Oxidation of ethylene by Cu/TiO2: reducibility of Cu2+ in TiO2 as a possible descriptor of catalytic efficiency. Issue 8 (30th March 2023)

• Record Type: Journal Article
• Authors: Rajendran, K.; Sharma, Mandeep; Jaison, Augustine; Ankitha, Menon; Tiwari, Ankit D.; Vinod, C. P.; Jagadeesan, Dinesh
• Is Part Of: Catalysis science & technology. Volume 13:Issue 8(2023)
• Page Start: 2330
• Page End: 2339
• Publication Date: 2023-03-30
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/d2cy02170f
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : Catalytic oxidation using non-noble metal-based catalysts is a promising approach to mitigate pollution due to VOCs in the air. Abstract : Catalytic oxidation using non-noble metal-based catalysts is a promising approach to mitigate pollution due to VOCs in the air. In this work, mesoporous Cu/TiO2 catalysts containing different concentrations of Cu 2+ (0.2, 1, 3, and 4 wt% Cu w.r.t. Ti) were synthesized using the sol–gel technique. The catalysts were characterized using inductively coupled plasma-optical emission spectrometry, XRD, Raman spectroscopy, N2 physisorption, cyclic voltammetry, H2 -TPR and electron microscopy to understand the structure and composition. The thermal catalytic gas phase oxidation of ethylene was studied by heating a mixture of ethylene (1.5 vol%) and air (5.9 vol%) in the presence of the Cu/TiO2 samples in the temperature range of 298 to 773 K. Cu/TiO2 showed a higher catalytic activity compared to TiO2 for the thermal oxidation of ethylene, indicating a strong promotion by doped copper ions. A volcanic behaviour in the catalytic activity was observed with different concentrations of Cu doping, with 1% Cu/TiO2 showing a 99.5% ethylene conversion at 673 K and 100% selectivity to CO2 . The activity of 1% Cu/TiO2 remained consistent without deactivation for 24 h. At low dopant concentrations of Cu (0.2 and 1% Cu/TiO2 ), the reduction of Cu 2+ to Cu + was observed. An interplay of oxygen vacancies (OV ), Cu +, Cu 2+ and Ti 4+ may be involved in controlling the activity. DRIFT studies indicated the formation of surface bidendate carbonate as a possible intermediate.