Oriented ZSM-5 Nanoarray Encapsulation Enabled Robust Monolithic Catalysts for CH₄ and CO₂ Conversion

Stable and active catalysts are the key to catalytic reactions requiring harsh conditions with high temperatures (&gt;600 °C) and moist content. However, it is challenging to maintain high activity when catalyst design strategies such as strong metal support interaction and physical encapsulation, are applied to improve stability due to a tradeoff in the reactivity sacrifice as a result^1–3. Through rational design and manipulation^4,5, we have demonstrated a well-defined nanoarray hybrid monolithic catalyst which is composed of transitional metal oxide (Co₃O₄) nanoarray and the encapsulation layer of brush-like oriented ZSM-5 nanoarray, denoted as CC-HZA. The hybrid nanoarray catalysts have shown high thermal stability and excellent activity for catalytic processes under harsh conditions. CC-HZA demonstrates superior thermal stability and catalyst activity for high-temperature reactions such as methane oxidation, reverse water gas shift, and methane dry reforming reaction under both oxidative and reductive conditions at a high-temperature range (600-700 °C, 1 bar) with moist conditions. The internal and external ZSM-5 confinement is revealed for the Co₃O₄ nanoarray forest, playing a key role in the demonstrated superior stability. Besides the encapsulation effect, the oriented ZSM-5 nanoarray offers important merits including (1) improved CO selectivity for RWGS, (2) strong hydrophilicity of ZSM-5, endowing the excellent catalyst water resistance, and (3) oriented hierarchical nanoarray structure, offering fast transfer with high activity and less material usage. This work provides a new design of highly thermal stable monolithic catalysts, which allows highly stabilized non-noble nanometal and metal oxides catalysts for high-temperature applications.<br/><b>Referenc</b><b>es</b><br/><b>1</b> Chaudhary, P. K. <i>et al.</i> <i>Colloids Surf A Physicochem Eng Asp</i> 646, 128973 (2022)<br/><b>2</b> Lou, Y. <i>et al.</i> <i>J Catal</i> 356, 147–156 (2017)<br/><b>3</b> Feng, X. <i>et al.</i> <i>Journal of Energy Chemistry</i> 75, 173–215 (2022)<br/><b>4</b> Lu, X. <i>et al.</i> <i>Catal Today</i> 360, 275–283 (2021)<br/><b>5</b> Du, S. <i>et al.</i> <i>Appl Catal B</i> 236, 348–358 (2018)