Fe Speciation in Iron Modified Natural Zeolites as Sustainable Environmental Catalysts

Catalysts

Daria Tito Ferro¹  Vitalii Petranovskii²  Gloria Berlier³  Fernando Chávez Rivas⁴  Inocente Rodríguez-Iznaga⁵  Beatriz Concepción-Rosabal⁵ 

[1] Centro Nacional de Electromagnetismo Aplicado (CNEA), Universidad de Oriente, Ave. Las Américas s/n, Santiago de Cuba, C.P. 90400, Cuba;Departamento de Nanocatálisis, Centro de Nanociencias y Nanotecnología (CNyN), Universidad Nacional Autónoma de México, Carretera Tijuana-Ensenada, Km 107. Ensenada, C.P. 22860 BC, Mexico;Dipartimento di Chimica and NIS Centre, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy;Instituto Politécnico Nacional, ESFM, Departamento de Física, UPALM, Zacatenco, Ciudad de México 07738, Mexico;Instituto de Ciencia y Tecnología de Materiales (IMRE)-Universidad de La Habana, Zapata y G s/n, La Habana, C.P. 10400, Cuba;

关键词: natural zeolite;    mordenite;    iron exchange;    ftir-no;    hrtem;    no reduction;   

DOI  :  10.3390/catal9100866

来源: DOAJ

【 摘 要 】

Natural purified mordenite from Palmarito de Cauto (ZP) deposit, Cuba, was subjected to a hydrothermal ion exchange process in acid medium with Fe²⁺ or Fe³⁺ salts (Fe²⁺ZP and Fe³⁺ZP). The set of samples was characterized regarding their textural properties, morphology, and crystallinity, and tested in the NO reduction with CO/C₃H₆. Infrared spectroscopy coupled with NO as a probe molecule was used to give a qualitative description of the Fe species’ nature and distribution. The exchange process caused an increase in the iron loading of the samples and a redistribution, resulting in more dispersed Fe²⁺ and Fe³⁺ species. When contacted with the NO probe, Fe²⁺ZP showed the highest intensity of nitrosyl bands, assigned to NO adducts on isolated/highly dispersed Fe²⁺/Fe³⁺ extra-framework sites and Fe_xO_y clusters. This sample is also characterized by the highest NO sorption capacity and activity in NO reduction. Fe³⁺ZP showed a higher intensity of nitrosonium (NO⁺) species, without a correlation to NO storage and conversion, pointing to the reactivity of small Fe_xO_y aggregates in providing oxygen atoms for the NO to NO⁺ reaction. The same sites are proposed to be responsible for the higher production of CO₂ observed on this sample, and thus to be detrimental to the activity in NO SCR.

【 授权许可】

Unknown