Yue L, Zhao W, Li J, Wu R, Wang Y, Zhang H, Zhao Y. Low-temperature CO preferential oxidation in H
2-rich stream over Indium modified Pd-Cu/Al
2O
3 catalyst.
J Colloid Interface Sci 2024;
662:109-118. [PMID:
38340510 DOI:
10.1016/j.jcis.2024.02.003]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/12/2024]
Abstract
The impact of Indium (In) doping upon the catalytic performance of Pd-Cu/Al2O3 for carbon monoxide preferential oxidation (CO-PROX) in hydrogen (H2) rich atmosphere at low temperature has been studied. A series of catalysts with extremely low palladium (Pd) loading (0.06 wt%) are synthesized by the facile co-impregnation method. When the In/copper (Cu) atomic ratio equals 0.25, Pd-Cu-In0.25/Al2O3 can keep 40% CO conversion and 100% carbon dioxide (CO2) selectivity at least 120 min at 30 °C, which is significantly superior to the catalytic performance of Pd-Cu/Al2O3. The elaborate characterization findings reveal that the added In species to Pd-Cu/Al2O3 causes Indium oxide (In2O3) to generate, which produces the interaction of In2O3 with Pd-Cu/Al2O3, further promoting the dispersion of copper chloride hydroxide (Cu2Cl(OH)3). Moreover, the modification of In facilitates the re-oxidation of Pd0 to Pd+ through reducing the formation of palladium hydride (PdHx) during the CO-PROX reaction. Meanwhile, the addition of In leads to the decrease of Cu+ electron cloud density, making it easier to be oxidized to Cu2+. Collectively, the easy re-oxidation of Pd0 and Cu+ is favorable to fulfill the Wacker cycle between Pd and Cu species, thus improving the catalytic performance for CO-PROX.
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