Oxidation of thiophene over copper-manganese mixed oxides

Abstract

Commercial hopcalite calcined at different temperatures and hopcalite modified with noble metals (Pt, Pd, and Au) were studied in oxidation of thiophene. Surface and bulk properties of catalysts were studied using temperature-programmed reduction (TPRH2), X-ray diffraction method (XRD) and thermal analysis (TG-DTA-MS). It was shown that calcined samples displayed higher activity in comparison with commercial untreated hopcalite; however, a lower temperature of calcination was favourable. High temperature of thermal treatment induced an increase in the crystallinity and a decrease in the surface area of the samples, and, as a consequence, the loss of catalysts activity. Moreover, marked improvement in the catalytic performance of platinum and palladium modified catalysts in relation to base hopcalite was observed. The obtained results indicate that the higher activity of samples containing Pt and Pd was accompanied by better reducibility of the catalysts.

The Influence of Thermal Treatment and Noble Metal Addition on Hopcalite Activity in Oxidation of Thiophene

“…Our previous studies showed that commercial hopcalite calcined at different temperatures (300, 400, 500°C) displayed a higher activity in oxidation of thiophene in comparison with commercial untreated hopcalite [37]. Catalyst calcined at 300°C characterized by amorphous structure, the highest surface area and the best reducibility indicated the most promising performance among studied samples, however, a decrease of its activity above amorphous to crystalline phase transition was observed under reaction conditions applied.…”

“…Moreover, the beneficial effect of an addition of Pd, Pt and Au was also observed, nevertheless noble metals doped hopcalite catalyst calcined at 400 and 500°C exhibited similar catalytic behaviour independently of calcination temperature [37][38][39]. It was also shown that commercial hopcalite modified with Pd demonstrated the highest activity among studied samples [39]. A higher activity of hopcalite containing Pd can be accompanied by better reducibility of the catalysts comparing to hopcalite modified with Pt or Au [37].…”

“…Catalyst calcined at 300°C characterized by amorphous structure, the highest surface area and the best reducibility indicated the most promising performance among studied samples, however, a decrease of its activity above amorphous to crystalline phase transition was observed under reaction conditions applied. Moreover, the beneficial effect of an addition of Pd, Pt and Au was also observed, nevertheless noble metals doped hopcalite catalyst calcined at 400 and 500°C exhibited similar catalytic behaviour independently of calcination temperature [37][38][39]. It was also shown that commercial hopcalite modified with Pd demonstrated the highest activity among studied samples [39].…”

“…It was also shown that commercial hopcalite modified with Pd demonstrated the highest activity among studied samples [39]. A higher activity of hopcalite containing Pd can be accompanied by better reducibility of the catalysts comparing to hopcalite modified with Pt or Au [37]. On the other hand, nonhomogenous distribution of Au atoms observed on the catalyst surface could have an influence on the lowest oxidation activity of Au modified systems.…”

Analysis of the application of selected physico-chemical methods in eliminating odor nuisance of municipal facilities

“…Depending on the type and amount of pollutants, the oxidation process is carried out directly in flame or thermally. The efficiency of the thermal combustion is high, almost 100% [8]. During catalytic oxidation, the oxidation of gases takes place on the surface of the catalyst.…”