Novel nano-semiconductor film layer supported nano-Pd Complex Nanostructured Catalyst Pd/Ⓕ-MeOx/AC for High Efficient Selective Hydrogenation of Phenol to Cyclohexanone
Supported metal as a type of heterogeneous catalysts are the most widely used in industrial processes. High dispersion of the metal particles of supported catalyst is a key factor in determining the performance of such catalysts. Here we report a novel catalyst Pd/Ⓕ-MeOx/AC with complex nanostructured, Pd nanoparticles supported on the platelike nano-semiconductor film/activated carbon, prepared by the photocatalytic reduction method, which exhibited high efficient catalytic performance for selective hydrogenation of phenol to cyclohexanone. Conversion of phenol achieved up to more than 99% with a lower mole ratio (0.5%) of active components Pd and phenol within 2 h at 70 °C. The synergistic effect of metal nanoparticles and nano-semiconductors support layer and the greatly increasing of contact interface of nano-metal-semiconductors may be responsible for the high efficiency. This work provides a clear demonstration that complex nanostructured catalysts with nano-metal and nano-semiconductor film layer supported on high specific surface AC can yield enhanced catalytic activity and can afford promising approach for developing new supported catalyst.
Synergistic catalytic hydrogenation of phenol over hybrid nano-structure Pd catalyst
Abstract Pd-based catalyst is one of the most widely used catalysts in the selective hydrogenation of phenol. Herein, a new strategy has been developed to fabricate a hybrid nano-structure Pd catalyst. By coating ZrO2 on the activated carbon(AC), then anchored Pd nanoparticles on the ZrO2/AC, a hybrid nano-structure Pd/@-ZrO2/AC catalyst with strong synergy can be obtained. The results show that the Pd/@-ZrO2/AC catalyst exhibited a synergistic effect and remarkable catalytic activity in the selective hydrogenation of phenol, outperforming both conventional Pd/ZrO2 and Pd/AC catalyst. Importantly, the catalytic activity was closely related to the calcination temperature of ZrO2/AC. The ZrO2/AC support was calcined at 500℃ with a minimum particle size, which enables Pd nanoparticles to support on it with high dispersion. Then the Pd/@-ZrO2/AC(500) exhibited stronger interaction of Pd nanoparticles with the ZrO2/AC surface as compared to other catalysts and shown the highest catalytic activity. Moreover, a series of this hybrid nano-structure Pd/@-MexOy/AC catalysts(MexOy: TiO2, CeO2, La2O3) have been synthesized and further confirmed the synergistic effect in the selective hydrogenation.
Nuclear sphingolipid metabolism.
Nuclear lipid metabolism is implicated in various processes, including transcription, splicing, and DNA repair. Sphingolipids play roles in numerous cellular functions, and an emerging body of literature has identified roles for these lipid mediators in distinct nuclear processes. Different sphingolipid species are localized in various subnuclear domains, including chromatin, the nuclear matrix, and the nuclear envelope, where sphingolipids exert specific regulatory and structural functions. Sphingomyelin, the most abundant nuclear sphingolipid, plays both structural and regulatory roles in chromatin assembly and dynamics in addition to being an integral component of the nuclear matrix. Sphingosine-1-phosphate modulates histone acetylation, sphingosine is a ligand for steroidogenic factor 1, and nuclear accumulation of ceramide has been implicated in apoptosis. Finally, nuclear membrane-associated ganglioside GM1 plays a pivotal role in Ca(2+) homeostasis. This review highlights research on the factors that control nuclear sphingolipid metabolism and summarizes the roles of these lipids in various nuclear processes.