Hualei Hu,Jinghui Lyu,Jie Cen,Qunfeng Zhang,Qingtao Wang,Wenwen Han,Jiayao Rui,Xiaonian Li
The effect of MgO and Pd modification on the catalytic performance of hierarchical porous ZSM-5 for benzene alkylation with methanol was investigated. The results indicated that the introduction of MgO could reduce the Brönsted acid sites which suppressed the side reaction of methanol to olefins and in turn effectively promoted the alkylation of benzene. However, the single modification of MgO could not completely suppress the formation of ethylbenzene and coke. Doping a small amount of Pd had a positive effect on inhibiting the generation of ethylbenzene and coke, which could be attributed to the hydrogenation of ethylene into ethane on Pd. The dual modified catalyst (MgO and Pd) exhibited high benzene conversion (56%) and xylene selectivity (39.1%), and the lowest ethylbenzene selectivity (0.13%) and coke content (0.4 wt%).
Jianxin Lv,Linghui Zhang,Lianxi Si,Hui Li,Wenbo Zhao,Fei An,Xia Feng,Shi Hu
Materials with accurate and durable gas detection are essential for gas sensors. We developed a facile and effective method to deposit Pd onto WO3 nanosheets and used the samples for hydrogen gas sensing. The combination of the 2D ultrathin nanostructure of WO3 and the spillover effect of Pd enables a detection concentration down to 20 ppm of hydrogen and high selectivity against other gases including methane, butane, acetone, isopropanol, etc. Moreover, the durability of the sensing materials was testified through 50 cycles of exposure to 200 ppm of hydrogen. These outstanding performances are mainly attributed to a homogeneous and tenacious decoration of Pd on the surface of WO3 nanosheets, providing an attractive choice for practical applications.
Ziyu Xie,Jing Chen,Yanxin Chen,Tianming Wang,Xia Jiang,Yiming Xie,Can-Zhong Lu
Pd modified ZnIn 2 S 4 /P25 (Pd@ZnIn 2 S 4 /P25) heterostructures have been synthesized by hydrothermal and photo-reduction method. The H 2 evolution rate of optimal photocatalyst 0.5 %Pd modified 5ZnIn 2 S 4 /2P25 (0.5 %Pd@5ZnIn 2 S 4 /2P25) are approximately 9100 and 3693 μmol · g −1 h −1 under simulated sunlight and visible light irradiation with ethanol as the sacrificial agent, which are nearly 9 and 460 times higher than pure ZnIn 2 S 4 and P25, respectively. The promoted photocatalytic performance can be attributed to the physicochemical properties of the catalysts and the strong electronic interaction between Pd modified ZnIn 2 S 4 (Pd@ZnIn 2 S 4 ) and P25, the improved transfer rate of photo-generated electrons and holes, the inhibited recombination of charge carriers, and the enhanced light harvesting. The results of photo-electrochemistry and EPR indicate that it is a Z-scheme photocatalytic system, in which the electrons accumulate on the conduct band of ZnIn 2 S 4 and the holes assemble on the valence band of P25. This work provides an effective method to construct highly efficient photocatalytic systems for solar H 2 generation.
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