scholarly journals Unraveling fundamental active units in carbon nitride for photocatalytic oxidation reactions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chaofeng Huang ◽  
Yaping Wen ◽  
Jin Ma ◽  
Dandan Dong ◽  
Yanfei Shen ◽  
...  
Keyword(s):  
Charge Separation ◽  
Photocatalytic Oxidation ◽  
Carbon Nitride ◽  
Molecular Structures ◽  
Electronic Coupling ◽  
Oxidation Reactions ◽  
Condensed Form ◽  
Covalently Bonded ◽  
Polymeric Structures ◽  
Photocatalytic Processes

AbstractCovalently bonded carbon nitride (CN) has stimulated extensive attention as a metal-free semiconductor. However, because of the complexity of polymeric structures, the acquisition of critical roles of each molecular constituent in CN for photocatalysis remains elusive. Herein, we clarify the fundamental active units of CN in photocatalysis by synthesizing CN with more detailed molecular structures. Enabled by microwave synthesis, the as-prepared CN consists of distinguishable melem (M1) and its incomplete condensed form (M2). We disclose rather than the traditional opinion of being involved in the whole photocatalytic processes, M1 and M2 make primary contributions in light absorption and charge separation, respectively. Meanwhile, oxygen molecules are unusually observed to be activated by participating in the photoexcited processes via electronic coupling mainly to M2. As a result, such CN has a higher activity, which was up to 8 times that of traditional bulk CN for photocatalytic oxidation of tetracycline in water.

Unraveling Minimum Active Units and Substrate Activation for Carbon Nitride in Photocatalytic Oxidation Reactions

2020 ◽  
Author(s):  
Chaofeng Huang ◽  
Yaping Wen ◽  
Dandan Dong ◽  
Yanfei Shen ◽  
Songqin Liu ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Carbon Nitride ◽  
Value Added ◽  
Electronic Coupling ◽  
Oxidation Reactions ◽  
Active Structure ◽  
Substrate Activation ◽  
Condensed Form ◽  
Water Cleaning ◽  
Photocatalytic Reactions

<p>Covalent bonded carbon nitride (CN) has stimulated extensive attentions from photosynthesis to optoelectronics. However, the acquisition of correct numbers beyond stoichiometry and composition remains indefinable. Moreover, the electronic coupling by the substrates to the photoexcitation processes in value-added oxidation reactions is essential, but still poorly understood. Herein, we report by far the minimum active structure of CN by constructing fragments consisting of melem (M1) and its incomplete condensed form with cyanide termination (M2). Surprisingly, such configuration endowed a boosted activity of 11 times of traditional bulk CN in photocatalytic oxidation of tetracycline as a showcase application of water cleaning and sanitation. The mechanism studies disclosed that M1 and M2 were primarily responsible for light absorption and charge separation, respectively;<a></a><a> meanwhile the electronic coupling by the O<sub>2</sub> substrate participated the photoexcited processes thus synergistically enhanced the photocatalytic reactions.</a></p>

Unraveling Minimum Active Units and Substrate Activation for Carbon Nitride in Photocatalytic Oxidation Reactions

2020 ◽  
Author(s):  
Chaofeng Huang ◽  
Yaping Wen ◽  
Dandan Dong ◽  
Yanfei Shen ◽  
Songqin Liu ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Carbon Nitride ◽  
Value Added ◽  
Electronic Coupling ◽  
Oxidation Reactions ◽  
Active Structure ◽  
Substrate Activation ◽  
Condensed Form ◽  
Water Cleaning ◽  
Photocatalytic Reactions

<p>Covalent bonded carbon nitride (CN) has stimulated extensive attentions from photosynthesis to optoelectronics. However, the acquisition of correct numbers beyond stoichiometry and composition remains indefinable. Moreover, the electronic coupling by the substrates to the photoexcitation processes in value-added oxidation reactions is essential, but still poorly understood. Herein, we report by far the minimum active structure of CN by constructing fragments consisting of melem (M1) and its incomplete condensed form with cyanide termination (M2). Surprisingly, such configuration endowed a boosted activity of 11 times of traditional bulk CN in photocatalytic oxidation of tetracycline as a showcase application of water cleaning and sanitation. The mechanism studies disclosed that M1 and M2 were primarily responsible for light absorption and charge separation, respectively;<a></a><a> meanwhile the electronic coupling by the O<sub>2</sub> substrate participated the photoexcited processes thus synergistically enhanced the photocatalytic reactions.</a></p>

Structure-Mediated Charge Separation in Boron Carbon Nitride for Enhanced Photocatalytic Oxidation of Alcohol

