Insight into methanol photooxidation over mono- (Au, Cu) and bimetallic (AuCu) catalysts supported on niobium pentoxide — An operando-IR study - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Applied Catalysis B: Environmental Année : 2019

Insight into methanol photooxidation over mono- (Au, Cu) and bimetallic (AuCu) catalysts supported on niobium pentoxide — An operando-IR study

Résumé

The aim of this study was to gain deeper insight into the factors determining the activity and selectivity of mono- (Au, Cu) and bimetallic (AuCu) catalysts supported on niobium pentoxide in photocatalytic oxidation of methanol. For this purpose, the prepared catalysts were comprehensively characterized with the use of XRD, nitrogen sorption, ICP-OES, UV-Vis, XPS, TEM and FTIR spectroscopy combined with in situ adsorption of probe molecules (methanol and pyridine). Photocatalytic activity of the materials was evaluated with the use of operando-IR system under irradiation with different light sources, i.e. UV and visible light. It was demonstrated that under UV irradiation, gold and/or copper dopants reduced the niobia activity but enhanced the reaction selectivity. Under visible light irradiation, the decoration of the niobia with bimetallic nanoparticles of gold and copper led to a synergic enhancement of the photocatalyst performance relative that of monometallic and non-doped niobia photocatalysts, tested under the same reaction conditions. It was also demonstrated that the selectivity over the bimetallic gold-copper/Nb2O5 catalyst was strongly affected by the nature of the light source: visible light irradiation promoted a total oxidation versus a partial oxidation of methanol under UV light irradiation. The relationship between the properties of the catalysts and their activity/selectivity considered in this work allowed explanation of differences in the photocatalysts behavior. It also permitted estimation of the role of individual catalyst components in the photocatalytic process. Moreover, monitoring of methanol photooxidation with the use of operando-IR system enabled estimation of reaction pathways and mechanism.
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Dates et versions

hal-02355038 , version 1 (25-11-2020)

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L. Wolski, M. El-Roz, M. Daturi, G. Nowaczyk, M. Ziolek. Insight into methanol photooxidation over mono- (Au, Cu) and bimetallic (AuCu) catalysts supported on niobium pentoxide — An operando-IR study. Applied Catalysis B: Environmental, 2019, 258, pp.117978. ⟨10.1016/j.apcatb.2019.117978⟩. ⟨hal-02355038⟩
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