Charge-Controlled Switchable CO₂ Capture on Boron Nitride Nanomaterials

Abstract

Increasing concerns about the atmospheric CO2 concentration and its impact on the environment are motivating researchers to discover new materials and technologies for efficient CO2 capture and conversion. Here, we report a study of the adsorption of CO2, CH4, and H2 on boron nitride (BN) nanosheets and nanotubes (NTs) with different charge states. The results show that the process of CO2 capture/release can be simply controlled by switching on/off the charges carried by BN nanomaterials. CO2 molecules form weak interactions with uncharged BN nanomaterials and are weakly adsorbed. When extra electrons are introduced to these nanomaterials (i.e., when they are negatively charged), CO2 molecules become tightly bound and strongly adsorbed. Once the electrons are removed, CO2 molecules spontaneously desorb from BN absorbents. In addition, these negatively charged BN nanosorbents show high selectivity for separating CO2 from its mixtures with CH4 and/or H2. Our study demonstrates that BN nanomaterials are excellent absorbents for controllable, highly selective, and reversible capture and release of CO2. In addition, the charge density applied in this study is of the order of 1013 cm-2 of BN nanomaterials and can be easily realized experimentally. 2013 American Chemical Society. ABSTRACT:Increasing concerns about the atmospheric CO 2 concentration and its impact on the environment are motivating researchers to discover new materials and technologies for efficient CO 2 capture and conversion. Here, we report a study of the adsorption of CO 2 , CH 4 and H 2 on boron nitride (BN) nanosheets and nanotubes (NTs) with different charge states. The results show that the process of CO 2 capture/release can be simply controlled by switching on/off the charges carried by BN nanomaterials. CO 2 molecules form weak interactions with uncharged BN nanomaterials and are weakly adsorbed. When extra electrons are introduced to these nanomaterials (i.e. when they are negatively charged), CO 2 molecules become tightly bound and strongly adsorbed. Once the electrons are removed, CO 2 molecules spontaneously desorb from BN absorbents. In addition, these negatively charged BN nano-sorbents show high selectivity for separating CO 2 from its mixtures with CH 4 and/or H 2 . Our study demonstrates that BN nanomaterials are excellent absorbents for controllable, highly selective, and reversible capture and release of CO 2. In addition, the charge density applied in this study is of the order of 10 13 cm -2 of BN nanomaterials, and can be easily realized experimentally.

Covalent Functionalization of Boron Nitride Nanotubes via Reduction Chemistry

“…We also performed Bader charge analysis 35 and computed the charge difference, Δq = q C r À q C n , where q C r and q C n are the total charge on the C atom in • CH 3 from reduced and neutral complexes, respectively, which was found to be 0.47e.I n contrast, for the CNT case, Δq was estimated to be 0.03e, which indicates that the extra electron is delocalized over the CNT surface and does not particularly contribute to the new CÀC bond formation, resulting in only a small increase of their binding energy toward • CH 3 upon reduction. For BNNTs the valence electrons on tube surface are localized around N atoms (Figure 1b), and, therefore, the excess electrons likely fill the empty p orbitals of B atoms 36 and are able to form a strong covalent bond together with the unpaired electrons from the radical. The empty B atom sites, which serve as the localization sites for the excess electrons, make reductive functionalization of BNNTs an efficient route to achieve covalent chemistry on B sites.…”

In-plane graphene/boron-nitride heterostructures as an efficient metal-free electrocatalyst for the oxygen reduction reaction

“…This method has been used to successfully determine the interactions between some gases and boron nitride nanotubes, boron nitride nanosheets, boron carbon nanotubes, and boron nanomaterials. [45][46][47][48] The self-consistent field (SCF) procedure was used with a convergence threshold of 10 -6 au on energy and electron density. The direct inversion of the iterative subspace technique developed by Pulay is used with a subspace size 6 to speed up SCF convergence on these systems.…”

Ambient Scalable Synthesis of Surfactant-Free Thermoelectric CuAgSe Nanoparticles with Reversible Metallic-n-p Conductivity Transition

“…[23][24] An all electrons double numerical atomic orbital augmented by dpolarization functions (DNP) was used as basis set, which has been successfully used to determine the electronic structures of nanomaterials. 25 The calculation models were built according to the experimental lattice parameters. [26][27] The electronic Brillouin zone was sampled by using a MonkhorstPack grid of sample spacing 0.002Å -1 .…”