Emerging trends in sensors based on carbon nitride materials

The Analyst ◽  
2019 ◽  
Vol 144 (5) ◽  
pp. 1475-1491 ◽  
Author(s):  
Marilyn Mary Xavier ◽  
P. Radhakrishnan Nair ◽  
Suresh Mathew
Keyword(s):  
Carbon Nitride ◽  
Functional Materials ◽  
New Class ◽  
Emerging Trends ◽  
Carbon Nitrides ◽  
Carbon Nitride Materials

A new class of functional materials, carbon nitrides, has recently attracted the attention of researchers.

scholarly journals Solar Energy Harvesting with Carbon Nitrides: Do We Understand the Mechanism?

2018 ◽  
Author(s):  
Wolfgang Domcke ◽  
Johannes Ehrmaier ◽  
Andrzej L. Sobolewski
Keyword(s):  
Excited State ◽  
Solar Energy ◽  
Water Molecule ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydroxyl Radicals ◽  
Carbon Nitride ◽  
Carbon Nitrides ◽  
Polymeric Carbon ◽  
Carbon Nitride Materials

The photocatalytic splitting of water into molecular hydrogen and molecular oxygen with sunlight is the dream reaction for solar energy conversion. Since decades, transition-metal-oxide semiconductors and supramolecular organometallic structures have been extensively explored as photocatalysts for solar water splitting. More recently, polymeric carbon nitride materials consisting of triazine or heptazine building blocks have attracted considerable attention as hydrogen-evolution photocatalysts. The mechanism of hydrogen evolution with polymeric carbon nitrides is discussed throughout the current literature in terms of the familiar concepts developed for photoelectrochemical water splitting with semiconductors since the 1970s. We discuss in this perspective an alternative mechanistic paradigm for photoinduced water splitting with carbon nitrides, which focusses on the specific features of the photochemistry of aromatic N-heterocycles in aqueous environments. It is shown that a water molecule which is hydrogen-bonded to an N-heterocycle can be decomposed into hydrogen and hydroxyl radicals by two simple sequential photochemical reactions. This concept is illustrated by first-principles calculations of excited-state reaction paths and their energy profiles for hydrogen-bonded complexes of pyridine, triazine and heptazine with a water molecule. It is shown that the excited-state hydrogen-transfer and hydrogen-detachment reactions are essentially barrierless, in sharp contrast to water oxidation in the electronic ground state, where high barriers prevail. We also discuss in some detail the products of possible reactions of the highly reactive hydroxyl radicals with the chromophores. We hypothesize that the challenge of efficient solar hydrogen generation with carbon-nitride materials is less the decomposition of water as such, but rather the controlled recombination of the photogenerated radicals to the closed-shell products H2 and H2O2.

Metal-Doped Carbon Nitrides: Synthesis, Structure and Applications

2021 ◽  
Author(s):  
Yuhan Bai ◽  
Yongjun Zheng ◽  
Zhuang Wang ◽  
Qing Hong ◽  
Songqin Liu ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Molecular Level ◽  
Wide Range ◽  
Carbon Nitrides ◽  
Common Strategy ◽  
Metal Doped ◽  
Carbon Nitride Materials

Doping of metal is a common strategy to regulate the structure of carbon nitride materials at the molecular level. A wide range of intriguing applications of metal-doped carbon nitride (M-CN)...

Accessing the rich carbon nitride materials chemistry by heat treatments of ammonium thiocyanate, NH4SCN

2019 ◽  
Vol 75 (4) ◽  
pp. 621-633
Author(s):  
Finn Krebs Larsen ◽  
Aref Hasen Mamakhel ◽  
Jacob Overgaard ◽  
Jens-Erik Jørgensen ◽  
Kenichi Kato ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Ambient Pressure ◽  
Ammonium Thiocyanate ◽  
Functional Materials ◽  
Chemical Diversity ◽  
Materials Chemistry ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Rich ◽  
Carbon Nitride Materials

