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

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Unraveling fundamental active units in carbon nitride for photocatalytic oxidation reactions

Nature Communications ◽

10.1038/s41467-020-20521-5 ◽

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.

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Photocatalytic valorization of furfural to value-added chemicals via mesoporous carbon nitride: A possibility through metal-free pathway

Catalysis Science & Technology ◽

10.1039/d1cy01681d ◽

2021 ◽

Author(s):

Deepak Kumar Chauhan ◽

Venugopala Rao Battula ◽

Arkaprabha Giri ◽

Abhijit Patra ◽

Kamalakannan Kailasam

Keyword(s):

Mesoporous Carbon ◽

Photocatalytic Oxidation ◽

Carbon Nitride ◽

Value Added ◽

Solar Light ◽

Biomass Valorization ◽

Metal Free ◽

First Time ◽

Mesoporous Carbon Nitride ◽

Insight Into

Strategizing the exploitation of renewable solar light could undoubtedly provide new insight into the field of biomass valorization. Therefore, for the first time, we reported the heterogeneous photocatalytic oxidation route...

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

Catalysts ◽

10.3390/catal11040464 ◽

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.

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CePMo 12 O 40 / TiO 2 catalysts for photocatalytic oxidation of methane to value‐added organic oxygenates

International Journal of Energy Research ◽

10.1002/er.6629 ◽

2021 ◽

Author(s):

Liyan Ming ◽

Chunling Wang ◽

Yun Hang Hu

Keyword(s):

Photocatalytic Oxidation ◽

Value Added ◽

Oxidation Of Methane ◽

Organic Oxygenates

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In situ Solid-State NMR Studies of Photocatalytic Oxidation Reactions

ChemInform ◽

10.1002/chin.200626280 ◽

2006 ◽

Vol 37 (26) ◽

Author(s):

Sarah Pilkenton ◽

Daniel Raftery

Keyword(s):

Solid State ◽

Solid State Nmr ◽

Photocatalytic Oxidation ◽

Oxidation Reactions ◽

Nmr Studies

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Preparation of sodium and boron co-doped graphitic carbon nitride for the enhanced production of H2O2 via two-electron oxygen reduction and the degradation of 2,4-DCP via photocatalytic oxidation coupled with Fenton oxidation

Chemical Engineering Journal ◽

10.1016/j.cej.2021.134020 ◽

2022 ◽

Vol 431 ◽

pp. 134020

Author(s):

Yanyang Chu ◽

Xianglei Zheng ◽

Jinruo Fan

Keyword(s):

Oxygen Reduction ◽

Photocatalytic Oxidation ◽

Carbon Nitride ◽

Graphitic Carbon ◽

Fenton Oxidation ◽

Graphitic Carbon Nitride ◽

Enhanced Production ◽

Co Doped

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Selective photocatalytic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxaldehyde by polymeric carbon nitride-hydrogen peroxide adduct

Journal of Catalysis ◽

10.1016/j.jcat.2018.01.012 ◽

2018 ◽

Vol 359 ◽

pp. 212-222 ◽

Cited By ~ 26

Author(s):

M. Ilkaeva ◽

I. Krivtsov ◽

E.I. García-López ◽

G. Marcì ◽

O. Khainakova ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Photocatalytic Oxidation ◽

Carbon Nitride ◽

Polymeric Carbon

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Enhancement of Photocatalytic Oxidation of Glucose to Value-Added Chemicals on TiO2 Photocatalysts by A Zeolite (Type Y) Support and Metal Loading

Catalysts ◽

10.3390/catal10040423 ◽

2020 ◽

Vol 10 (4) ◽

pp. 423 ◽

Cited By ~ 2

Author(s):

Kamonchanok Roongraung ◽

Surawut Chuangchote ◽

Navadol Laosiripojana

Keyword(s):

Formic Acid ◽

Surface Area ◽

Gluconic Acid ◽

Photocatalytic Oxidation ◽

High Surface ◽

Sol Gel ◽

High Surface Area ◽

Value Added ◽

Incipient Wetness Impregnation ◽

Microwave Assisted

TiO2-based photocatalysts synthesized by the microwave-assisted sol-gel method was tested in the photocatalytic glucose conversion. Modifications of TiO2 with type-Y zeolite (ZeY) and metals (Ag, Cu, and Ag-Cu) were developed for increasing the dispersion of TiO2 nanoparticles and increasing the photocatalytic activity. Effects of the TiO2 dosage to zeolite ratio (i.e., TiO2/ZeY of 10, 20, 40, and 50 mol %) and the silica to alumina ratio in ZeY (i.e., SiO2:Al2O3 of 10, 100, and 500) were firstly studied. It was found that the specific surface area of TiO2/ZeY was 400–590 m2g−1, which was higher than that of pristine TiO2 (34.38 m2g−1). The good properties of 20%TiO2/ZeY photocatalyst, including smaller particles (13.27 nm) and high surface area, could achieve the highest photocatalytic glucose conversion (75%). Yields of gluconic acid, arabinose, xylitol, and formic acid obtained from 20%TiO2/ZeY were 9%, 26%, 4%, and 35%, respectively. For the effect of the silica to alumina ratio, the highest glucose conversion was obtained from SiO2:Al2O3 ratio of 100. Interestingly, it was found that the SiO2:Al2O3 ratio affected the selectivity of carboxylic products (gluconic acid and formic acid). At a low ratio of silica to alumina (SiO2:Al2O3 = 10), higher selectivity of the carboxylic products (gluconic acid = 29% and formic acid = 32%) was obtained (compared with other higher ratios). TiO2/ZeY was further loaded by metals using the microwave-assisted incipient wetness impregnation technique. The highest glucose conversion of 96.9 % was obtained from 1 wt. % Ag-TiO2 (40%)/ZeY. Furthermore, the bimetallic Ag-Cu-loaded TiO2/ZeY presented the highest xylitol yield of 12.93%.

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