Methane oxidation over Pt, Pt:Pd, and Pd based catalysts: Effects of pre‐treatment

Abstract

This paper presents a comparison of the activity for methane oxidation of selected commercial platinum, palladium, and platinum‐palladium supported catalysts. Precious metal loadings are typical of those found in the catalytic converters for lean‐burn natural gas engines. Experiments are presented for de‐greened as well as hydrothermally aged catalysts, both in the presence and the absence of water. For the platinum catalyst, fraction conversion of methane is shown to be independent of methane concentration, while for the palladium‐containing catalysts a dependence of conversion on methane partial pressure is observed. For catalysts containing palladium, reduction in hydrogen gives an increase in methane conversion activity, although the increase is subsequently lost in the oxidizing atmosphere. Hydrothermal aging of the platinum catalyst causes a relatively large and permanent loss in methane oxidation activity, while the palladium‐based catalysts showed more resistance to deactivation. Adding a small amount of palladium to the platinum catalyst provides an overall improvement in performance.

Selective oxidation of o‐chlorotoluene to o‐chlorobenzaldehyde catalyzed by (Co,Mn)(Co,Mn)2O4 catalysts

“…The average particle sizes obtained from the TEM images of the CM‐300, CM‐400, CM‐500, CM‐600, and CM‐700 samples are 10.8 nm, 18.5 nm, 20.8 nm, 38.7 nm, and 51.9 nm, respectively. These differences in particle size and crystallinity apparently will affect the activity and selectivity of the catalysts …”

Partial oxidation of methane to syngas over Pt/Rh/MgO catalyst supported on FeCralloy woven fibre

“…We cut three circular disks of the FeCralloy woven metal so that they fit snugly inside the tube. The total mass of the three disks was 0.27 g and we placed them 150 mm above the entrance without a reduction pretreatment . An electrical furnace heated the reactor to 900 °C.…”

The Impact of CeO2 Loading on the Activity and Stability of PdO/γ-AlOOH/γ-Al2O3 Monolith Catalysts for CH4 Oxidation

“…Natural gas is considered to be a suitable alternative fuel because combustion of natural gas produces less greenhouse gas (GHG) emissions per unit of energy than gasoline or diesel. The lower emissions are due to the high hydrogen-to-carbon ratio of the main component of natural gas, CH 4 [1]. Use of natural gas as a vehicle fuel is growing at about 21% per year worldwide.…”

“…Use of natural gas as a vehicle fuel is growing at about 21% per year worldwide. However, unburned CH 4 emitted in the exhaust gas of natural gas vehicles (NGVs), limit their growth [2,3] and several studies have focused on improving the efficiency of the NGV catalytic convertor so as to reduce CH 4 emissions to an acceptable level [1,[4][5][6][7][8][9][10][11]. Oxidation of CH 4 from NGV emissions is difficult because of the low concentrations of CH 4 (400-1500 ppm), the low exhaust gas temperatures (150-550 • C) from lean-burn NGVs [2,10] and the presence of high concentrations of H 2 O (5-15 vol.%) and CO 2 (10 vol.%) [3].…”