Carbon nitride materials include functional materials, and their chemical diversity and complexity are becoming increasingly appreciated. Heating of NH4SCN leads to a range of new carbon nitride compounds, which have been structurally characterized by single-crystal X-ray diffraction. Heating at ambient pressure to 175°C leads to guanidinium thiocyanate, H6CN3SCN (1), and when maintaining that temperature for about 12 h a water-insoluble carbon nitride product is formed, which is a co-crystal between melamine and melamium thiocyanate, [H6C3N6]·[H10C6N11]+·[SCN]− (2). In situ powder X-ray diffraction measurements of this material reveal a gradual transformation from (2), via two intermediate products, to a final melon-like end product. The first of these forms between 350 and 400°C, and is an adduct of melam and melamium thiocyanate, [H9C6N11]·2[H10C6N11]+·2[SCN]− (3). The second forms between 400 and 480°C, and is identified as melem, 2,5,8-triamino-tri-s-triazine, H6C6N10 (4). On heating of (2) in a sealed ampoule to 600°C, various crystals were obtained and six crystal structures were determined from the batch: 1,3,5-triazine-2,4,6-triamino, H6C3N6 (5), 1,3,5-triazine-2,4-diamino, H5C3N5 (6), 1,1′,3,3′,5,5′-triazine-2,2′,4,4′-tetraamino, H8C6N10 (7), 2[H6C3N6]·[H10C6N11]+·[SCN]− (8) and 2[H6C3N6]·[H7C3N6]+·[SCN]− (9). Finally, a recrystallized decomposition product was found to be [H6C3N6]·[H7C3N6]+·[SCN]−·[H2O] (10).

scholarly journals Polymeric carbon nitrides and related metal-free materials for energy and environmental applications

2020 ◽  
Vol 8 (22) ◽  
pp. 11075-11116 ◽  
Author(s):  
Jesús Barrio ◽  
Michael Volokh ◽  
Menny Shalom
Keyword(s):  
Catalytic Properties ◽  
Functional Materials ◽  
Environmental Applications ◽  
Facile Synthesis ◽  
Metal Free ◽  
New Class ◽  
Wide Range ◽  
Carbon Nitrides ◽  
Polymeric Carbon

Carbon nitrides have emerged as a new class of functional materials for a wide range of energy and environmental applications due to their chemical, photophysical and catalytic properties as well as their low-price, facile synthesis and stability.

scholarly journals Carbon nitrides: synthesis and characterization of a new class of functional materials

2017 ◽  
Vol 19 (24) ◽  
pp. 15613-15638 ◽  
Author(s):  
T. S. Miller ◽  
A. Belen Jorge ◽  
T. M. Suter ◽  
A. Sella ◽  
F. Corà ◽  
...  
Keyword(s):  
Functional Properties ◽  
Functional Materials ◽  
Synthesis And Characterization ◽  
Next Generation ◽  
New Class ◽  
Carbon Nitrides

We examine the characterization of carbon nitrides and provide a perspective on their functional properties as next-generation materials.

scholarly journals Solar Energy Harvesting with Carbon Nitrides: Do We Understand the Mechanism?

2018 ◽  
Author(s):  
Wolfgang Domcke ◽  
Johannes Ehrmaier ◽  
Andrzej L. Sobolewski
Keyword(s):  
Excited State ◽  
Solar Energy ◽  
Water Molecule ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydroxyl Radicals ◽  
Carbon Nitride ◽  
Carbon Nitrides ◽  
Polymeric Carbon ◽  
Carbon Nitride Materials

