Support-rebalanced Cu-Ce-V/γ-Al₂O₃ catalysts for durable fixed-bed HCl oxidation: Redox-acid-oxygen rebalancing for...

Catalytic oxidation of waste HCl to Cl₂ enables chlorine recycling, but its practical implementation requires shaped catalysts that combine high productivity with long-term chemical and mechanical stability. Herein, a spherical Cu-Ce-V/γ-Al₂O₃ catalyst was developed by integrating a redox-active Cu-Ce-V oxide ensemble with mechanically robust γ-Al₂O₃ pellets for fixed-bed HCl oxidation. At a catalyst-bed temperature of 420 ± 5 °C under an undiluted HCl/O₂ feed, the catalyst achieved an HCl conversion of approximately 78.2% and a Cl₂ space-time yield of 17.04 mol∙kg_act^-1∙h^-1. Stable fixed-bed operation was maintained for 200 h, accompanied by 98.41% mass retention after ultrasonication, 97.8% Cu retention, and 81.6% surface-area retention. Post-reaction characterization revealed that γ-Al₂O₃ induces a redox-acid-oxygen rebalancing of the Cu-Ce-V phase, generating a more oxidized and moderately reducible cationic state while retaining oxygen-release capacity and a Lewis-acid-dominated environment for HCl adsorption. In situ DRIFTS further shows that HCl induces the accumulation of hydroxylated and hydrated surface species, whereas O₂ co-feeding markedly attenuates these surface descriptors. Therefore, these results suggest that the alumina-supported architecture dynamically moderates HCl-induced surface evolution and suppresses irreversible structural degradation. This work provides a thermodynamically consistent strategy for translating Cu-Ce-V redox chemistry into a durable shaped catalyst for fixed-bed HCl-to-Cl₂ recycling.