Electronic Structures of Porous Graphene, BN, and BC2N Sheets with One- and Two-Hydrogen Passivations from First Principles
04 Mar 2011-Journal of Physical Chemistry C (American Chemical Society)-Vol. 115, Iss: 13, pp 5334-5343
TL;DR: In this article, the structural and electronic properties of monolayer porous graphene (C), BN, and BC2N sheets with one-hydrogen passivation were investigated. But the porous BN sheet has a larger band gap than the porous C one, whereas the porous BC 2N sheets have variable band gaps depending on the atomic arrangements of B, C and N atoms.
Abstract: Using first-principles calculations, we investigate the structural and electronic properties of monolayer porous graphene (C), BN, and BC2N sheets. All the porous C, BN, and BC2N sheets with one-hydrogen passivation exhibit direct-band-gap semiconducting behaviors. The porous BN sheet has a larger band gap than the porous C one, whereas the porous BC2N sheets have variable band gaps depending on the atomic arrangements of B, C, and N atoms. The stablest conformation of porous BC2N sheets is composed of C and BN hexagons, whereas with two-hydrogen passivation, it becomes the structure containing continuous BN and interrupted C zigzag lines. Furthermore, due to the sp3 hybridization of the edge atoms, the two-hydrogen passivation induces the changes of band gaps as well as direct-to-indirect band-gap transitions in all the porous sheets. We also find that it is more possible to form the porous C and BC2N structures in experiments than the porous BN ones. Our studies demonstrate that the porous C, BN, and BC...
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TL;DR: The structural basics, spectroscopic signatures, and physical properties of the 2D BN nanostructures are discussed and various top-down and bottom-up preparation methodologies are reviewed in detail.
Abstract: The recent surge in graphene research has stimulated interest in the investigation of various 2-dimensional (2D) nanomaterials. Among these materials, the 2D boron nitride (BN) nanostructures are in a unique position. This is because they are the isoelectric analogs to graphene structures and share very similar structural characteristics and many physical properties except for the large band gap. The main forms of the 2D BN nanostructures include nanosheets (BNNSs), nanoribbons (BNNRs), and nanomeshes (BNNMs). BNNRs are essentially BNNSs with narrow widths in which the edge effects become significant; BNNMs are also variations of BNNSs, which are supported on certain metal substrates where strong interactions and the lattice mismatch between the substrate and the nanosheet result in periodic shallow regions on the nanosheet surface. Recently, the hybrids of 2D BN nanostructures with graphene, in the form of either in-plane hybrids or inter-plane heterolayers, have also drawn much attention. In particular, the BNNS–graphene heterolayer architectures are finding important electronic applications as BNNSs may serve as excellent dielectric substrates or separation layers for graphene electronic devices. In this article, we first discuss the structural basics, spectroscopic signatures, and physical properties of the 2D BN nanostructures. Then, various top-down and bottom-up preparation methodologies are reviewed in detail. Several sections are dedicated to the preparation of BNNRs, BNNMs, and BNNS–graphene hybrids, respectively. Following some more discussions on the applications of these unique materials, the article is concluded with a summary and perspectives of this exciting new field.
764 citations
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TL;DR: The most recent progress on graphene-related nanomaterials, including doped graphene and derived graphene nanoribbons, graphene oxide, graphane, fluorographene, graphyne, graphdiyne, and porous graphene are discussed, and tuning their stability, electronic and magnetic properties by chemical functionalization is emphasized.
Abstract: In this review, we discuss the most recent progress on graphene-related nanomaterials, including doped graphene and derived graphene nanoribbons, graphene oxide, graphane, fluorographene, graphyne, graphdiyne, and porous graphene, from both experimental and theoretical perspectives, and emphasize tuning their stability, electronic and magnetic properties by chemical functionalization.
609 citations
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TL;DR: High-throughput screening of catalysts for the NRR among a series of transition metal atoms supported on a defective hexagonal boron nitride (h-BN) nanosheet is performed through spin-polarized density functional theory (DFT) computations, and V@BN was found to exhibit outstanding catalytic activity via an enzymatic pathway with an extremely low overpotential.
Abstract: The electrocatalytic reduction of naturally abundant N2 to NH3 is an attractive approach to replace the Haber–Bosch nitrogen-fixation process that causes enormous energy consumption and greenhouse gas emissions. However, designing high-performance catalysts toward the electrocatalytic N2 reduction reaction (eNRR) remains one of the greatest challenges in this area. Herein, high-throughput screening of catalysts for the NRR among a series of transition metal atoms supported on a defective hexagonal boron nitride (h-BN) nanosheet is performed through spin-polarized density functional theory (DFT) computations. Strikingly, among the 18 candidates, the V/Tc atom anchored on a defective h-BN monolayer (V@BN and Tc@BN) showed good NRR activity with relatively low onset potentials. Particularly, V@BN was found to exhibit outstanding catalytic activity for the NRR via an enzymatic pathway with an extremely low overpotential of 0.25 V. The value is significantly lower than that on the Ru (0001) stepped surface that has the best NRR catalytic performance among bulk metal catalysts. The novel NRR activity of V@BN is attributed to the enhanced electrical conductivity due to V-doping, the “donation–backdonation” process for N2 activation, and the highly centralized spin-polarization on the V atom. This work not only provides a quite promising catalyst for the NRR but also provides new insights for the rational design of single-atom NRR catalysts.
84 citations
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TL;DR: Li et al. as discussed by the authors proposed a porous monolayer boron nitride, named p-BN, based on first-principles calculations, which can exhibit strong adsorption in the visible light region.
Abstract: Hydrogen is a highly appealing renewable energy resource, while hydrogen generation and storage for practical applications remain a great challenge at present. Herein, porous monolayer boron nitride, named p-BN, is proposed based on first-principles calculations. Compared with the perfect h-BN, the band gap of p-BN is decreased by about 0.7 eV. Interestingly, the band gap of p-BN can be easily modulated, and the C-doped p-BN possesses a moderate band gap of 1.8 eV, which can exhibit strong adsorption in the visible light region. Additionally, p-BN exhibits higher ability in hydrogen storage than h-BN, due to its large specific surface area. The adsorption energy of hydrogen on p-BN can be further improved by Li decoration. The hydrogen storage on one side of the Li-decorated p-BN reaches a maximum of 7.5 wt%, with an adsorption energy of 160 meV. Consequently, p-BN has great potential to be utilized in both hydrogen generation and storage for practical applications.
76 citations
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TL;DR: In this paper, the structural and chemical properties of functionalised hexagonal boron nitride (h-BN) materials as well as their energy-related applications are surveyed.
Abstract: Energy conversion and storage materials have received wide attention as fossil fuels are gradually running out and climate change is looming. Hexagonal boron nitride (h-BN) is not usually considered as a promising material for these applications because of its chemical inertness and poor electronic conductivity. However, through physical and chemical modification, h-BN shows tuneable properties that make it interesting for energy conversion and storage. The excellent stability and environmentally benign nature make h-BN derived materials particularly attractive for green energy applications. In this review, we survey the studies on structural and chemical properties of functionalised h-BN materials as well as their energy-related applications. Research progress in energy conversion and utilisation such as electrochemical catalysis, photocatalysis, and selective oxidative dehydrogenation is reviewed. Energy storage applications including rechargeable batteries, supercapacitors, and hydrogen storage are also presented. Finally, we discuss the future and challenge for functionalised h-BN in energy conversion and storage.
74 citations
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