title: Charge Modulation in Graphitic Carbon Nitride as a Switchable Approach to High-Capacity Hydrogen Storage.
abstract: Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials.
authors.affiliation: Integrated Materials Design Centre (IMDC), School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Xin
authors.initials: X
authors.lastname: Tan
authors.affiliation: Integrated Materials Design Centre (IMDC), School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Liangzhi
authors.initials: L
authors.lastname: Kou
authors.affiliation: Integrated Materials Design Centre (IMDC), School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Hassan A
authors.initials: HA
authors.lastname: Tahini
authors.affiliation: Integrated Materials Design Centre (IMDC), School of Chemical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia. sean.smith@unsw.edu.au.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Smith
mesh_terms: D000327:Adsorption; D004553:Electric Conductivity; D006108:Graphite / Q000737:chemistry*; D006859:Hydrogen / Q000302:isolation & purification*; D049329:Nanostructures / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry*; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D009570:Nitriles; C011206:cyanogen; D006108:Graphite; D006859:Hydrogen
keywords: carbon nitride; charge modulation; density-functional calc.; electrocatalysis; hydrogen storage