The interaction of NO with Co2+/Co3+ redox centres in CoAPOs catalysts: FTIR and UV-VIS investigations

E. Gianotti; L. Marchese; G. Martra; S. Coluccia

doi:10.1016/S0920-5861(99)00216-3

The interaction of NO with Co²⁺/Co³⁺ redox centres in CoAPOs catalysts: FTIR and UV-VIS investigations

E. Gianotti
, L. Marchese
, G. Martra
, S. Coluccia

Department of Science and Technological Innovation

Research output: Contribution to journal › Conference article › peer-review

Abstract

The interaction of NO with Co²⁺/Co³⁺ redox sites in CoAPO-18 and CoAPO-5 catalysts was studied by means of FTIR and diffuse reflectance UV-Vis spectroscopy both at 298 and 85 K. Two families of Co²⁺ sites were found in the CoAPO-18 structure. (A) Ions in framework [Co²⁺(OH)P], associated with Brønsted acid sites which adsorb NO to produce dinitrosyls absorbing at 1903 and 1834cm^-1; these dinitrosyl complexes are reactive, in that Co²⁺ is oxidized to Co³⁺ and N₂O is formed. (B) Structural defects Co²⁺ (Lewis acid sites) which stabilize dinitrosyls absorbing at 1900 and 1813 cm^-1. The NO adsorption both on reduced and, more significantly, on oxidised CoAPO-18 also leads to the formation of NO₂^δ+ adsorbed species. It was found that the two kinds of dinitrosyl complexes have different reactivity in presence of oxygen. Both families of sites are also present in CoAPO-5 catalysts on which, however, the redox reaction upon NO adsorption does not occur significantly.

Original language	English
Pages (from-to)	547-552
Number of pages	6
Journal	Catalysis Today
Volume	54
Issue number	4
DOIs	https://doi.org/10.1016/S0920-5861(99)00216-3
Publication status	Published - 17 Dec 1999
Event	Proceedings of the 1998 2nd World Congress on Environmental Catalysis 'Environmental Catalysis - Fundamental and Applied NOx Control Studies' - Miami, FL, United States Duration: 15 Nov 1998 → 20 Nov 1998

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title = "The interaction of NO with Co2+/Co3+ redox centres in CoAPOs catalysts: FTIR and UV-VIS investigations",

abstract = "The interaction of NO with Co2+/Co3+ redox sites in CoAPO-18 and CoAPO-5 catalysts was studied by means of FTIR and diffuse reflectance UV-Vis spectroscopy both at 298 and 85 K. Two families of Co2+ sites were found in the CoAPO-18 structure. (A) Ions in framework [Co2+(OH)P], associated with Br{\o}nsted acid sites which adsorb NO to produce dinitrosyls absorbing at 1903 and 1834cm-1; these dinitrosyl complexes are reactive, in that Co2+ is oxidized to Co3+ and N2O is formed. (B) Structural defects Co2+ (Lewis acid sites) which stabilize dinitrosyls absorbing at 1900 and 1813 cm-1. The NO adsorption both on reduced and, more significantly, on oxidised CoAPO-18 also leads to the formation of NO2δ+ adsorbed species. It was found that the two kinds of dinitrosyl complexes have different reactivity in presence of oxygen. Both families of sites are also present in CoAPO-5 catalysts on which, however, the redox reaction upon NO adsorption does not occur significantly.",

author = "E. Gianotti and L. Marchese and G. Martra and S. Coluccia",

year = "1999",

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doi = "10.1016/S0920-5861(99)00216-3",

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journal = "Catalysis Today",

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T1 - The interaction of NO with Co2+/Co3+ redox centres in CoAPOs catalysts

T2 - Proceedings of the 1998 2nd World Congress on Environmental Catalysis 'Environmental Catalysis - Fundamental and Applied NOx Control Studies'

AU - Gianotti, E.

AU - Marchese, L.

AU - Martra, G.

AU - Coluccia, S.

PY - 1999/12/17

Y1 - 1999/12/17

N2 - The interaction of NO with Co2+/Co3+ redox sites in CoAPO-18 and CoAPO-5 catalysts was studied by means of FTIR and diffuse reflectance UV-Vis spectroscopy both at 298 and 85 K. Two families of Co2+ sites were found in the CoAPO-18 structure. (A) Ions in framework [Co2+(OH)P], associated with Brønsted acid sites which adsorb NO to produce dinitrosyls absorbing at 1903 and 1834cm-1; these dinitrosyl complexes are reactive, in that Co2+ is oxidized to Co3+ and N2O is formed. (B) Structural defects Co2+ (Lewis acid sites) which stabilize dinitrosyls absorbing at 1900 and 1813 cm-1. The NO adsorption both on reduced and, more significantly, on oxidised CoAPO-18 also leads to the formation of NO2δ+ adsorbed species. It was found that the two kinds of dinitrosyl complexes have different reactivity in presence of oxygen. Both families of sites are also present in CoAPO-5 catalysts on which, however, the redox reaction upon NO adsorption does not occur significantly.

AB - The interaction of NO with Co2+/Co3+ redox sites in CoAPO-18 and CoAPO-5 catalysts was studied by means of FTIR and diffuse reflectance UV-Vis spectroscopy both at 298 and 85 K. Two families of Co2+ sites were found in the CoAPO-18 structure. (A) Ions in framework [Co2+(OH)P], associated with Brønsted acid sites which adsorb NO to produce dinitrosyls absorbing at 1903 and 1834cm-1; these dinitrosyl complexes are reactive, in that Co2+ is oxidized to Co3+ and N2O is formed. (B) Structural defects Co2+ (Lewis acid sites) which stabilize dinitrosyls absorbing at 1900 and 1813 cm-1. The NO adsorption both on reduced and, more significantly, on oxidised CoAPO-18 also leads to the formation of NO2δ+ adsorbed species. It was found that the two kinds of dinitrosyl complexes have different reactivity in presence of oxygen. Both families of sites are also present in CoAPO-5 catalysts on which, however, the redox reaction upon NO adsorption does not occur significantly.

UR - https://www.scopus.com/pages/publications/0033579671

U2 - 10.1016/S0920-5861(99)00216-3

DO - 10.1016/S0920-5861(99)00216-3

M3 - Conference article

SN - 0920-5861

VL - 54

SP - 547

EP - 552

JO - Catalysis Today

JF - Catalysis Today

IS - 4

Y2 - 15 November 1998 through 20 November 1998

ER -

The interaction of NO with Co²⁺/Co³⁺ redox centres in CoAPOs catalysts: FTIR and UV-VIS investigations

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