CO2 Activation on Heterostructures of Bi2O3-Nanocluster Modified TiO2: Promoting the Critical First Step in CO2 Conversion

10.26434/chemrxiv.5917351 ◽

2018 ◽

Author(s):

Michael Nolan

Keyword(s):

Metal Oxide ◽

Density Functional ◽

Initial Step ◽

Difficult Problem ◽

Carbonate Formation ◽

Structural Distortions ◽

Strong Adsorption ◽

Two Factors ◽

Key Steps ◽

Recent Experimental Work

The conversion of CO2 to fuels is of significant importance in enabling the production of sustainable fuels, contributing to alleviating greenhouse gas emissions. While there are a number of key steps required to convert CO2, the initial step of adsorption and activation by the catalyst is critical. Well-known metal oxides such as oxidised TiO2 or CeO2 are unable to promote this step. In addressing this difficult problem, recent experimental work shows the potential for bismuth-containing materials to activate and convert CO2, but the origin of this activity is not yet clear. Additionally, nanostructures can show enhanced activity towards CO2. In this paper we present density functional theory (DFT) simulations of CO2 activation on heterostructured materials composed of extended rutile and anatase TiO2 surfaces modified with nanoclusters with Bi2O3 stoichiometry. These heterostructures show low coordinated Bi sites in the nanoclusters and a valence band edge that is dominated by Bi-O states. These two factors mean that supported Bi2O3 nanoclusters are able to adsorb and activate CO2. Computed adsorption energies lie in the range of -0.54 eV to -1.01 eV. In these strong adsorption modes, CO2 is activated, in which the molecule bends giving O-C-O angles of 126 - 130o and elongation of C-O distances up to 1.28 Å, with no carbonate formation. The electronic properties show a strong CO2-Bi-oxygen interaction that drives the interaction of CO2 to induce the structural distortions. Bi2O3-TiO2 heterostructures can be reduced to form Bi2+ and Ti3+ species. The interaction of CO2 with this electron-rich, reduced system can produce CO directly, reoxidising the heterostructure or form an activated carboxyl species (CO2-) through electron transfer from the heterostructure to CO2. These results highlight that a semiconducting metal oxide modified with suitable metal oxide nanoclusters can activate CO2, thus overcoming the difficulties associated with the difficult first step in CO2 conversion.

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Activation of CO2 at Chromia-Nanocluster-Modified Rutile and Anatase TiO2

10.26434/chemrxiv.6025658.v1 ◽

2018 ◽

Author(s):

Michael Nolan ◽

Marco Fronzi

Keyword(s):

Metal Oxide ◽

Density Functional ◽

Initial Step ◽

Difficult Problem ◽

Anatase Tio2 ◽

Functional Theory ◽

Oxide Support ◽

Structural Distortions ◽

Metal Oxide Support ◽

Dft Simulations

Converting CO2 to fuels is required to enable the production of sustainable fuels and to contribute to alleviating CO2 emissions. In considering conversion of CO2, the initial step of adsorption and activation by the catalyst is crucial. In addressing this difficult problem, we have examined how nanoclusters of reducible metal oxides supported on TiO2 can promote CO2 activation. In this paper we present density functional theory (DFT) simulations of CO2 activation on heterostructures composed of extended rutile and anatase TiO2 surfaces modified with chromia nanoclusters. The heterostructures show non-bulk Cr and O sites in the nanoclusters and an upshifted valence band edge that is dominated by Cr 3d- O 2p interactions. We show that the supported chromia nanoclusters can adsorb and activate CO2 and that activation of CO2 is promoted whether the TiO2 support is oxidised or hydroxylated. Reduced heterostructures, formed by removal of oxygen from the chromia nanocluster, also promote CO2 activation. In the strong CO2 adsorption modes, the molecule bends giving O-C-O angles of 127 - 132o and elongation of C-O distances up to 1.30 Å; no carbonates are formed. The electronic properties show a strong CO2-Cr-O interaction that drives the interaction of CO2 with the nanocluster and induces the structural distortions. These results highlight that a metal oxide support modified with reducible metal oxide nanoclusters can activate CO2, thus helping to overcome difficulties associated with the difficult first step in CO2 conversion.

