Selective Catalytic Reduction of NOx by CO over Doubly Promoted MeMo/Nb2O5 Catalysts (Me = Pt, Ni, or Co)

Nascimento, João Pedro S.; Oton, Lais F.; Oliveira, Alcineia C.; Rodríguez-Aguado, Elena; Rodríguez-Castellón, Enrique; Araujo, Rinaldo S.; Souza, Monique S.; Lang, Rossano

doi:10.3390/catal10091048

Open AccessArticle

Selective Catalytic Reduction of NO_x by CO over Doubly Promoted MeMo/Nb₂O₅ Catalysts (Me = Pt, Ni, or Co)

by

João Pedro S. Nascimento

¹,

Lais F. Oton

¹,

Alcineia C. Oliveira

^1,*,

Elena Rodríguez-Aguado

²,

Enrique Rodríguez-Castellón

²

,

Rinaldo S. Araujo

³,

Monique S. Souza

³ and

Rossano Lang

⁴

¹

Departamento de Química Analítica e Físico-Química, Universidade Federal do Ceará, Campus do Pici, Bloco 940, Fortaleza 60455-760, Ceará, Brazil

²

Departamento de Química Inorgánica, Universidad de Málaga, Facultad de Ciencias, 29071 Málaga, Spain

³

Instituto Federal de Educação-IFCE, Campus de Fortaleza, Av. 13 de Maio 2081, Fortaleza 60455-760, Ceará, Brazil

⁴

Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo-UNIFESP, São José dos Campos-SP 12231-280, Brazil

^*

Author to whom correspondence should be addressed.

Catalysts 2020, 10(9), 1048; https://doi.org/10.3390/catal10091048

Submission received: 10 August 2020 / Revised: 2 September 2020 / Accepted: 8 September 2020 / Published: 11 September 2020

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Abstract

Doubly promoted MeMo/Nb₂O₅ catalysts, in which Me = Pt, Ni, or Co oxides were prepared for the selective catalytic reduction of NO_x by CO reaction (CO-SCR). Comparable chemical, textural, and structural analyses revealed similarities between NiMo and CoMo impregnated on Nb₂O₅, in contrast to PtMo sites, which were not homogeneously dispersed on the support surface. Both the acid function and metal dispersion gave a synergistic effect for CO-SCR at moderate temperatures. The reactivity of PtMo catalysts towards NO_x and CO chemisorption was at low reaction temperatures, whereas the NO_x conversion over CoMo was greatly improved at relatively high temperatures. Careful XPS, NH₃-TPD, and HRTEM analyses confirmed that the large amounts of strong and moderate acid sites from PtO_x entrapped on MoO₃ sites induced high NO_x conversions. NiMo/Nb₂O₅ showed poor performance in all conditions. Poisoning of the MeMo sites with water vapor or SO₂ (or both) provoked the decline of the NO_x conversions over NiMo and PtMo sites, whereas the structure of CoMo ones remained very active with a maximum NO_x conversion of 70% at 350 °C for 24 h of reaction. This was due to the interaction of the Co³⁺/Co²⁺ and Mo⁶⁺ actives sites and the weak strength Lewis acid Nb⁵⁺ ones, as well.

Keywords: Nb₂O₅; catalyst; synergistic effect; NO_x; CO-SCR

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MDPI and ACS Style

Nascimento, J.P.S.; Oton, L.F.; Oliveira, A.C.; Rodríguez-Aguado, E.; Rodríguez-Castellón, E.; Araujo, R.S.; Souza, M.S.; Lang, R. Selective Catalytic Reduction of NO_x by CO over Doubly Promoted MeMo/Nb₂O₅ Catalysts (Me = Pt, Ni, or Co). Catalysts 2020, 10, 1048. https://doi.org/10.3390/catal10091048

AMA Style

Nascimento JPS, Oton LF, Oliveira AC, Rodríguez-Aguado E, Rodríguez-Castellón E, Araujo RS, Souza MS, Lang R. Selective Catalytic Reduction of NO_x by CO over Doubly Promoted MeMo/Nb₂O₅ Catalysts (Me = Pt, Ni, or Co). Catalysts. 2020; 10(9):1048. https://doi.org/10.3390/catal10091048

Chicago/Turabian Style

Nascimento, João Pedro S., Lais F. Oton, Alcineia C. Oliveira, Elena Rodríguez-Aguado, Enrique Rodríguez-Castellón, Rinaldo S. Araujo, Monique S. Souza, and Rossano Lang. 2020. "Selective Catalytic Reduction of NO_x by CO over Doubly Promoted MeMo/Nb₂O₅ Catalysts (Me = Pt, Ni, or Co)" Catalysts 10, no. 9: 1048. https://doi.org/10.3390/catal10091048

APA Style

Nascimento, J. P. S., Oton, L. F., Oliveira, A. C., Rodríguez-Aguado, E., Rodríguez-Castellón, E., Araujo, R. S., Souza, M. S., & Lang, R. (2020). Selective Catalytic Reduction of NO_x by CO over Doubly Promoted MeMo/Nb₂O₅ Catalysts (Me = Pt, Ni, or Co). Catalysts, 10(9), 1048. https://doi.org/10.3390/catal10091048

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Selective Catalytic Reduction of NO_x by CO over Doubly Promoted MeMo/Nb₂O₅ Catalysts (Me = Pt, Ni, or Co)

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