catalysts are required to mitigate the energy crisis, environmental deterioration, including water and air pollution. Among the various semiconductors explored, recently novel classes of polymeric graphitic carbon nitride (g C3N4) based heterogeneous photocatalysts have established much greater importance because of their unique physiochemical properties, large surface area, low price, and long service life, ease of synthesis, product scalability, controllable band gap properties, low toxicity, and high photocatalytic activity. The present comprehensive review focuses on recent achievements in a number of facile chemical synthesis methods for semiconducting polymeric carbon nitrides and their heterogeneous nanohybrids with various dopants, nanostructured metals, metal oxides, and nanocarbons, as well as the parameters influencing their physiochemical properties and photocatalytic efficiency, which are discussed with reference to various catalytic applications such as air (NOx) purification, wastewater treatment, hydrogen generation, CO2 reduction, and chemical transformation. The mechanisms for the superior photocatalytic activity of polymeric g C3N4 based heterogeneous photocatalysts are also discussed. Finally, the challenges, prospects, and future directions for photocatalytic polymeric g C3N4 based semiconducting materials are described.
author_names: Kakarla Raghava Reddy

Ch Venkata Reddy

Mallikarjuna N Nadagouda

Nagaraj P Shetti

Shim Jaesool

Tejraj M Aminabhavi
title: Polymeric graphitic carbon nitride (g C3N4) based semiconducting nanostructured materials: Synthesis methods, properties and photocatalytic applications.
venue: Journal of environmental management
year: 2019