Effect of thermal treatment on the stability of Na–Mn–W/SiO₂ catalyst for the oxidative coupling of methane

Abstract

In this study, we investigate the effect of thermal treatment/calcination on the stability and activity of a Na-Mn-W/SiO2 catalyst for the oxidative coupling of methane reaction. The catalyst performance and...

In situ X-ray diffraction computed tomography studies examining the thermal and chemical stabilities of working Ba0.5Sr0.5Co0.8Fe0.2O3−δ membranes during oxidative coupling of methane

“…The behavior of the W species results from the intrinsic instability of Na-Mn-W/SiO 2 catalyst at high temperatures and under operating conditions; this problem could potentially be solved through the chemical promotion and/or thermal treatment. 51,52 Fig. 11 Elemental distribution at the inner side of membrane obtained by EDX mapping.…”

“…Regarding the solid-state chemistry of the other catalyst components, the temperature induced a gradual transition between cristobalite and tridymite during the OCM reaction. 51,52 In addition, the Mn 2 O 3 phase was seen to disappear after the introduction of the OCM reaction mixture. However, it temporarily reappeared after the introduction of the reaction mixture containing pure CO 2 (possibly due to the CO 2 reduction by Mn 2+ /Mn 3+ ).…”

Multi-Scale Studies of 3D Printed Mn–Na–W/SiO2 Catalyst for Oxidative Coupling of Methane

“…al. [39] for this catalyst, a longer calcination period leads to a better stability of the catalyst, resulting in a more constant performance over a longer period of time. However, there is a trade-off since the calcination leads to a reduction of the catalyst's specific surface area.…”

“…Synchrotron based X-ray diffraction computed tomography (XRD-CT) technique has been previously used to investigate catalyst systems under reaction conditions [32][33][34][35]. Matras et al and Vamvakeros et al [8,[36][37][38][39][40] have performed real-time tomographic diffraction imaging of catalytic membrane reactors (CMRs) under OCM reaction conditions over Mn-Na-W/SiO 2 catalysts packed inside Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCF) [8] and BaCo x Fe y Zr z O 3−δ (BCFZ) hollow fiber oxygen membranes [36,38] respectively.…”

Multi-length scale 5D diffraction imaging of Ni–Pd/CeO2–ZrO2/Al2O3 catalyst during partial oxidation of methane

“…X-ray diffraction computed tomography (XRD-CT) is a powerful characterisation technique which has been lately applied to study a variety of functional materials and devices including operating solid catalysts, fuel cells and batteries. [53][54][55][56][57][58][59][60][61][62][63][64] The radial distribution of the various crystalline catalyst components under operating conditions was investigated with the 3D-XRD-CT technique. In addition, the fast solidstate changes occurring along the catalyst bed were followed with X-ray diffraction mapping.…”