ChemSusChem ◽  
2018 ◽  
Vol 11 (22) ◽  
pp. 3949-3955 ◽  
Author(s):  
Min Zhou ◽  
Pengju Yang ◽  
Sibo Wang ◽  
Zhishan Luo ◽  
Caijin Huang ◽  
...  
Keyword(s):  
Charge Separation ◽  
Photocatalytic Oxidation ◽  
Carbon Nitride ◽  
Boron Carbon Nitride ◽  
Boron Carbon

scholarly journals β-Ketophosphonates with Pentalenofuran Scaffolds Linked to the Ketone Group for the Synthesis of Prostaglandin Analogs

2021 ◽  
Vol 22 (13) ◽  
pp. 6787
Author(s):  
Constantin I. Tănase ◽  
Constantin Drăghici ◽  
Miron Teodor Căproiu ◽  
Anamaria Hanganu ◽  
Gheorghe Borodi ◽  
...  
Keyword(s):  
Lithium Salt ◽  
Methyl Esters ◽  
Secondary Compounds ◽  
Molecular Structures ◽  
Keto Group ◽  
High Yield ◽  
Oxidation Reactions ◽  
Prostaglandin Analogues ◽  
X Ray ◽  
Oxidation Of Alcohols

β-Ketophosphonates with pentalenofurane fragments linked to the keto group were synthesized. The bulky pentalenofurane skeleton is expected to introduce more hindrance in the prostaglandin analogues of type III, greater than that obtained with the bicyclo[3.3.0]oct(a)ene fragments of prostaglandin analogues I and II, to slow down (retard) the inactivation of the prostaglandin analogues by oxidation of 15α-OH to the 15-keto group via the 15-PGDH pathway. Their synthesis was performed by a sequence of three high yield reactions, starting from the pentalenofurane alcohols 2, oxidation of alcohols to acids 3, esterification of acids 3 to methyl esters 4 and reaction of the esters 4 with lithium salt of dimethyl methanephosphonate at low temperature. The secondary compounds 6b and 6c were formed in small amounts in the oxidation reactions of 2b and 2c, and the NMR spectroscopy showed that their structure is that of an ester of the acid with the starting alcohol. Their molecular structures were confirmed by single crystal X-ray determination method for 6c and XRPD powder method for 6b.

scholarly journals Carbon Nitride Quantum Dots Modified TiO2 Inverse Opal Photonic Crystal for Solving Indoor VOCs Pollution

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 464
Author(s):  
Jie Yu ◽  
Angel Caravaca ◽  
Chantal Guillard ◽  
Philippe Vernoux ◽  
Liang Zhou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Nitride ◽  
Sol Gel ◽  
Green Energy ◽  
Inverse Opal ◽  
Oxidation Reactions ◽  
Composite Photocatalyst ◽  
Colloidal Photonic Crystals ◽  
Inverse Opal Structure

Indoor toxic volatile organic compounds (VOCs) pollution is a serious threat to people’s health and toluene is a typical representative. In this study, we developed a composite photocatalyst of carbon nitride quantum dots (CNQDs) in situ-doped TiO2 inverse opal TiO2 IO for efficient degradation of toluene. The catalyst was fabricated using a sol-gel method with colloidal photonic crystals as the template. The as-prepared catalyst exhibited excellent photocatalytic performance for degradation of toluene. After 6 h of simulated sunlight irradiation, 93% of toluene can be converted into non-toxic products CO2 and H2O, while only 37% of toluene is degraded over commercial P25 in the same condition. This greatly enhanced photocatalytic activity results from two aspects: (i) the inverse opal structure enhances the light harvesting while providing adequate surface area for effective oxidation reactions; (ii) the incorporation of CNQDs in the framework of TiO2 increases visible light absorption and promotes the separation of photo-generated charges. Collectively, highly efficient photocatalytic degradation of toluene has been achieved. In addition, it can be expanded to efficient degradation of organic pollutants in liquid phase such as phenol and Rhodamine B. This study provides a green, energy saving solution for indoor toxic VOCs removal as well as for the treatment of organic wastewater.

Covalent decoration onto the outer walls of double walled carbon nanotubes with perylenediimides

2015 ◽  
Vol 3 (19) ◽  
pp. 4960-4969 ◽  
Author(s):  
Myriam Barrejón ◽  
Sara Pla ◽  
Isadora Berlanga ◽  
María J. Gómez-Escalonilla ◽  
Luis Martín-Gomis ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Separation ◽  
Transient Absorption ◽  
Femtosecond Transient Absorption ◽  
Covalently Bonded ◽  
Absorption Studies ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Three new covalently bonded DWCNT–PDIs have been synthesized and characterized, showing exclusively functionalization of the outer walls leaving the inner walls intact. Femtosecond transient absorption studies were performed to seek evidence of charge separation in these hybrids.

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