Reactive atom synthesis and characterization of C3N4 crystalline films

Li, Y. G.; Wee, Andrew Thye Shen; Huan, C. H. A.; Li, W. S.; Pan, Jisheng

doi:10.1002/(sici)1096-9918(199908)28:1<221::aid-sia581>3.0.co;2-a

Cited by 10 publications

(1 citation statement)

References 23 publications

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“…In the spectra of the TiO 2 @ x CN materials, besides the O–H band, the C–N stretching vibration band at 1612 cm –1 and aromatic C–N stretching vibration bands at 1387 and 1311 cm –1 were observed. They indicate the presence of carbon nitride species. − …”

Section: Results and Discussionmentioning

confidence: 99%

Tuning the Metal–Support Interaction and Enhancing the Stability of Titania-Supported Cobalt Fischer–Tropsch Catalysts via Carbon Nitride Coating

et al. 2020

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Supported metal catalysts have found numerous applications in many catalytic reactions, including Fischer-Tropsch synthesis. Metal dispersion, metal reducibility, catalytic performance and catalyst stability are usually strongly affected by the interaction of active phase and support. A strong metal support interaction has been previously reported for titania supported catalysts.In this work, a series of titania supported cobalt catalysts promoted via deposition of a layer of carbon nitride were prepared, characterized and tested in Fischer-Tropsch synthesis. The catalytic performance of freshly activated catalysts was an interplay of cobalt dispersion and reducibility. Deposition of carbon nitride on the surface of titania resulted in a noticeable enhancement of cobalt dispersion, while it hindered to some extent cobalt reducibility. The non-promoted cobalt catalysts exhibited noticeable deactivation in Fischer-Tropsch synthesis. The catalyst deactivation was due to the progressive encapsulation of cobalt active phase by TiO 2 during the reaction. A carbon nitride layer on the TiO 2 surface stabilized cobalt nanoparticles and prevented encapsulation of active sites by TiO 2 species. The stability was significantly enhanced on all titania supported cobalt catalysts promoted with carbon nitride.

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Section: Results and Discussionmentioning

confidence: 99%

Tuning the Metal–Support Interaction and Enhancing the Stability of Titania-Supported Cobalt Fischer–Tropsch Catalysts via Carbon Nitride Coating

et al. 2020

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Unique Single‐Crystalline Beta Carbon Nitride Nanorods

et al. 2003

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The discovery of the carbon nanotube has opened a challenging new field in materials, solid-state physics, and chemistry, offering a wide perspective for many possible applications.[1] The successful synthesis of functional ceramic micro-or nanostructures such as BN, [2,3] WS 2 , [4] MoS 2 , [5] In 2 O 3 , [6] TiO 2 , [7] and so forth has been reported. The theoretical prediction of a super-hard carbon nitride solid of composition C 3 N 4 (space group P6 3 /m) by Liu and Cohen [8] has directed the efforts of many experimental groups to synthesize this compound.[9±14] It has been extensively claimed that the carbon nitride compound could be formed in thin amorphous films by several methods such as shock-wave compression technology, pyrolysis of high nitrogen content precursors, diode sputtering, solvothermal preparation, pulsed laser ablation, and ion implantation. The hypothetical b-C 3 N 4 has the same crystal structure as b-Si 3 N 4 , with a hexagonal network of tetrahedrally (sp 3 ) bonded carbon and trigonal planar nitrogen (sp 2 ). Besides its predicted hardness, carbon nitride is also considered to be very promising in the fields of tribological and wear-resistance coating and optical and electronic engineering. [15±19] Although extensive studies on the synthesis and the characterization of carbon nitride materials have been reported, so far the nitrogen concentration of the formed carbon nitrogen compound is usually below the ideal composition for C 3 N 4 . Furthermore, the bonding between C and N tends to be of sp 2 -type character. An appropriate synthetic route to obtain the C 3 N 4 solid is still unknown. The difficulties in the synthesis of hard carbon nitrides are very likely related to their low thermodynamic stability with respect to the elements (C and N), indicated by a positive value of the enthalpies of formation. [20] Therefore, it will be particularly important to find effective and low-cost methods for synthesizing carbon nitride single crystals with a chemical composition of 3:4 for C/N. With this aim in view, we have recently succeeded for the first time in synthesizing single crystal b-C 3 N 4 nanorods in gram quantities via a simple route. As is known, the mechanochemical reaction may offer a possible method for materials synthesis under non-equilibrium condition with several advantages over conventional methods such as the production of non-aggregate and uniform particles in the nanometer scale range. [21,22] It may be used to drive a wide range of chemical reactions and can be performed under a controlled atmosphere to initiate solid±solid and solid±gas reactions to obtain special phases that could only be synthesized under extreme conditions such as high pressure and high temperature (HPHT), thus providing a low-cost method for synthesizing carbon nitride crystal. In this communication, nanostructured porous amorphous carbon powders with a high surface area and structural defects were firstly obtained by a high-energy mechanical process, then they were continually high-en...

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X‐ray photoelectron spectroscopy study of carbon nitride coatings deposited by IR laser ablation in a remote nitrogen plasma atmosphere

Jama¹,

Khawwam²,

Loir³

et al. 2001

Surface & Interface Analysis

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The reactive pulsed laser deposition technique was used to deposit carbon nitride .CN x / coatings on a silicon substrate. In this process, an infrared transversely excited atmospheric pressure CO 2 laser ablation of a graphite target in a remote nitrogen plasma afterglow was used to provide simultaneously both carbonand nitrogen-containing species. Evidence of different CN bonding configurations has been observed in the deposited coatings. For nitrogen pressures (P N 2 ) of ≥700 Pa there is an increase in the contribution of sp 2 carbon atoms that is associated with graphitization of the CN x coatings. For P N 2 increasing from zero to 100 Pa, the comparison between XPS core-level and valence band spectra of the CN x coatings shows good correlation between the p-derived states (C 2p electrons) of C-C p bonds in the valence band and the sp 2 carbon atom concentration deduced from the C 1s spectra.The progressive positive contribution of nitrogen lone pair electrons to the valence band is consistent with the increase of the N-C sp 3 contribution with P N 2 . The decrease in the sp 2 carbon atom contribution is associated with the increase of the nitrogen concentration in the coatings.

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Reactive atom synthesis and characterization of C3N4 crystalline films

Cited by 10 publications

References 23 publications

Tuning the Metal–Support Interaction and Enhancing the Stability of Titania-Supported Cobalt Fischer–Tropsch Catalysts via Carbon Nitride Coating

Tuning the Metal–Support Interaction and Enhancing the Stability of Titania-Supported Cobalt Fischer–Tropsch Catalysts via Carbon Nitride Coating

Unique Single‐Crystalline Beta Carbon Nitride Nanorods

X‐ray photoelectron spectroscopy study of carbon nitride coatings deposited by IR laser ablation in a remote nitrogen plasma atmosphere

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