Photoluminescence and Raman Spectroscopy Studies of Carbon Nitride Films

Hernández-Torres, J.; Gutierrez-Franco, A.; González, P.; García-González, L.; Hernández-Quiroz, T.; Zamora‐Peredo, L.; Méndez-García, V.H.; Rosa, Agostinho C.

doi:10.1155/2016/5810592

Cited by 9 publications

(4 citation statements)

References 25 publications

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“…Raman spectroscopy of the catalysts displayed many bands in the spectral range from 400–1800 cm −1 (Figure 1l), characteristic of the skeletal vibrations of the carbon backbone and nitrogenated aromatic rings. [ 49,50 ] All samples presented E’ vibrations ascribed to C–N bonds at 543 cm −1 , C=N bonds at 1005 cm −1 , as well as the D and G bands associated with the sp 2 and sp 3 character and sp 2 bonded networks at 1434 and 1543 cm −1 , respectively. Interestingly, the D band increases significantly, while the C=N (E') and the G band nearly disappear when the urea ratio decreases.…”

Section: Resultsmentioning

confidence: 99%

Engineering the Surface Chemistry and Morphology of Polymeric Carbon Nitrides Towards Greener Heterogeneous Catalysts for Biodiesel Synthesis

Medeiros

Macina

Bicalho

et al. 2023

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Biodiesel remains one of the most promising alternatives to replace fossil fuel‐derived petrodiesel. Nonetheless, conventional biodiesel synthesis relies on homogeneous alkali‐based catalysts that involve long and tedious purification steps , increasing biodiesel production costs. Heterogeneous catalysts have emerged as promising alternatives to circumvent these drawbacks, as they can easily be recovered and reused. Herein, polymeric carbon nitride dots and nanosheets are synthesized through a solid‐phase reaction between urea and sodium citrate. Their morphology and surface chemistry are tuned by varying the precursor's ratio, and the materials are investigated as catalysts in the transesterification reaction of canola oil to biodiesel. A conversion of > 98% is achieved using a 5 wt% catalyst loading, oil to methanol ratio of 1:36 at 90 °C for 4 h, with the performance maintained over at least five reuse cycles. In addition, the effect of the transesterification reaction parameters on the reaction kinetics is evaluated, which follows a pseudo‐first‐order (PFO) regime. Combined with a deep understanding of the catalyst's surface, these results have allowed us to propose a reaction mechanism similar to the one observed for homogenous alkali catalysts. These carbon nitride‐based nanoparticles offer a metal‐free and cost‐effective alternative to conventional homogeneous and metal‐based heterogeneous catalysts.

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Section: Resultsmentioning

confidence: 99%

Engineering the Surface Chemistry and Morphology of Polymeric Carbon Nitrides Towards Greener Heterogeneous Catalysts for Biodiesel Synthesis

Medeiros

Macina

Bicalho

et al. 2023

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“…Recently, carbon nitride (CN) has become a current interest because of its unique properties such as non-toxicity, low cost, high photoluminescence intensity [11] and good photostability [12]. CN is a graphite like layered material where s-triazine (C 3 N 3 ) or tri-s-triazine (C 6 N 7 ) units connected with amino groups (-NH/NH 2 ) are held together through hydrogen bonds between the amino groups [13,14].…”

Section: Nitrate (Nomentioning

confidence: 99%

Copper Modified Carbon Nitride as Fluorescence Sensor for Nitrate Ions

Jasman¹,

Hendrik²,

Lee³

et al. 2017

MJAS

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In this study, newly developed copper modified CN composites were prepared and tested as a fluorescence sensor for detection of nitrate ions (NO 3-). The structure and chemical properties of CN and copper modified CN composites were investigated via Xray diffraction (XRD), Fourier transform infra-red (FTIR), diffuse reflectance ultraviolet-visible (DR UV-Vis) and fluorescence spectroscopies. Three emission sites represented as C=N, C=O and C-N moieties were suggested to contribute as sensing sites in CN and copper modified CN composites. The sensing capabilities of CN and copper modified CN composites toward NO 3 in the range of 300 to 1800 µM were determined via a quenching technique. The quenching efficiencies (K SV) of CN and copper modified CN composites were obtained from the Stern-Volmer plot. Among three emission peaks of CN, C=N sites were found to be the most sensitive site having the strongest interaction with NO 3-. By addition of Cu(0.5 mol%), the K SV of CN was improved from 2.11 x 10-4 to 5.27 x 10-4 µM-1. This study showed that with the addition of copper as modifier, the performance of CN can be improved and the composite can be used as potential fluorescence sensor for the detection of NO 3- .

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“…Compared to bulk CN, the well-separated D and G band in BCNFCo/CN composite can be explained as follows: the synthesis of BCNFCo/CN composite proceeds via exfoliation of bulk carbon nitride in glycerol/dichlorobenzene under continuous heat and stirring resulting in the formation of few-layered sheets. Due to the breaking of stacked structure and the formation of few-layered structures on the surface of BCNFCo, the restricted out-of-plane vibration becomes free to show well-separated D and G bands[111,112].The crystallinity of CN, BCNFCo and their composites was determined using x-ray diffraction (XRD) (figure4(c)). The crystal structure of the investigated phase Ba 2 Ca 0.67 Nb 0.67 Fe 0.33 Co 0.33 O 6−δ exhibited a 1:1 ordered cubic double perovskite structure (JCPDS# 49-0425).…”

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Water-splitting photoelectrodes consisting of heterojunctions of carbon nitride with a p-type low bandgap double perovskite oxide

Kumar¹,

Mulmi²,

Laishram³

et al. 2021

Nanotechnology

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Quinary and senary non-stoichiometric double perovskites such as Ba 2 Ca 0.66 Nb 1.34−x Fe x O 6−δ (BCNF) have been utilized for gas sensing, solid oxide fuel cells and thermochemical CO 2 reduction. Herein, we examined their potential as narrow bandgap semiconductors for use in solar energy harvesting. A cobalt co-doped BCNF, Ba 2 Ca 0.66 Nb 0.68 Fe 0.33 Co 0.33 O 6−δ (BCNFCo), exhibited an optical absorption edge at ∼800 nm, p-type conduction and a distinct photoresponse up to 640 nm while demonstrating high thermochemical stability. A nanocomposite of BCNFCo and g-C 3 N 4 (CN) was prepared via a facile solvent-assisted exfoliation/blending approach using dichlorobenzene and glycerol at a moderate temperature. The exfoliation of g-C 3 N 4 followed by wrapping on perovskite established an effective heterojunction between the materials for charge separation. The conjugated 2D sheets of CN enabled better charge migration resulting in increased photoelectrochemical performance. A blend composed of 40 wt% perovskites and CN performed optimally, whilst achieving a photocurrent density as high as 1.5 mA cm −2 for sunlight-driven water-splitting with a Faradaic efficiency as high as ∼88%.

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Photoluminescence and Raman Spectroscopy Studies of Carbon Nitride Films

Cited by 9 publications

References 25 publications

Engineering the Surface Chemistry and Morphology of Polymeric Carbon Nitrides Towards Greener Heterogeneous Catalysts for Biodiesel Synthesis

Engineering the Surface Chemistry and Morphology of Polymeric Carbon Nitrides Towards Greener Heterogeneous Catalysts for Biodiesel Synthesis

Copper Modified Carbon Nitride as Fluorescence Sensor for Nitrate Ions

Water-splitting photoelectrodes consisting of heterojunctions of carbon nitride with a p-type low bandgap double perovskite oxide

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