On the role of metal atom doping in hematite for improved photoelectrochemical properties: a comparison study

RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 101745-101751 ◽  
Author(s):  
Jinzhan Su ◽  
Jian Wang ◽  
Cong Liu ◽  
Bo Feng ◽  
Yubin Chen ◽  
...  
Keyword(s):  
Metal Atom ◽  
Photoelectrochemical Properties ◽  
Comparison Study ◽  
Systematic Comparison ◽  
Metal Atoms ◽  
Element Doping ◽  
Metal Element

A systematic comparison study of various metal atoms doped hematites was performed to look into the effect of metal element doping on the photoelectrochemical (PEC) properties of hematite photoelectrodes.

scholarly journals Potential Energy Surfaces for Reactions of X Metal Atoms (X = Cu, Zn, Cd, Ga, Al, Au, or Hg) with YH4 Molecules (Y = C, Si, or Ge) and Transition Probabilities at Avoided Crossings in Some Cases

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Octavio Novaro ◽  
María del Alba Pacheco-Blas ◽  
Juan Horacio Pacheco-Sánchez
Keyword(s):  
Excited State ◽  
Excited States ◽  
Metal Atom ◽  
Potential Energy Surfaces ◽  
Transition Probabilities ◽  
Metal Atoms ◽  
Avoided Crossings ◽  
Reaction Barriers ◽  
Energy Surfaces

We review ab initio studies based on quantum mechanics on the most important mechanisms of reaction leading to the C–H, Si–H, and Ge–H bond breaking of methane, silane, and germane, respectively, by a metal atom in the lowest states in symmetry: X(2nd excited state, 1st excited state and ground state) + YH4 H3XYH H + XYH3 and XH + YH3. with X = Au, Zn, Cd, Hg, Al, and G, and Y = C, Si, and Ge. Important issues considered here are (a) the role that the occupation of the d-, s-, or p-shells of the metal atom plays in the interactions with a methane or silane or germane molecule, (b) the role of either singlet or doublet excited states of metals on the reaction barriers, and (c) the role of transition probabilities for different families of reacting metals with these gases, using the H–X–Y angle as a reaction coordinate. The breaking of the Y–H bond of YH4 is useful in the production of amorphous hydrogenated films, necessary in several fields of industry.

scholarly journals Reducing the irreducible: Dispersed metal atoms facilitate reduction of irreducible oxides.

2021 ◽  
Author(s):  
Ville Korpelin ◽  
Marko M. Melander ◽  
Karoliina Honkala
Keyword(s):  
Metal Atom ◽  
Single Atom ◽  
Strong Interactions ◽  
Theoretical Understanding ◽  
Precise Control ◽  
Orbital Interactions ◽  
Metal Atoms ◽  
Catalytically Active ◽  
Reducible Oxides

Oxide reducibility is a central concept quantifying the role of the support in catalysis. While reducible oxides are often considered catalytically active, irreducible oxides are seen as inert supports. Enhancing the reducibility of irreducible oxides has, however, emerged as an effective way to increase their catalytic activity while retaining their inherent thermal stability. In this work, we focus on the prospect of using single metal atoms to increase the reducibility of a prototypical irreducible oxide, zirconia. Based on extensive self-consistent DFT+U calculations, we demonstrate that single metal atoms significantly improve and tune the surface reducibility of zirconia. Detailed analysis of the observed single atom induced reducibility allows us to attribute the enhanced reducibility to strong interactions between the metal atom and the electrons trapped in the vacancy, and d-p orbital interactions between the metal atom and oxygen. This analysis enables transferring the obtained theoretical understanding to other irreducible oxides as well. The detailed understanding of how oxide reducibility can be tuned offers precise control over the catalytic properties of metal--oxides.

scholarly journals Role of Chemical Structure of Support in Enhancing the Catalytic Activity of a Single Atom Catalyst Toward NRR: A Computational Study

2021 ◽  
Vol 9 ◽  
Author(s):  
Thillai Govindaraja Senthamaraikannan ◽  
Selvaraj Kaliaperumal ◽  
Sailaja Krishnamurty
Keyword(s):  
Metal Atom ◽  
Density Functional ◽  
Computational Study ◽  
Molecular Nitrogen ◽  
Red Shift ◽  
Single Atom ◽  
Metal Atoms ◽  
Doped Graphene ◽  
Adsorption Energies

Using the periodic density functional theory–based methodology, we propose a potential catalytic system for dinitrogen activation, viz., single metal atoms (Mo, Fe, and V) supported on graphene-based sheets. Graphene-based sheets show an excellent potential toward the anchoring of single atoms on them (Mo, Fe, and V) with adsorption energies ranging between 1.048 and 10.893 eV. Factors such as defects and BN doping are noted to enhance the adsorption energies of single metal atoms on the support. The adsorption of a dinitrogen molecule on metal atom–anchored graphene-based supports is seen to be highly favorable, ranging between 0.620 and 2.278 eV. The adsorption is driven through a direct hybridization between the d orbitals of the metal atom (Mo, Fe, and V) on the support and the p orbital of the molecular nitrogen. Noticeably, BN-doped graphene supporting a single metal atom (Mo, Fe, and V) activates the N2 molecule with a red shift in the N–N stretching frequency (1,597 cm−1 as compared to 2,330 cm−1 in the free N2 molecule). This red shift is corroborated by an increase in the N–N bond length (1.23 Å from 1.09 Å) and charge transfer to an N2 molecule from the catalyst.