The photocatalytic splitting of water into molecular hydrogen and molecular oxygen with sunlight is the dream reaction for solar energy conversion. Since decades, transition-metal-oxide semiconductors and supramolecular organometallic structures have been extensively explored as photocatalysts for solar water splitting. More recently, polymeric carbon nitride materials consisting of triazine or heptazine building blocks have attracted considerable attention as hydrogen-evolution photocatalysts. The mechanism of hydrogen evolution with polymeric carbon nitrides is discussed throughout the current literature in terms of the familiar concepts developed for photoelectrochemical water splitting with semiconductors since the 1970s. We discuss in this perspective an alternative mechanistic paradigm for photoinduced water splitting with carbon nitrides, which focusses on the specific features of the photochemistry of aromatic N-heterocycles in aqueous environments. It is shown that a water molecule which is hydrogen-bonded to an N-heterocycle can be decomposed into hydrogen and hydroxyl radicals by two simple sequential photochemical reactions. This concept is illustrated by first-principles calculations of excited-state reaction paths and their energy profiles for hydrogen-bonded complexes of pyridine, triazine and heptazine with a water molecule. It is shown that the excited-state hydrogen-transfer and hydrogen-detachment reactions are essentially barrierless, in sharp contrast to water oxidation in the electronic ground state, where high barriers prevail. We also discuss in some detail the products of possible reactions of the highly reactive hydroxyl radicals with the chromophores. We hypothesize that the challenge of efficient solar hydrogen generation with carbon-nitride materials is less the decomposition of water as such, but rather the controlled recombination of the photogenerated radicals to the closed-shell products H2 and H2O2.

Mechanism of photocatalytic water splitting with triazine-based carbon nitrides: insights from ab initio calculations for the triazine–water complex

2018 ◽  
Vol 20 (21) ◽  
pp. 14420-14430 ◽  
Author(s):  
Johannes Ehrmaier ◽  
Mikołaj J. Janicki ◽  
Andrzej L. Sobolewski ◽  
Wolfgang Domcke
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Water Splitting ◽  
Carbon Nitride ◽  
Model System ◽  
Photocatalytic Water Splitting ◽  
Water Complex ◽  
Carbon Nitrides ◽  
Carbon Nitride Materials

Valuable theoretical insights into the mechanism of photocatalytic water-splitting using triazine as a model system for carbon-nitride materials.

Photochemistry of carbon nitrides and heptazine derivatives

2021 ◽  
Author(s):  
Doyk Hwang ◽  
Cody W. Schlenker
Keyword(s):  
Carbon Nitride ◽  
Monomer Unit ◽  
Carbon Nitrides

This article highlights the photochemistry of heptazine derivatives, a structural monomer unit of carbon nitride photocatalysts.

scholarly journals Understanding spontaneous dissolution of crystalline layered carbon nitride for tuneable photoluminescent solutions and glasses

2021 ◽  
Author(s):  
Adam J. Clancy ◽  
Theo M. Suter ◽  
Alaric Taylor ◽  
Sayantan Bhattacharya ◽  
Thomas S. Miller ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
2D Materials ◽  
Carbon Nitrides

The spontaneous dissolution of 2D carbon nitrides with polytriazine imide (PTI) diverges dramatically from the inherent insolubility of other 2D materials such as graphene. The dissolution may be controlled to give tuneable photoluminescence.

scholarly journals Low-Temperature Synthesis of Solution Processable Carbon Nitride Polymers

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1646
Author(s):  
Junyi Li ◽  
Neeta Karjule ◽  
Jiani Qin ◽  
Ying Wang ◽  
Jesús Barrio ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Spatial Organization ◽  
Surface Display ◽  
Liquid Media ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
X Ray ◽  
N2 Atmosphere ◽  
Carbon Nitride Materials

Carbon nitride materials require high temperatures (>500 °C) for their preparation, which entails substantial energy consumption. Furthermore, the high reaction temperature limits the materials’ processability and the control over their elemental composition. Therefore, alternative synthetic pathways that operate under milder conditions are still very much sought after. In this work, we prepared semiconductive carbon nitride (CN) polymers at low temperatures (300 °C) by carrying out the thermal condensation of triaminopyrimidine and acetoguanamine under a N2 atmosphere. These molecules are isomers: they display the same chemical formula but a different spatial distribution of their elements. X-ray photoelectron spectroscopy (XPS) experiments and electrochemical and photophysical characterization confirm that the initial spatial organization strongly determines the chemical composition and electronic structure of the materials, which, thanks to the preservation of functional groups in their surface, display excellent processability in liquid media.

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