Hydrodechlorination and deep hydrogenation on single-palladium-atom-based heterogeneous catalysts

• Published in: Applied catalysis. B, Environmental Environmental, 2021-03, Vol.282, p.119518, Article 119518
• Main Authors: Li, Jiacheng, Li, Miao, Li, Jing, Wang, Sai, Li, Gongbo, Liu, Xiang
• Format: Article
• Language: English
• Subjects: 4-Chlorophenol; Catalysis; Catalysts; Cerium oxides; Density functional theory; Groundwater; Hydrodechlorination; Intermediates; Palladium; PdCatalysis; Reaction mechanisms; Single atom; Single atom catalysts; Wastewater; Water
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.119518

Illustration for the 4-CP catalytic HDC reaction on Pd SACs. [Display omitted] •Pd-based SACs with superior performance were prepared and used in the catalytic HDC for the first time.•The coordination environments of Pd atoms were mediated by different kinds of defect-rich supports.•The MIMSI effect was identified as a critical factor of the highest catalytic performance of Pd/CeO2 SACs.•Density functional theory calculations were performed to obtain a fundamental understanding of the HDC mechanism. Halophenols are widely present in wastewater and groundwater, which threaten global water safety and human health. Importantly, hydrodechlorination (HDC) via heterogeneous catalysis is efficient and environmentally friendly. To further improve the catalytic performance and atomic economy, Pd-based single atom catalysts (SACs) were prepared through electrostatic attraction and used in the catalytic HDC for the first time. By substituting different defect-rich supports, the coordination environments of atomically dispersed Pd-atoms were mediated with different catalytic performance. The results demonstrate that the Pd/CeO2 SACs have the highest HDC activity and remain stable during cycle tests. The moderately intensive metal-support interactions (MIMSI) effect was identified as a critical factor for the higher activity of SACs, unlike the traditional strong metal-support interaction effect. The HDC process on Pd SACs was further investigated by combining kinetic experiments with density functional theory calculations, which facilitated the recognition of HDC intermediates and an understanding of the reaction mechanism.