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Activation of CO2 at Chromia-Nanocluster-Modified Rutile and Anatase TiO2

10.26434/chemrxiv.6025658 ◽

2018 ◽

Author(s):

Michael Nolan ◽

Marco Fronzi

Keyword(s):

Metal Oxide ◽

Density Functional ◽

Initial Step ◽

Difficult Problem ◽

Anatase Tio2 ◽

Functional Theory ◽

Oxide Support ◽

Structural Distortions ◽

Metal Oxide Support ◽

Dft Simulations

Converting CO2 to fuels is required to enable the production of sustainable fuels and to contribute to alleviating CO2 emissions. In considering conversion of CO2, the initial step of adsorption and activation by the catalyst is crucial. In addressing this difficult problem, we have examined how nanoclusters of reducible metal oxides supported on TiO2 can promote CO2 activation. In this paper we present density functional theory (DFT) simulations of CO2 activation on heterostructures composed of extended rutile and anatase TiO2 surfaces modified with chromia nanoclusters. The heterostructures show non-bulk Cr and O sites in the nanoclusters and an upshifted valence band edge that is dominated by Cr 3d- O 2p interactions. We show that the supported chromia nanoclusters can adsorb and activate CO2 and that activation of CO2 is promoted whether the TiO2 support is oxidised or hydroxylated. Reduced heterostructures, formed by removal of oxygen from the chromia nanocluster, also promote CO2 activation. In the strong CO2 adsorption modes, the molecule bends giving O-C-O angles of 127 - 132o and elongation of C-O distances up to 1.30 Å; no carbonates are formed. The electronic properties show a strong CO2-Cr-O interaction that drives the interaction of CO2 with the nanocluster and induces the structural distortions. These results highlight that a metal oxide support modified with reducible metal oxide nanoclusters can activate CO2, thus helping to overcome difficulties associated with the difficult first step in CO2 conversion.

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Study on the adsorption selection of CH$$_4$$ on CuO (110) versus (111) surfaces: a density functional theory study

SN Applied Sciences ◽

10.1007/s42452-021-04386-x ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Long Lin ◽

Linwei Yao ◽

Shaofei Li ◽

Zhengguang Shi ◽

Kun Xie ◽

...

Keyword(s):

Density Functional Theory ◽

Adsorption Capacity ◽

Active Sites ◽

Density Functional ◽

Oxygen Vacancies ◽

Density Functional Theory Calculations ◽

Density Functional Theory Study ◽

Functional Theory ◽

Strong Adsorption ◽

Selection Of

AbstractFinding the active sites of suitable metal oxides is a key prerequisite for detecting CH$$_4$$ 4 . The purpose of the paper is to investigate the adsorption of CH$$_4$$ 4 on intrinsic and oxygen-vacancies CuO (111) and (110) surfaces using density functional theory calculations. The results show that CH$$_4$$ 4 has a strong adsorption energy of −0.370 to 0.391 eV at all site on the CuO (110) surface. The adsorption capacity of CH$$_4$$ 4 on CuO (111) surface is weak, ranging from −0.156 to −0.325 eV. In the surface containing oxygen vacancies, the adsorption capacity of CuO surface to CH$$_4$$ 4 is significantly stronger than that of intrinsic CuO surface. The results indicate that CuO (110) has strong adsorption and charge transfer capacity for CH$$_4$$ 4 , which may provide experimental guidance.

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ADSORPTION OF NANOWOLLASTONITE ON CELLULOSE SURFACE: EFFECTS ON PHYSICAL AND MECHANICAL PROPERTIES OF MEDIUM-DENSITY FIBERBOARD (MDF)

CERNE ◽

10.1590/0104776020162222146 ◽

2016 ◽

Vol 22 (2) ◽

pp. 215-222 ◽

Cited By ~ 13

Author(s):

Hamid Reza Taghiyari ◽

Roya Majidi ◽

Asghar Jahangiri

Keyword(s):

Mechanical Properties ◽

Density Functional ◽

Medium Density Fiberboard ◽

Physical And Mechanical Properties ◽

Mechanical Tests ◽

National Standard ◽

Medium Density ◽

Wood Fibers ◽

Strong Adsorption ◽

Cellulose Surface

ABSTRACT Effects of nanowollastonite (NW) adsorption on cellulose surface were studied on physical and mechanical properties of medium-density fiberboard (MDF) panels; properties were then compared with those of MDF panels without NW-content. The size range of NW was 30-110 nm. The interaction between NW and cellulose was investigated using density functional theory (DFT). Physical and mechanical tests were carried out in accordance with the Iranian National Standard ISIRI 9044 PB Type P2 (compatible with ASTM D1037-99) specifications. Results of DFT simulations showed strong adsorption of NW on cellulose surface. Moreover, mechanical properties demonstrated significant improvement. The improvement was attributed to the strong adsorption of NW on cellulose surface predicted by DFT, adding to the strength and integrity between wood fibers in NW-MDF panels. It was concluded that NW would improve mechanical properties in MDF panels as a wood-composite material, as well as being effective in improving its biological and thermal conductivity.

