Multimetallic catalysts of RuO₂–CuO–Cs₂O–TiO₂/SiO₂for direct gas-phase epoxidation of propylene to propylene oxide

Abstract

RuO2–CuO–Cs2O–TiO2/SiO2 catalyst is highly active for the epoxidation of propylene to propylene oxide, producing 3015 gPO h−1 kgcat−1, the highest PO formation rate reported to date.

Synthesis of Light Hydrocarbons via Oxidative Coupling of Methane over Silica-supported Na2WO4-TiO2 Catalyst

“…11). For the TiO2/SiO2 catalyst, no clear H2 reduction peak could be seen in this temperature range, consistent with previous reports [21,22]. For Na2WO4/SiO2, a broad reduction peak starting from 450 ºC to above 900 ºC with a maximum H2 consumption at about 800 ºC was observed, indicating the reduction of W species [22].…”

Direct Z-Scheme Cs2O–Bi2O3–ZnO Heterostructures as Efficient Sunlight-Driven Photocatalysts

“…For pure Bi 2 O 3 , the Bi 4f 5/2 and Bi 4f 7/2 peaks are observed respectively at 163.9 and 158.6 eV, 52 whereas, in the present case, these peaks (Bi 4f 5/2 and Bi 4f 7/2 ) are found to be upward-shifted to 164.9 and 159.6 eV, respectively (Figure 2e). The reported XPS peaks of Cs 3d at 725.2 eV for Cs 3d 5/2 and at 739.2 eV for Cs 3d 3/2 53,54 are observed to be downward-shifted to respective positions of 724.4 and 738.5 eV in the Cs 2 O–Bi 2 O 3 –ZnO heterostructure (Figure 2d). In short, the upward shifts observed in the positions of Zn 2p 1/2 , Zn 2p 3/2 , Bi 4f 5/2 , and Bi 4f 7/2 , and the downward shifts observed in the positions of Cs 3d 3/2 and Cs 3d 5/2 confirm that the electrons migrate from the Bi 2 O 3 CB and ZnO CB to Cs 2 O CB (Scheme S1).…”

Chemical looping beyond combustion – a perspective

“…For a mixed MoO 3 /Bi 2 SiO 5 catalysts supported on SiO 2 , propylene oxide selectivities of 55% were reported at a propylene conversion of 22% at 400 1C for a diluted feed with a molar ratio of O 2 /C 3 H 6 of 4 : 1, 343 whereas high formation rates of propylene oxide were observed for a RuO 2 /CuO catalyst supported on SiO 2 . 344 Using a copper-manganese mixed metal oxide catalyst, Seubsai et al 345 found selectivities 430% towards propylene oxide at up to 1.5% propylene conversion at 300 1C. These catalyst systems are structurally and chemically similar to typical chemical looping redox catalysts, indicating the potential for future work in this field.…”