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.

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.

Photocatalytic splitting of water on s-triazine based graphitic carbon nitride: an ab initio investigation

2015 ◽  
Vol 3 (45) ◽  
pp. 23011-23016 ◽  
Author(s):  
K. Srinivasu ◽  
Swapan K. Ghosh
Keyword(s):  
Ab Initio ◽  
Water Splitting ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Photocatalytic Water Splitting ◽  
Semiconductor Photocatalyst

Ab initio investigations have been carried out to understand the mechanism of photocatalytic water splitting on a g-CN based semiconductor photocatalyst.

scholarly journals Challenges in calculating the bandgap of triazine-based carbon nitride structures

2017 ◽  
Vol 5 (10) ◽  
pp. 5115-5122 ◽  
Author(s):  
Stephan N. Steinmann ◽  
Sigismund T. A. G. Melissen ◽  
Tangui Le Bahers ◽  
Philippe Sautet
Keyword(s):  
Water Splitting ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Photocatalytic Water Splitting ◽  
Carbon Nitrides

Graphitic carbon nitrides form a popular family of materials, particularly as photoharvesters in photocatalytic water splitting cells.

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.

Conjugated polyene-functionalized graphitic carbon nitride with enhanced photocatalytic water-splitting efficiency

Carbon ◽  
2018 ◽  
Vol 129 ◽  
pp. 637-645 ◽  
Author(s):  
Haiping Li ◽  
Ha-Young Lee ◽  
Gi-Sang Park ◽  
Byong-June Lee ◽  
Jong-Deok Park ◽  
...  
Keyword(s):  
Water Splitting ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Photocatalytic Water Splitting

0D, 1D, 2D MOLYBDENUM DISULFIDE FUNCTIONALIZED BY 2D POLYMERIC CARBON NITRIDE FOR PHOTOCATALYTIC WATER SPLITTING

2021 ◽  
Author(s):  
Małgorzata Aleksandrzak ◽  
Martyna Baca ◽  
Michał Pacia ◽  
Karolina Anna Wenelska ◽  
Beata Zielinska ◽  
...  
Keyword(s):  
Molybdenum Disulfide ◽  
Water Splitting ◽  
Carbon Nitride ◽  
Photocatalytic Water Splitting ◽  
Polymeric Carbon

Ab-initio study on the two-dimensional anisotropic monolayers ScXY (X =S, Se; Y = Cl, Br) for the photocatalytic water splitting applications with high carrier mobilities

2022 ◽  
Author(s):  
Fei-Yang Xu ◽  
Yu Zhou ◽  
tian zhang ◽  
Zhao-Yi Zeng ◽  
Xiang-Rong Chen ◽  
...  
Keyword(s):  
Ab Initio ◽  
Water Splitting ◽  
Hierarchical Structures ◽  
Two Dimensional ◽  
Ab Initio Study ◽  
Photocatalytic Water Splitting ◽  
High Carrier

Metal oxyhalides have been broadly studied recently due to their hierarchical structures and promising functionalities. Herein, a thorough study of newly modeled monolayers ScXY (X = S, Se; Y =...

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.

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