Hydration, CO2 stability and wireless electrochemical promotion studies on yttria-doped Ba (Ce, Zr) O3 perovskites

Abstract

BaCe 1 − x Y x O 3 − δ (BCY) and BaCe 0.8 − y Zr y Y 0.2 O 3 − δ (BCZY) perovskite mixed metal oxides were synthesised by an aqueous sol-gel technique to be investigated for their suitability in intermediate-temperature catalytic applications such as Electrochemical Promotion of Catalysis. The hydration capacity and the stability under CO 2 environments of the samples were studied using thermogravimetric analysis. Based on the evaluation of these properties, BaCe 0.6 Zr 0.2 Y 0.2 O 3 − δ (BCZ20Y20) was selected as the membrane support for wireless Electrochemical Promotion for CO oxidation on Pt. In a dual-chamber reactor, the use of H 2 /H 2 O flow in the sweep side induced promoting species supply to the catalyst in the reaction side of the reactor. Moderate promotion of the catalytic rate up to 10% was observed for temperatures up to 650°C, while this promotional effect was reversible and repeatable. The encouraging preliminary catalytic experiments together with the membrane's stability under the applied conditions reinforce the candidacy of BCZY membranes for intermediate-temperature applications in catalytic membrane reactors.

A Discussion on the Unique Features of Electrochemical Promotion of Catalysis (EPOC): Are We in the Right Path Towards Commercial Implementation?

“…The Vayenas group was the first to establish an equivalence between MSI and EPOC, in a way that traditional EPOC can be considered as an electrochemically controlled MSI [57]. Put differently, MSI can be considered as a type of "self-sustained electrochemical promotion" (SSEP) [12,[58][59][60][61] and also led to the so-called "wireless EPOC" in a double chamber reactor configuration [62,63]. This way, conventional catalytic reactors could be directly used for this MSI approach, as well as other kind of reactors based on perovskite-like hollow fiber membranes like the one developed by the Metcalfe group [64].…”