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280 results on '"Zhao, Xinhong"'

23. Methylation of Toluene with Methanol over Ru@HZSM-5: An Investigation into Profoundly Altering Side Reactions While Preserving the Main Reaction Pathway through Density Functional Theory

Author

Dong, Peng, Zhang, Xiaohui, Shao, Tingna, Li, Jinlian, Wang, Xiaorui, Zhao, Yu, Zhao, Xinhong, and Li, Guixian

Abstract

The emphasis in the field of the methylation of toluene with methanol to produce paraxylene (PX) has focused primarily on the development of highly active and shape-selective catalysts. In contrast, there has been a limited focus on the technology for eliminating byproduct olefins in reaction systems. The removal of olefins is a crucial factor in prolonging the lifespan of the catalyst, as the competitive methanol-to-hydrocarbon (MTH) reaction is prone to occur in this reaction system, leading to increased coke deposition and subsequent catalyst deactivation. Considering the high selectivity and strong coke resistance exhibited by Ru@HZSM-5, we utilize density functional theory (DFT) calculations to explore the first C–C bond formation through the oxonium ion mechanism as well as the methylation pathway of methanol in the process of methylating toluene with methanol to produce PX. The results show that the addition of Ru not only changes the byproduct reaction pathway without affecting the main reaction route but also alters the transition state and desorption energy barriers during the reaction, favoring the methylation reaction and underscoring the distinct functions of Ru.

Published
2024
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24. Preparation of Pt-Based Bimetallic Catalysts and Electrocatalytic Performance for Methanol Oxidation

Author

Li, HongWei, Xu, HanQiao, Qi, JianJun, Da, Hu, Ji, Dong, Zhao, XinHong, and Li, GuiXian

Abstract

The intermediate toxic species COadsproduced by electrocatalytic oxidation of methanol have a high adsorption energy on the surface of Pt active sites and are difficult to convert, which is the main reason for the poisoning and deactivation of Pt electrocatalysts in direct methanol fuel cells. In this study, a series of PtSn/CeO2-CNTs alloy catalysts were prepared by an ethylene glycol hydrothermal reduction method using CeO2-modified carbon nanotubes (CNTs) as the support. The electrochemical properties of a series of PtSn alloy catalysts were measured by using a methanol oxidation reaction (MOR) as a probe reaction. The results show that the excellent electrochemical performance is mainly attributed to the introduction of CeO2and the synergistic effect among the Sn and Pt intermetallic nanoparticles. An in situtransient analysis platform investigated the electrocatalytic oxidation path of methanol molecules at the surface and interface of Pt100-CNTs and Pt42Sn58/CeO2-CNTs catalysts. It was clear that methanol was converted by the CO path, and the introduction of Sn and CeO2synergistically promoted the rapid conversion of intermediate toxic species COads, which effectively improved the activity and stability of Pt catalysts and accelerated the MOR rate. It provides a new idea and basis for the rational design and optimization of Pt electrocatalysts.

Published
2024
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27. Lead-free perovskite/ZnO heterostructure for flexible visible-blind ultraviolet photodetection.

Author

Zhao, Xinhong, Dai, Jinyu, Dong, Jixiang, Tao, Yu, Chen, Jiahuan, Song, Xiaoxian, Fu, Zhendong, Sun, Wenbao, and Yan, Zaoxue

Subjects
*QUANTUM dots, *ZINC oxide, *OPTOELECTRONIC devices, *ELECTRON mobility, *ELECTRON transport, *ARTIFICIAL implants, *PEROVSKITE
Abstract

With the increasing demand for wearable, portable, and implantable optoelectronic devices, flexible photodetectors have become the hotspots of scientific pursuit. In this work, a flexible heterostructure photodetector was fabricated through a combination of perovskite CsCu2I3 nanorods and ZnO quantum dots by a facile solution method. The heterostructure combines the good bending resistance, low dark current, and excellent photoelectric conversion efficiency of CsCu2I3 nanorods with the high electron mobility of ZnO quantum dots; CsCu2I3 NRs act as the light compensating material and hole collector, while ZnO serves as an electron transport channel. This combination results in stronger UV absorption and reduced influence of visible light, achieving ultraviolet-to-visible rejection ratios of as high as 8 × 102. The photodetector exhibits superior performance in the visible-blind ultraviolet region, boasting an on–off ratio of 102, a tenfold increase compared to single-component CsCu2I3 NR photodetectors. Its responsivity and specific detectivity, at 1.62 A/W and 4.13 × 1011 Jones, respectively, outperform the single-component CsCu2I3 NRs by 40 and 23 times and surpass the single-component ZnO photodetectors by 102 times. The response time is about 50% shorter than that of the single-component CsCu2I3 and ZnO photodetectors. This photodetector also shows excellent flexibility and environmental and mechanical stability after a series of sharp bends. The results indicate that the CsCu2I3/ZnO heterostructure provides a promising alternative for high-performance flexible UV optoelectronics. [ABSTRACT FROM AUTHOR]

Published
2024
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35. Understanding the Impact of Peripheral Substitution on the Activity of Co Phthalocyanine in Sulfur Reduction Catalysis.

Author

Zhao, Xinhong, Zhang, Yukun, Liu, Weizhe, Zheng, Zhiqiang, Fu, Zhanghua, Chen, Chuanzhong, and Hu, Cheng

Subjects
*SULFUR, *CATALYSIS, *LITHIUM sulfur batteries, *ELECTRONIC modulation, *ELECTRIC potential, *AMINO group, *SULFUR cycle
Abstract

Catalytic materials are effective in promoting sulfur utilization in lithium‐sulfur batteries. Co phthalocyanine (CoPc) presents a unique planner single‐molecular structure with a highly active Co‐N4 center for sulfur reduction catalysis. The high flexibility of phthalocyanines offers rich opportunities for electronic structure modulation toward enhanced catalytic activities. To guide future design and screening, this study aims to understand the impact of peripheral substitution, the most common method to obtain CoPc derivatives, by examining two typical substituents: the electron‐withdrawing nitro and electron‐donating amino groups. Co tetranitrophthalocyanine (CoTnPc) presents a significantly higher activity in promoting the liquid‐solid transition process than Co tetraaminophthalocyanine (CoTaPc). Substitution alters the stable binding geometry of Li2S4 by influencing the electrostatic potential and Li─bond, making the Co─S bond energetically favorable with the bridging S atoms on CoTnPc. CoTnPc also enables a greater electron donation from the S 3pz orbital to the singly occupied Co 3dz2${d}_{{z}^2}$ orbital, significantly weakening the bridging S─S bond to enhance the reactivity of Li2S4 for the subsequent liquid‐solid transition. A framework of theoretical calculation is tested, providing descriptors for the screening of related materials. The potential of CoPc derivatives is demonstrated by pouch cells with CoTnPc under high sulfur loading and limited electrolyte addition. [ABSTRACT FROM AUTHOR]

Published
2024
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47. Progress in AMS measurement of U isotope ratios in nanogram U samples

Author

Dong, Kejun, He, Ming, Wang, Chen, Zhao, Xinhong, Li, Lili, Zhao, Yonggang, Wang, Xianggao, Shen, Hongtao, Wang, Xiaoming, Pang, Fangfang, Xu, Yongning, Zhao, Qingzhang, Dou, Liang, Yang, Xuran, Wu, Shaoyong, Lin, Deyu, Li, Kangning, You, Qubo, Bao, Yiwen, Hu, Yueming, Xia, Qingliang, Yin, Xinyi, and Jiang, Shan

Published
2015
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