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1,636 results on '"Zheng, Shu"'

10. Properties of the FCC Catalyst Additive Prepared from Guizhou Kaoline

Author

Xianlun Xu, Zheng-Guo Tan, Zhang, Yu-Li, Ding, Wei, and Zheng, Shu-Qin

Subjects
kaoline, in situ crystalliazation technique, catalytic cracking, FCC additive, heavy metal, zeolite, Chemistry, QD1-999
Abstract

The properties of a FCC catalyst additive prepared from Guizhou kaoline were extensively investigated. The samples were characterized by N2 adsorption, X-ray diffraction, IR spectrometry, and scanning electron microscope (SEM). The results showed that the crystallinity of NaY zeolite synthesized from this kaoline was 25% and the silica alumina ratio was rk/s ˇ m = 5.05. The catalyst additive prepared from above crystallization product exhibited excellent performance of nickel and vanadium passivation, offered 21% lower coke versus base catalyst, while maintaining high bottoms upgrading selectivity.

Published
2006

11. Fundamentally Manipulating the Electronic Structure of Polar Bifunctional Catalysts for Lithium‐Sulfur Batteries: Heterojunction Design versus Doping Engineering

Author

Huifang Xu, Qingbin Jiang, Zheng Shu, Kwan San Hui, Shuo Wang, Yunshan Zheng, Xiaolu Liu, Huixian Xie, Weng‐Fai (Andy) Ip, Chenyang Zha, Yongqing Cai, and Kwun Nam Hui

Subjects
active sites, doping strategies, electronic structures, heterogeneous structures, polar catalysts, Science
Abstract

Abstract Heterogeneous structures and doping strategies have been intensively used to manipulate the catalytic conversion of polysulfides to enhance reaction kinetics and suppress the shuttle effect in lithium‐sulfur (Li‐S) batteries. However, understanding how to select suitable strategies for engineering the electronic structure of polar catalysts is lacking. Here, a comparative investigation between heterogeneous structures and doping strategies is conducted to assess their impact on the modulation of the electronic structures and their effectiveness in catalyzing the conversion of polysulfides. These findings reveal that Co0.125Zn0.875Se, with metal‐cation dopants, exhibits superior performance compared to CoSe2/ZnSe heterogeneous structures. The incorporation of low Co2+ dopants induces the subtle lattice strain in Co0.125Zn0.875Se, resulting in the increased exposure of active sites. As a result, Co0.125Zn0.875Se demonstrates enhanced electron accumulation on surface Se sites, improved charge carrier mobility, and optimized both p‐band and d‐band centers. The Li‐S cells employing Co0.125Zn0.875Se catalyst demonstrate significantly improved capacity (1261.3 mAh g−1 at 0.5 C) and cycle stability (0.048% capacity delay rate within 1000 cycles at 2 C). This study provides valuable guidance for the modulation of the electronic structure of typical polar catalysts, serving as a design directive to tailor the catalytic activity of advanced Li‐S catalysts.

Published
2024
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35. Directly imaging excited state-resolved transient structures of water induced by valence and inner-shell ionisation

Author

Zhenzhen Wang, Xiaoqing Hu, Xiaorui Xue, Shengpeng Zhou, Xiaokai Li, Yizhang Yang, Jiaqi Zhou, Zheng Shu, Banchi Zhao, Xitao Yu, Maomao Gong, Zhenpeng Wang, Pan Ma, Yong Wu, Xiangjun Chen, Jianguo Wang, Xueguang Ren, Chuncheng Wang, and Dajun Ding

Subjects
Science
Abstract

Abstract Real-time imaging of transient structure of the electronic excited state is fundamentally critical to understand and control ultrafast molecular dynamics. The ejection of electrons from the inner-shell and valence level can lead to the population of different excited states, which trigger manifold ultrafast relaxation processes, however, the accurate imaging of such electronic state-dependent structural evolutions is still lacking. Here, by developing the laser-induced electron recollision-assisted Coulomb explosion imaging approach and molecular dynamics simulations, snapshots of the vibrational wave-packets of the excited (A) and ground states (X) of D2O+ are captured simultaneously with sub-10 picometre and few-femtosecond precision. We visualise that θ DOD and ROD are significantly increased by around 50∘ and 10 pm, respectively, within approximately 8 fs after initial ionisation for the A state, and the ROD further extends 9 pm within 2 fs along the ground state of the dication in the present condition. Moreover, the ROD can stretch more than 50 pm within 5 fs along autoionisation state of dication. The accuracies of the results are limited by the simulations. These results provide comprehensive structural information for studying the fascinating molecular dynamics of water, and pave the way towards to make a movie of excited state-resolved ultrafast molecular dynamics and light-induced chemical reaction.

Published
2023
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