Dissociative chemisorption of hydrogen molecules on defective graphene-supported aluminium clusters: a computational study

Kumar, Deepak; Govindaraja, Thillai; Krishnamurty, Saïlaja; Selvaraj, Kaliaperumal; Pal, Sourav

doi:10.1039/c8cp05711g

Cited by 10 publications

(7 citation statements)

References 50 publications

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“…1045 The first step in H-spillover on TM particles is to dissociate hydrogen molecules. Although several metals or semimetals have been investigated (Ni, 350,1035 Ti, 350,558,1046 V, 1047 Rh, 97,558 Cu, 1048 Al, 613 ), Pd and Pt are the most studied. The dissociative chemisorption of H 2 on Pt and Pd particles is generally easy and is accompanied by the formation of strong M−H bonds.…”

Section: Methylene Blue Photodegradationmentioning

confidence: 99%

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts

2019

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Fermi level in vii) are shown in purple in ii)-vi) with an iso-value of ±0.003 a.u. Reprinted with permission from ref 57 . Copyright 2014 from the Royal Society of Chemistry; b) Molecular model of a corannulene-like element functionalized with three carboxylic groups from two different perspectives in the cpk representation (on the left). The final structure (190 elements in a cubic cell of 60 Å in size) obtained from random packing of the individual elements (on the right). Cyan: carbon, red: oxygen, white: hydrogen. Reprinted with permission from ref 59 Copyright 2017 from Elsevier; c) Side-views of Ru13 adsorbed on Gr-DV-2COOH site before (on left panel) and after a proton jump (right panel). C atoms are in black, O in red, H in with white and Ru in mocha. Reprinted with permission from ref 60 Copyright 2014 from Elsevier; and d) Spin-density projection in µB/a.u. 2 on the graphene plane around i) the hydrogen chemisorption defect (∆) and ii) the vacancy defect in the a sublattice. Carbon atoms corresponding to the a sublattice (o) and to the b sublattice (•) are distinguished. Simulated STM images of the defects are shown in iii) and iv), respectively. Reprinted with permission from ref 61 .

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Section: Methylene Blue Photodegradationmentioning

confidence: 99%

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts

2019

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“…Earlier studies have demonstrated that the parallel mode shows higher N–N bond dissociation as compared to the vertical mode of dissociation. , Hence, in this study we restrict to the parallel mode of N 2 adsorption on Mo. The adsorption energies of the N 2 molecule, adsorbed in a parallel mode on a Mo-anchored graphene system are calculated as follows: where, E (system-Mo-N 2 ) represents the energy of the N 2 molecule adsorbed on the catalytic systems.…”

Section: Nomenclature Methodology and Computational Detailsmentioning

confidence: 99%

“…dissociation. 40,41 Hence, in this study we restrict to the parallel mode of N 2 adsorption on Mo. The adsorption energies of the N 2 molecule, adsorbed in a parallel mode on a Mo-anchored graphene system are calculated as follows:…”

Section: ■ Introductionmentioning

confidence: 99%

Dinitrogen Activation on Graphene Anchored Single Atom Catalysts: Local Site Activity or Surface Phenomena

et al. 2019

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Catalysis on two-dimensional (2D) substrates with metal clusters or centers is generally dealt with as a surface phenomenon under the conjecture that the delocalized electron density is the driving force. When single atom catalysts (SACs) are anchored on such materials with delocalized electron density, for instance graphene, the stimulant for catalysis may be either the d-electrons on the metal or the system altogether. To understand the contributing factors of catalysis on such systems, a case study of dinitrogen (N 2 ) activation on Mo anchored graphene has been made by employing periodic and finite models of graphene. The periodic model represents a continuum of SACs anchored periodically on graphene, while the finite models are graphene nanoflakes of varying sizes and edge orientations. In addition to the physical aspects, such as size/finiteness of graphene, the influence of varying chemical compositions of the substrate on the activity is also evaluated by doping graphene with different B and N concentrations. This study, while clearly bringing out the connotation of regulating atomic composition of graphene substrate for dinitrogen activation, also surprisingly unveils the relative insignificance of varying the size and edge effects of the substrate. These features are highlighted through an analysis of red shift in the N−N stretching frequency, charge transfer to dinitrogen from the catalytic system, and structural and electronic characteristics of the catalytic system. The total and projected density of states plots reveal hybridization between the metal d orbitals and the p orbitals of carbon and nitrogen in the valence band. On the other hand, the frontier molecular orbital analysis also depicts a strong chemisorption of dinitrogen with the metal−graphene supports on account of direct hybridization between the d orbitals of the supported metal atom and the p orbitals of dinitrogen. The Bader and Loẅdin charge distribution on the adsorbed dinitrogen in periodic and finite models shows the preeminence of local site over the surface activity.

