Light-Induced Selective Hydrogenation over PdAg Nanocages in Hollow MOF Microenvironment
Luyan Li, Yanxiao Li, Long Jiao, Xiaoshuo Liu, Zhentao Ma, Y. J. Zeng, Xusheng Zheng, Hai‐Long Jiang
Abstract
Selective hydrogenation with high efficiency under ambient conditions remains a long-standing challenge. Here, a yolk–shell nanostructured catalyst, PdAg@ZIF-8, featuring plasmonic PdAg nanocages encompassed by a metal–organic framework (MOF, namely, ZIF-8) shell, has been rationally fabricated. PdAg@ZIF-8 achieves selective (97.5%) hydrogenation of nitrostyrene to vinylaniline with complete conversion at ambient temperature under visible light irradiation. The photothermal effect of Ag, together with the substrate enrichment effect of the catalyst, improves the Pd activity. The near-field enhancement effect from plasmonic Ag and optimized Pd electronic state by Ag alloying promote selective adsorption of the −NO2 group and therefore catalytic selectivity. Remarkably, the unique yolk–shell nanostructure not only facilitates access to PdAg cores and protects them from aggregation but also benefits substrate enrichment and preferential −NO2 adsorption under light irradiation, the latter two of which surpass the core–shell counterpart, giving rise to enhanced activity, selectivity, and recyclability.