High-entropy perovskites La M 0.2 Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 O 3−δ ( M = Cr, Ti) for ethanol steam reforming

Ethanol steam reforming is a promising route for hydrogen production from renewable sources, but catalyst deactivation caused by metal sintering and carbon deposition remains a major limitation. Hence, the search for novel stable catalysts is imperative. A promising approach is using the catalysts based on high-entropy perovskites, which possess high oxygen mobility and surface reactivity, as well as enhanced stability, which may contribute to the suppression of catalyst sintering and coke formation. In this study, the catalysts for ethanol steam reforming based on high-entropy perovskites La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3−δ (LCMFCN) and La(Ti0.2Mn0.2Fe0.2Co0.2Ni0.2)O3−δ (LTMFCN) were studied in comparison to the catalyst based on low-entropy perovskite LaMnO3−δ. The Ni-supported high-entropy perovskite catalysts showed improved ethanol steam reforming behavior compared with Ni/LaMnO3−δ, giving nearly complete ethanol conversion and H2/CO ratios above 3 at 700 °C. Among the studied catalysts, Ni/LCMFCN showed the strongest individual performance, reaching 99.84 % ethanol conversion, 54.99 % H2 yield, and H2/CO ratio of 3.38 at 700 °C. The 20 h stability test further showed that Ni/LCMFCN maintained nearly complete ethanol conversion with stable product selectivity. Post-reaction TEM analysis did not reveal massive carbon deposits blocking the catalyst surface. In the high-entropy perovskite-based catalysts, carbon was mainly observed in the form of filamentous carbon structures; no extensive surface-blocking coke layer was detected.