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“…Chemical modification of graphene sheet (presence of dopants in graphene sheet) is known to enhance its ability to donate electrons for catalytic reaction by modulating the donor acceptor properties of the graphene sheets. [60] Such site specific introduction of dopants with precise atomic regulation on graphene based systems is experimentally viable through state of art methodologies. [61] Hence, we introduce nitrogen and boron as dopants at the centre of the sheet with increasing concentration.…”

Section: Computational Detailsmentioning

confidence: 99%

“…This pristine graphene sheets (Pr) are further doped with N and B atoms to obtain chemically modified graphene sheets as shown in Figures 1(b) to 1(h). Chemical modification of graphene sheet (presence of dopants in graphene sheet) is known to enhance its ability to donate electrons for catalytic reaction by modulating the donor acceptor properties of the graphene sheets [60] . Such site specific introduction of dopants with precise atomic regulation on graphene based systems is experimentally viable through state of art methodologies [61] .…”

Section: Computational Detailsmentioning

confidence: 99%

Can Li Atoms Anchored on Boron‐ and Nitrogen‐Doped Graphene Catalyze Dinitrogen Molecules to Ammonia? A DFT Study

et al. 2023

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The most successful electrochemical conversion of ammonia from dinitrogen molecule reported to date is through a Li mediated mechanism. In the framework of the above fact and that Li anchored graphene is an experimentally feasible system, the present work is a computational experiment to identify the potential of Li anchored graphene as a catalyst for N2 to NH3 conversion as a function of (a) minimum number of Li atoms needed for anchoring on graphene sheets and (b) the role of chemical modification of graphene surfaces. The studies bring forth an understanding that Li anchored graphene sheets are potential catalysts for ammonia conversion with preferential adsorption of N2 through end‐on configuration on Li atoms anchored on doped and pristine graphene surfaces. This mode of adsorption being characteristic of Nitrogen Reduction Reaction (NRR) through enzymatic pathway, examination of the same followed by analysis of electronic properties demonstrates that tri‐Li atoms (Tri Atom Catalysts, TACs) are more efficient as catalysts for NRR as compared to two Li atoms (Di Atom Catalysts, DACs). Either way, the rate determining step was found to be *NH2→*NH3 step (mixed pathway) with ΔGmax=1.02 eV and *NH2−*NH3→*NH2 step (enzymatic pathway) with ΔGmax=1.11 eV for 1B doped TAC and DAC on graphene sheet, respectively. Consequently, this work identifies the viability of Li anchored graphene based 2‐D sheets as hetero‐atom catalyst for NRR.

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Dissociative chemisorption of hydrogen molecules on defective graphene-supported aluminium clusters: a computational study

Abstract: Using periodic density functional theory-based calculations, in the present study, we address the chemical bonding between aluminium clusters (Aln, n = 4–8 and 13) and monovacant defective graphene.

Cited by 10 publications

References 50 publications

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts

Dinitrogen Activation on Graphene Anchored Single Atom Catalysts: Local Site Activity or Surface Phenomena

Can Li Atoms Anchored on Boron‐ and Nitrogen‐Doped Graphene Catalyze Dinitrogen Molecules to Ammonia? A DFT Study

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