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The superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet.

Li Y, Sun Q - Sci Rep (2014)

Bottom Line: Two-dimensional organometallic sheets containing regularly and separately distributed transition atoms (TMs) have received tremendous attentions due to their flexibility in synthesis, well-defined geometry and the promising applications in hydrogen storage, electronic circuits, quantum Hall effect, and spintronics.Here for the first time we present a study on the superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet proceeding first via Langmuir-Hinshelwood (LH) mechanism and then via Eley-Rideal (ER) mechanism.Compared to the noble metal based catalysts or graphene supported catalysts, our studied system has following unique features: without poisoning effect and clustering problem, having comparable reaction energy barrier for low-temperature oxidation, and low cost for large-scale catalytic CO oxidation in industry.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.

ABSTRACT
Two-dimensional organometallic sheets containing regularly and separately distributed transition atoms (TMs) have received tremendous attentions due to their flexibility in synthesis, well-defined geometry and the promising applications in hydrogen storage, electronic circuits, quantum Hall effect, and spintronics. Here for the first time we present a study on the superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet proceeding first via Langmuir-Hinshelwood (LH) mechanism and then via Eley-Rideal (ER) mechanism. Compared to the noble metal based catalysts or graphene supported catalysts, our studied system has following unique features: without poisoning effect and clustering problem, having comparable reaction energy barrier for low-temperature oxidation, and low cost for large-scale catalytic CO oxidation in industry.

No MeSH data available.


Related in: MedlinePlus

Spin-polarized local density of states (LDOS) projected onto C-O and O1-O2 on a 2D CrPc sheet, as well as the d-projected LDOS of Cr in the IS, TS1, MS and TS2 in the LH step.Black solid curve for the LDOS projected on C-O; blue solid curve for the LDOS projected on O1-O2; red solid curve for the d-projected LDOS of the Cr atom. The corresponding orbital notations are also assigned.
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f6: Spin-polarized local density of states (LDOS) projected onto C-O and O1-O2 on a 2D CrPc sheet, as well as the d-projected LDOS of Cr in the IS, TS1, MS and TS2 in the LH step.Black solid curve for the LDOS projected on C-O; blue solid curve for the LDOS projected on O1-O2; red solid curve for the d-projected LDOS of the Cr atom. The corresponding orbital notations are also assigned.

Mentions: To unveil the microscopic scenario behind the peculiar catalytic activity of the 2D CrPc sheet, we calculated the local density of states projected onto the O1-O2 and the C-O bonds as well as the d-projected LDOS of Cr in IS, TS1, MS and TS2 of the LH step, respectively. As illustrated in Figure 6, the 2π* level of O2 is partially shifted downward upon the adsorption in the IS state due to the notable charge transfer from the Cr atom. In contrast, the 2π* level of CO is still empty because of the paltry amount of charge transfer between CO and Cr. For the O1-O2 species on the 2D CrPc sheet, from IS to TS1, owing to the electronic resonance with CO 2π* state, the 2π* level of O2 is further populated and broadened to hybridize with Cr 3d state to a larger extent. Meanwhile, the 2π* level of CO is also partially populated in the TS1 state. The O1-O2 1π state is elevated and becomes more involved with the Cr 3d state from TS1 to MS to TS2, which is ancillary in weakening the O1-O2 bond. The 2π* level of O1-O2 is gradually elevated upward as a result of the generation of the new C-O2 bond from TS1 to TS2. For the C-O species on the 2D CrPc, because of the end-on adsorption configuration, the 5σ level is shifted upward and strongly hybridized with the Cr 3d level in the whole LH step rather than the 1π level, which is one of the predominant factor in the dissociation of the O1-O2 bond because of the side-on adsorption configuration of O2 molecule. Furthermore, the magnetism of the entire system is quenched at the TS2 state originating from the formation of the nonmagnetic CO2 molecule and O adsorbed 2D CrPc sheet. Overall, mediated by the Cr 3d state, the O1-O2 1π and 2π* level interact strongly with the C-O 5σ and 2π* level. These electronic state resonances lead to the formation of C-O2 bond and the dissociation of O1-O2 bond, accelerating the catalytic elimination of the hazardous CO molecules.


The superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet.

Li Y, Sun Q - Sci Rep (2014)

Spin-polarized local density of states (LDOS) projected onto C-O and O1-O2 on a 2D CrPc sheet, as well as the d-projected LDOS of Cr in the IS, TS1, MS and TS2 in the LH step.Black solid curve for the LDOS projected on C-O; blue solid curve for the LDOS projected on O1-O2; red solid curve for the d-projected LDOS of the Cr atom. The corresponding orbital notations are also assigned.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3924217&req=5

f6: Spin-polarized local density of states (LDOS) projected onto C-O and O1-O2 on a 2D CrPc sheet, as well as the d-projected LDOS of Cr in the IS, TS1, MS and TS2 in the LH step.Black solid curve for the LDOS projected on C-O; blue solid curve for the LDOS projected on O1-O2; red solid curve for the d-projected LDOS of the Cr atom. The corresponding orbital notations are also assigned.
Mentions: To unveil the microscopic scenario behind the peculiar catalytic activity of the 2D CrPc sheet, we calculated the local density of states projected onto the O1-O2 and the C-O bonds as well as the d-projected LDOS of Cr in IS, TS1, MS and TS2 of the LH step, respectively. As illustrated in Figure 6, the 2π* level of O2 is partially shifted downward upon the adsorption in the IS state due to the notable charge transfer from the Cr atom. In contrast, the 2π* level of CO is still empty because of the paltry amount of charge transfer between CO and Cr. For the O1-O2 species on the 2D CrPc sheet, from IS to TS1, owing to the electronic resonance with CO 2π* state, the 2π* level of O2 is further populated and broadened to hybridize with Cr 3d state to a larger extent. Meanwhile, the 2π* level of CO is also partially populated in the TS1 state. The O1-O2 1π state is elevated and becomes more involved with the Cr 3d state from TS1 to MS to TS2, which is ancillary in weakening the O1-O2 bond. The 2π* level of O1-O2 is gradually elevated upward as a result of the generation of the new C-O2 bond from TS1 to TS2. For the C-O species on the 2D CrPc, because of the end-on adsorption configuration, the 5σ level is shifted upward and strongly hybridized with the Cr 3d level in the whole LH step rather than the 1π level, which is one of the predominant factor in the dissociation of the O1-O2 bond because of the side-on adsorption configuration of O2 molecule. Furthermore, the magnetism of the entire system is quenched at the TS2 state originating from the formation of the nonmagnetic CO2 molecule and O adsorbed 2D CrPc sheet. Overall, mediated by the Cr 3d state, the O1-O2 1π and 2π* level interact strongly with the C-O 5σ and 2π* level. These electronic state resonances lead to the formation of C-O2 bond and the dissociation of O1-O2 bond, accelerating the catalytic elimination of the hazardous CO molecules.

Bottom Line: Two-dimensional organometallic sheets containing regularly and separately distributed transition atoms (TMs) have received tremendous attentions due to their flexibility in synthesis, well-defined geometry and the promising applications in hydrogen storage, electronic circuits, quantum Hall effect, and spintronics.Here for the first time we present a study on the superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet proceeding first via Langmuir-Hinshelwood (LH) mechanism and then via Eley-Rideal (ER) mechanism.Compared to the noble metal based catalysts or graphene supported catalysts, our studied system has following unique features: without poisoning effect and clustering problem, having comparable reaction energy barrier for low-temperature oxidation, and low cost for large-scale catalytic CO oxidation in industry.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.

ABSTRACT
Two-dimensional organometallic sheets containing regularly and separately distributed transition atoms (TMs) have received tremendous attentions due to their flexibility in synthesis, well-defined geometry and the promising applications in hydrogen storage, electronic circuits, quantum Hall effect, and spintronics. Here for the first time we present a study on the superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet proceeding first via Langmuir-Hinshelwood (LH) mechanism and then via Eley-Rideal (ER) mechanism. Compared to the noble metal based catalysts or graphene supported catalysts, our studied system has following unique features: without poisoning effect and clustering problem, having comparable reaction energy barrier for low-temperature oxidation, and low cost for large-scale catalytic CO oxidation in industry.

No MeSH data available.


Related in: MedlinePlus