Ion chemistry of transition metals in hydrocarbon flames. II. Cations of Sc, Ti, V, Cr, and Mn

1988 ◽  
Vol 66 (9) ◽  
pp. 2219-2228 ◽  
Author(s):  
John M. Goodings ◽  
Quang Tran ◽  
Nicholas S. Karellas
Keyword(s):  
Transition Metals ◽  
Metal Atom ◽  
Chemical Ionization ◽  
Metallic Ions ◽  
Ion Chemistry ◽  
Hydrocarbon Flames ◽  
Basic Series ◽  
First Time ◽  
Isomeric Structures

The same fuel-rich, premixed, conical, methane–oxygen flame at 2200 K and atmospheric pressure used for studies of Fe, Co, Ni, Cu, and Zn in Part I (1) is doped with the same concentration (~1 ppm) of Sc, Ti, V, Cr, and Mn to complete the first row of ten transition metals. Metallic ions of these metals and their compounds formed by chemical ionization reactions with H3O+ are observed by sampling the flame through a nozzle into a quadrupole mass spectrometer. Concentration profiles of individual and total cations are measured as a function of distance along the flame axis, and also mass spectra at a fixed point in the burnt gas. If A is the metal atom, the observed ions can be represented by four hydrate series including (a) A+•nH2O, (b) AOH+•nH2O, (c) AO+•nH2O, and (d) AO2H+•nH2O with n = 0–3 or 4, giving a maximum of four ligands around the metal atom. However, alternative isomeric structures are possible for each of the four basic series (e.g. AO+•2H2O ~ A(OH)2+•H2O ~ A(OH)3H+). The ions observed with Cr and Mn, in common with those of Fe, Co, Ni, and Cu, strongly favour series (a). On the other hand, Sc is completely different; the ions of series (c) are dominant. All four series are observed with each of Ti and V. Series (b) dominates for Ti and series (c) for V; ions from series (d) were observed for the first time. The ion chemistry of these metals is discussed in detail with emphasis on the probable chemical ionization reactions responsible for metallic ion formation. The pre-eminent role of proton transfer processes is apparent.

Role of Interfacial Defects in Photoelectrochemical Properties of BiVO4 Coated on ZnO Nanodendrites: X-ray Spectroscopic and Microscopic Investigation

2021 ◽  
Vol 13 (35) ◽  
pp. 41524-41536
Author(s):  
Hsiao-Tsu Wang ◽  
Jau-Wern Chiou ◽  
Kuan-Hung Chen ◽  
Abhijeet R. Shelke ◽  
Chung-Li Dong ◽  
...  
Keyword(s):  
Microscopic Investigation ◽  
Photoelectrochemical Properties ◽  
X Ray ◽  
Interfacial Defects

Hexaruthenium and octaruthenium carbonyl cluster complexes derived from 2-amino-6-methylpyridine — Novel coordination modes for 2-imidopyridines

2006 ◽  
Vol 84 (2) ◽  
pp. 105-110 ◽  
Author(s):  
Javier A Cabeza ◽  
Ignacio del Río ◽  
Pablo García-Álvarez ◽  
Daniel Miguel
Keyword(s):  
Metal Atom ◽  
Cluster Compounds ◽  
Carbonyl Cluster ◽  
Amido Ligands ◽  
Ruthenium Cluster ◽  
Coordination Type ◽  
Metal Atoms ◽  
Pyridine Nitrogen ◽  
Cluster 2 ◽  
Reflux Temperature

The hexanuclear ruthenium cluster [Ru6(µ3-H)2(µ-H)2(µ4-κ2-ampy)2(CO)14] (1) and the octanuclear one [Ru8(µ-H)(µ4-κ2-ampy)3(µ3-κ2-Hampy)(µ-CO)2(CO)15] (2) have been prepared by treating [Ru6(µ3-H)2(µ5-κ2-ampy)(µ-CO)2(CO)14] with 2-amino-6-methylpyridine (H2ampy) in decane at reflux temperature. Their metal atoms are supported by ligands that derive from the activation of one (complex 2) or both N—H bonds (complexes 1 and 2) of the H2ampy amino fragment. Both contain at least one ampy ligand featuring an unprecedented coordination type: the imido N atom caps a triangle of metal atoms while the pyridine nitrogen is attached to an additional metal atom. One of the ampy ligands of cluster 2 also displays another unprecedented coordination type: it caps a distorted square of metal atoms through the imido N atom while the pyridine nitrogen is attached to one of the atoms included in that square.Key words: ruthenium, cluster compounds, amido ligands, imido ligands.

Cyano-Functionalized Porphyrins on Cu(111) from One-Dimensional Wires to Two-Dimensional Molecular Frameworks: On the Role of Co-Deposited Metal Atoms

2020 ◽  
Vol 32 (5) ◽  
pp. 2114-2122
Author(s):  
Alisson Ceccatto dos Santos ◽  
Rodrigo Cezar de Campos Ferreira ◽  
Juan Carlos Moreno-López ◽  
Lucas Barreto ◽  
Michael Lepper ◽  
...  
Keyword(s):  
Two Dimensional ◽  
One Dimensional ◽  
Metal Atoms ◽  
Deposited Metal
Sign in / Sign up

Export Citation Format

Share Document