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

2019 ◽  
Author(s):  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Marina Ilkaeva ◽  
Mariana Sardo ◽  
Luís Mafra ◽  
...  
Keyword(s):  
Active Sites ◽  
Carbon Nitride ◽  
Water Soluble ◽  
Colloidal Nanoparticles ◽  
Narrow Size Distribution ◽  
New Paradigm ◽  
Redox Transformations ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon ◽  
First Time

Heptazine-based polymeric carbon nitrides (PCN) are well established as promising photocatalysts for light-driven redox transformations. However, the activity of these materials is hampered by their low surface area translating into low concentration of active sites accessible for reactants. Herein, we report, for the first time, a bottom-up preparation of PCN nanoparticles with a narrow size distribution (~10±3 nm), which are fully soluble in water showing no gelation or precipitation over several months, and allow carrying out photocatalysis under <i>quasi</i>-homogeneous conditions. The rate of selective (up to 100%) photooxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde was enhanced by the factor of 6.5 as compared to conventional solid PCN and was accompanied by simultaneous H<sub>2</sub>O<sub>2</sub> production <i>via</i> reduction of oxygen. The dissolved photocatalyst can be easily recovered and re-dissolved by simple modulation of the ionic strength of the medium, without any loss of activity and selectivity. This work thus establishes a new paradigm of easily operable <i>quasi-</i>homogeneous photocatalysis with PCN, and opens up a route for other applications in which liquid aqueous operation or processing of PCN is required.

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

2019 ◽  
Author(s):  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Marina Ilkaeva ◽  
Mariana Sardo ◽  
Luís Mafra ◽  
...  
Keyword(s):  
Active Sites ◽  
Carbon Nitride ◽  
Water Soluble ◽  
Colloidal Nanoparticles ◽  
Narrow Size Distribution ◽  
New Paradigm ◽  
Redox Transformations ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon ◽  
First Time

Heptazine-based polymeric carbon nitrides (PCN) are well established as promising photocatalysts for light-driven redox transformations. However, the activity of these materials is hampered by their low surface area translating into low concentration of active sites accessible for reactants. Herein, we report, for the first time, a bottom-up preparation of PCN nanoparticles with a narrow size distribution (~10±3 nm), which are fully soluble in water showing no gelation or precipitation over several months, and allow carrying out photocatalysis under <i>quasi</i>-homogeneous conditions. The rate of selective (up to 100%) photooxidation of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde was enhanced by the factor of 6.5 as compared to conventional solid PCN and was accompanied by simultaneous H<sub>2</sub>O<sub>2</sub> production <i>via</i> reduction of oxygen. The dissolved photocatalyst can be easily recovered and re-dissolved by simple modulation of the ionic strength of the medium, without any loss of activity and selectivity. This work thus establishes a new paradigm of easily operable <i>quasi-</i>homogeneous photocatalysis with PCN, and opens up a route for other applications in which liquid aqueous operation or processing of PCN is required.

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

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

2019 ◽  
Vol 59 (1) ◽  
pp. 487-495 ◽  
Author(s):  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Christiane Adler ◽  
Marina Ilkaeva ◽  
Mariana Sardo ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Water Soluble ◽  
Colloidal Nanoparticles ◽  
Homogeneous Photocatalysis ◽  
Polymeric Carbon

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.

scholarly journals 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.

scholarly journals Sol–Gel Processing of Water-Soluble Carbon Nitride Enables High-Performance Photoanodes

2020 ◽  
Author(s):  
Christiane Adler ◽  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Lucía dos Santos-Gómez ◽  
Santiago García-Granda ◽  
...  
Keyword(s):  
Soft Matter ◽  
High Performance ◽  
Carbon Nitride ◽  
Sol Gel ◽  
Thin Layers ◽  
Water Soluble ◽  
New Paradigm ◽  
High Quality ◽  
Free Films ◽  
Gel Processing

