scholarly journals Direct Electrochemical Storage of Solar Energy in C‐Rich Polymeric Carbon Nitride Cell

2021 ◽  
pp. 2100111
Author(s):  
Lirong He ◽  
Xiao Tang ◽  
Yanhong Li ◽  
Ling Zhang ◽  
Guozhong Cao
Keyword(s):  
Solar Energy ◽  
Carbon Nitride ◽  
Electrochemical Storage ◽  
Polymeric Carbon

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.

scholarly journals Structure Tuning of Polymeric Carbon Nitride for Solar Energy Conversion: From Nano to Molecular Scale

Chem ◽  
2019 ◽  
Vol 5 (11) ◽  
pp. 2775-2813 ◽  
Author(s):  
Yang Wang ◽  
Soo Zeng Fiona Phua ◽  
Gang Dong ◽  
Xueqin Liu ◽  
Bing He ◽  
...  
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Carbon Nitride ◽  
Solar Energy Conversion ◽  
Molecular Scale ◽  
Polymeric Carbon

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.

Dissolution and Performing Homogeneous Photocatalysis of Polymeric Carbon Nitride

2018 ◽  
Author(s):  
Chaofeng Huang ◽  
Jing Wen ◽  
Yanfei Shen ◽  
Fei He ◽  
Li Mi ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Carbon Nitride ◽  
Heterogeneous Catalysts ◽  
Methane Sulfonic Acid ◽  
Environment Friendly ◽  
The Poor ◽  
Catalytic Sites ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon ◽  
First Time

<a></a><a>As a metal-free conjugated polymer, carbon nitride (CN) has attracted tremendous attention as heterogeneous (photo)catalysts. </a><a></a><a>By following prototype of enzymes, making all catalytic sites of accessible via homogeneous reactions is a promising approach toward maximizing CN activity, but hindered due to </a><a></a><a>the poor insolubility of CN</a>. Herein, we report the dissolution of CN in environment-friendly methane sulfonic acid and the homogeneous photocatalysis driven by CN for the first time with the activity boosted up to 10-times, comparing to the heterogeneous counterparts. Moreover, facile recycling and reusability, the <a>hallmark</a> of heterogeneous catalysts, were kept for the homogeneous CN photocatalyst via reversible precipitation using poor solvents. It opens new vista of CN in homogeneous catalysis and offers a successful example of polymeric catalysts in bridging gaps of homo/heterogeneous catalysis.

Infrared Response in a Polymeric Carbon Nitride Via an Upconversion Mechanism

2019 ◽  
Author(s):  
Zhengyuan Jin ◽  
Xiantao Jiang ◽  
Qitao Zhang ◽  
Shaolong Huang ◽  
Luhong Zhang ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Upconversion Mechanism ◽  
Polymeric Carbon

Tuning of the Oxygen Species Linker on the Surface of Polymeric Carbon Nitride to Promote the Photocatalytic Hydrogen Evolution Performance

ChemSusChem ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3605-3613 ◽  
Author(s):  
Qin Lei ◽  
Rongzhi Chen ◽  
Yurong Zhao ◽  
Huanyu Chen ◽  
Xinxin Long ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Carbon Nitride ◽  
Oxygen Species ◽  
Photocatalytic Hydrogen Evolution ◽  
Polymeric Carbon

Electrocatalytic Nitrogen Reduction by Transition Metal Single-Atom Catalysts on Polymeric Carbon Nitride

2021 ◽  
Author(s):  
Mei Zheng ◽  
Hongbin Xu ◽  
Yi Li ◽  
Kaining Ding ◽  
Yongfan Zhang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Carbon Nitride ◽  
Single Atom ◽  
Nitrogen Reduction ◽  
Polymeric Carbon

scholarly journals Emerging polymeric carbon nitride Z-scheme systems for photocatalysis

2021 ◽  
Vol 2 (3) ◽  
pp. 100355 ◽  
Author(s):  
Guangfu Liao ◽  
Chunxue Li ◽  
Xinzheng Li ◽  
Baizeng Fang
Keyword(s):  
Carbon Nitride ◽  
Polymeric Carbon

scholarly journals Water‐Soluble Polymeric Carbon Nitride Colloidal Nanoparticles for Highly Selective Quasi‐Homogeneous Photocatalysis

2019 ◽  
Vol 132 (1) ◽  
pp. 495-503 ◽  
Author(s):  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Christiane Adler ◽  
Marina Ilkaeva ◽  
Mariana Sardo ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Water Soluble ◽  
Colloidal Nanoparticles ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon
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