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Effect of metal atoms on the electronic properties of metal oxide nanoclusters for use in drug delivery applications: a density functional theory study

Molecular Physics ◽

10.1080/00268976.2019.1692150 ◽

2019 ◽

Vol 118 (13) ◽

pp. e1692150 ◽

Cited By ~ 2

Author(s):

Xiaoying Chen ◽

Zhangping Sun ◽

Huanran Zhang ◽

Saeid Onsori

Keyword(s):

Drug Delivery ◽

Density Functional Theory ◽

Metal Oxide ◽

Electronic Properties ◽

Density Functional ◽

Density Functional Theory Study ◽

Functional Theory ◽

Metal Atoms ◽

Drug Delivery Applications

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Interfacial Processes—The Key Steps of Phase Transfer Catalyzed Reactions

Catalysts ◽

10.3390/catal10121436 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1436

Author(s):

Mieczysław Mąkosza ◽

Michał Fedoryński

Keyword(s):

Experimental Evidence ◽

Phase Transfer ◽

Initial Step ◽

Organic Anions ◽

Two Phase ◽

Interfacial Processes ◽

Phase Systems ◽

Catalyzed Reactions ◽

Key Steps

After short historical introduction, interfacial mechanism of phase transfer catalyzed (PTC) reactions of organic anions, induced by aqueous NaOH or KOH in two-phase systems is formulated. Subsequently experimental evidence that supports the interfacial deprotonation as the key initial step of these reactions is presented.

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Reversible spin storage in metal oxide—fullerene heterojunctions

Science Advances ◽

10.1126/sciadv.aax1085 ◽

2020 ◽

Vol 6 (12) ◽

pp. eaax1085 ◽

Cited By ~ 1

Author(s):

T. Moorsom ◽

M. Rogers ◽

I. Scivetti ◽

S. Bandaru ◽

G. Teobaldi ◽

...

Keyword(s):

Metal Oxide ◽

Density Functional ◽

Muon Spin ◽

Magnetic Ordering ◽

Charge Trapping ◽

Energy Shift ◽

Storage Device ◽

Oxide Interface ◽

Independent Evidence ◽

Spin Polarized

We show that hybrid MnOx/C60 heterojunctions can be used to design a storage device for spin-polarized charge: a spin capacitor. Hybridization at the carbon-metal oxide interface leads to spin-polarized charge trapping after an applied voltage or photocurrent. Strong electronic structure changes, including a 1-eV energy shift and spin polarization in the C60 lowest unoccupied molecular orbital, are then revealed by x-ray absorption spectroscopy, in agreement with density functional theory simulations. Muon spin spectroscopy measurements give further independent evidence of local spin ordering and magnetic moments optically/electronically stored at the heterojunctions. These spin-polarized states dissipate when shorting the electrodes. The spin storage decay time is controlled by magnetic ordering at the interface, leading to coherence times of seconds to hours even at room temperature.

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Metal-induced n+/n homojunction for ultrahigh electron mobility transistors

NPG Asia Materials ◽

10.1038/s41427-020-00271-y ◽

2020 ◽

Vol 12 (1) ◽

Author(s):

Ji-Min Park ◽

Hyoung-Do Kim ◽

Hongrae Joh ◽

Seong Cheol Jang ◽

Kyung Park ◽

...

Keyword(s):

Metal Oxide ◽

Field Effect ◽

Density Functional ◽

Metal Layer ◽

Cost Effective ◽

Interface Layer ◽

Field Effect Mobility ◽

High Concentration ◽

Large Area ◽

Electron Mobility Transistors

AbstractA self-organized n+/n homojunction is proposed to achieve ultrahigh performance of thin film transistors (TFTs) based on an amorphous (Zn,Ba)SnO3 (ZBTO) semiconductor with sufficiently limited scattering centers. A deposited Al layer can induce a highly O-deficient (n+) interface layer in the back channel of a-ZBTO without damaging the front channel layer via the formation of a metal-oxide interlayer between the metal and back channel. The n+ layer can significantly improve the field-effect mobility by providing a relatively high concentration of free electrons in the front n-channel ZBTO, where the scattering of carriers is already controlled. In comparison with a Ti layer, the Al metal layer is superior, as confirmed by first-principles density functional theory (DFT) calculations, due to the stronger metal-O bonds, which make it easier to form a metal oxide AlOx interlayer through the removal of oxygen from ZBTO. The field-effect mobility of a-ZBTO with an Al capping layer can reach 153.4 cm2/Vs, which is higher than that of the pristine device, i.e., 20.8 cm2/Vs. This result paves the way for the realization of a cost-effective method for implementing indium-free ZBTO devices in various applications, such as flat panel displays and large-area electronic circuits.

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