In spite of the enormous promise that polymeric carbon nitride (PCN) materials hold for photoelectrochemical (PEC) applications, the fabrication of high-quality PCN photoelectrodes has been a largely elusive goal to date. Here we tackle this challenge by devising, for the first time, a sol–gel approach that enables facile preparation of photoanodes based on poly(heptazine imide) (PHI), a polymer belonging to the PCN family. The sol–gel process capitalizes on the use of a water-soluble PHI precursor composed of nanosized (~10 nm) particles that allows formation of a non-covalent hydrogel. The hydrogel can be deposited on a conductive substrate resulting in formation of mechanically stable porous polymeric thin layers (~400 nm), in contrast to the commonly obtained loosely attached thick particulate coatings. The resulting photoanodes exhibit unprecedented PEC performance in methanol reforming in neutral pH electrolytes with photocurrents of up to 177±27 mA cm<sup>-2</sup> (1 sun illumination) and 320±40 mA cm<sup>-2</sup> (2 sun illumination) at 1.23 V vs. RHE, maintaining such high photocurrents even down to ~0 V vs. RHE. These parameters permit effective operation even without any external electric bias, as demonstrated by bias-free photoreforming of methanol and glycerol, and highly selective (~100%) photooxidation of 4-methoxybenzyl alcohol (4-MBA). The robust binder-free films derived from sol–gel processing of water-soluble PCN thus represent a new paradigm for high-performance ‘soft-matter’ photoelectrocatalytic systems, and pave the way for further applications in which high-quality PCN films are required.

Enhanced photocatalytic hydrogen production from aqueous-phase methanol reforming over cyano-carboxylic bifunctionally-modified carbon nitride

2019 ◽  
Vol 55 (83) ◽  
pp. 12503-12506 ◽  
Author(s):  
Hao Tan ◽  
Peng Kong ◽  
Meixian Liu ◽  
Xianmo Gu ◽  
Zhanfeng Zheng
Keyword(s):  
Hydrogen Production ◽  
Active Sites ◽  
Carbon Nitride ◽  
Separation Efficiency ◽  
Promising Candidate ◽  
Methanol Reforming ◽  
Metal Free ◽  
Carrier Separation ◽  
Polymeric Carbon ◽  
Low Activity

Polymeric carbon nitride is a promising candidate for metal-free photocatalysis, but it is hampered by low activity due to poor carrier separation efficiency and lack of active sites.

scholarly journals Sol–Gel Processing of Water-Soluble Carbon Nitride Enables High-Performance Photoanodes

2020 ◽  
Author(s):  
Christiane Adler ◽  
Igor Krivtsov ◽  
Dariusz Mitoraj ◽  
Lucía dos Santos-Gómez ◽  
Santiago García-Granda ◽  
...  
Keyword(s):  
Soft Matter ◽  
High Performance ◽  
Carbon Nitride ◽  
Sol Gel ◽  
Thin Layers ◽  
Water Soluble ◽  
New Paradigm ◽  
High Quality ◽  
Binder Free ◽  
Gel Processing

In spite of the enormous promise that polymeric carbon nitride (PCN) materials hold for various applications, the fabrication of high-quality, binder-free PCN films and electrodes has been a largely elusive goal to date. Here we tackle this challenge by devising, for the first time, a sol–gel approach that enables facile preparation of thin films based on poly(heptazine imide) (PHI), a polymer belonging to the PCN family. The sol–gel process capitalizes on the use of a water-soluble PHI precursor that allows formation of a non-covalent hydrogel. The hydrogel can be deposited on conductive substrates resulting in formation of mechanically stable polymeric thin layers. The resulting photoanodes exhibit unprecedented PEC performance in alcohol reforming and selective (~100%) conversions with very high photocurrents down to ~0 V vs. RHE, which enables even effective operation under bias-free conditions. The robust binder-free films derived from sol–gel processing of water-soluble PCN thus represent a new paradigm for high-performance ‘soft-matter’ photoelectrocatalytic systems, and pave the way for further applications in which high-quality PCN films are required.

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