Catalytic hydrodechlorination of chlorophenols over facet-specific Pd nanocrystals

Abstract

Clarifying the reaction mechanism of catalytic hydrodechlorination (HDC) and designing Pd surface structures with high catalytic activity are crucial for maximizing its ability to remove chlorophenol pollutants. In this study, single-crystalline Pd nanocrystals enclosed by {110}, {100} or {111} facets with average particle diameters ∼ 6.5 nm were prepared and then originally evaluated their activities for catalytic HDC of chlorophenols. The experimental results indicate that dodecahedral Pd nanocrystals enclosed with {110} facets show the highest catalytic activity for HDC of chlorophenols with a turnover frequency up to 19.1 min−1, which is ∼ 3.1 times as high as that of cubic Pd nanocrystals and 12.7 times higher than that of octahedral Pd nanocrystals. Theoretic calculations reveal that Pd (110) facets have the strongest activation ability for chlorophenol and the lower energy barrier in dechlorination and hydrogenation steps. Moreover, dodecahedral Pd nanocrystals exhibit high HDC activity for various chlorophenolic derivatives and structural stability. We believe that the study could provide insights into the understanding and design of highly efficient Pd systems for various HDC reactions.