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Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture.

Tan X, Kou L, Tahini HA, Smith SC - Sci Rep (2015)

Bottom Line: At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 10(13) cm(-2) or 42.3 wt%.In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2.These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

View Article: PubMed Central - PubMed

Affiliation: Integrated Materials Design Centre (IMDC), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia.

ABSTRACT
Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 10(13) cm(-2) or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

No MeSH data available.


Top (upper) and side (lower) views of (a) a (2 × 2) reconstructed g-C4N3 supercell. The blue and grey balls represent N and C atoms, respectively, and the unit cell of g-C4N3 is indicated by red dot lines. C1 and C2 denote different C atoms in g-C4N3 unit cell. The calculated band structures of (b) a (2 × 2) reconstructed g-C4N3. The blue dashed line denotes the Fermi level. The red and black lines in (b) denote the spin-up and spin-down states, respectively.
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f1: Top (upper) and side (lower) views of (a) a (2 × 2) reconstructed g-C4N3 supercell. The blue and grey balls represent N and C atoms, respectively, and the unit cell of g-C4N3 is indicated by red dot lines. C1 and C2 denote different C atoms in g-C4N3 unit cell. The calculated band structures of (b) a (2 × 2) reconstructed g-C4N3. The blue dashed line denotes the Fermi level. The red and black lines in (b) denote the spin-up and spin-down states, respectively.

Mentions: Since good electrical conductivity and high electron mobility are prerequisite for injecting extra electrons into electrocatalytically switchable CO2 capture materials, we first studied the electronic structures of isolated g-C4N3. The lowest-energy configurations and the calculated band structures of g-C4N3 are shown in Fig. 1. Consistent with previous studies36, g-C4N3 is a (2 × 2) reconstructed structure with half-metallic state. This indicates that g-C4N3 has good electrical conductivity and high electron mobility, which should readily facilitate electron injection/release for electrocatalytically switchable CO2 capture.


Conductive Graphitic Carbon Nitride as an Ideal Material for Electrocatalytically Switchable CO2 Capture.

Tan X, Kou L, Tahini HA, Smith SC - Sci Rep (2015)

Top (upper) and side (lower) views of (a) a (2 × 2) reconstructed g-C4N3 supercell. The blue and grey balls represent N and C atoms, respectively, and the unit cell of g-C4N3 is indicated by red dot lines. C1 and C2 denote different C atoms in g-C4N3 unit cell. The calculated band structures of (b) a (2 × 2) reconstructed g-C4N3. The blue dashed line denotes the Fermi level. The red and black lines in (b) denote the spin-up and spin-down states, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664948&req=5

f1: Top (upper) and side (lower) views of (a) a (2 × 2) reconstructed g-C4N3 supercell. The blue and grey balls represent N and C atoms, respectively, and the unit cell of g-C4N3 is indicated by red dot lines. C1 and C2 denote different C atoms in g-C4N3 unit cell. The calculated band structures of (b) a (2 × 2) reconstructed g-C4N3. The blue dashed line denotes the Fermi level. The red and black lines in (b) denote the spin-up and spin-down states, respectively.
Mentions: Since good electrical conductivity and high electron mobility are prerequisite for injecting extra electrons into electrocatalytically switchable CO2 capture materials, we first studied the electronic structures of isolated g-C4N3. The lowest-energy configurations and the calculated band structures of g-C4N3 are shown in Fig. 1. Consistent with previous studies36, g-C4N3 is a (2 × 2) reconstructed structure with half-metallic state. This indicates that g-C4N3 has good electrical conductivity and high electron mobility, which should readily facilitate electron injection/release for electrocatalytically switchable CO2 capture.

Bottom Line: At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 10(13) cm(-2) or 42.3 wt%.In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2.These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

View Article: PubMed Central - PubMed

Affiliation: Integrated Materials Design Centre (IMDC), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia.

ABSTRACT
Good electrical conductivity and high electron mobility of the sorbent materials are prerequisite for electrocatalytically switchable CO2 capture. However, no conductive and easily synthetic sorbent materials are available until now. Here, we examined the possibility of conductive graphitic carbon nitride (g-C4N3) nanosheets as sorbent materials for electrocatalytically switchable CO2 capture. Using first-principle calculations, we found that the adsorption energy of CO2 molecules on g-C4N3 nanosheets can be dramatically enhanced by injecting extra electrons into the adsorbent. At saturation CO2 capture coverage, the negatively charged g-C4N3 nanosheets achieve CO2 capture capacities up to 73.9 × 10(13) cm(-2) or 42.3 wt%. In contrast to other CO2 capture approaches, the process of CO2 capture/release occurs spontaneously without any energy barriers once extra electrons are introduced or removed, and these processes can be simply controlled and reversed by switching on/off the charging voltage. In addition, these negatively charged g-C4N3 nanosheets are highly selective for separating CO2 from mixtures with CH4, H2 and/or N2. These predictions may prove to be instrumental in searching for a new class of experimentally feasible high-capacity CO2 capture materials with ideal thermodynamics and reversibility.

No MeSH data available.