RSC Advances
·
2016
·Vol. 6
·期 74
·70303-70310
·
IF 3.289
Hongxing Zhang,Yiwei Zhang,Yuming Zhou,Chao Zhang,Xiaoli Sheng,Shuo Zhao,Jiasheng Fang,Mingyu Zhang
This article reports a facile and controllable one-step method to construct Pt@hollow mesoporous SiO2 (Pt@HMSiO2) nanoparticles (NPs). To enhance the catalytic activity, cerium species were impregnated into Pt@HMSiO2 NPs, fabricating highly reactive Pt–CeO2@HMSiO2 NPs. To verify the successful synthesis of the Pt@HMSiO2 and Pt–CeO2@HMSiO2 NPs, and study the influence of CeO2 species on the catalytic performance, the as-prepared NPs were characterized by several techniques, including SEM, TEM, EDX, FTIR, XRD, BET and UV-vis analyses. In this work, the reduction of 4-NP was employed as a model reaction to test the catalytic performance. Compared to Pt@HMSiO2, the Pt–CeO2@HMSiO2 NPs show higher catalytic activity, because of the co-catalysis of CeO2 NPs. However, the excess amount of CeO2 NPs would lead to a lower catalytic activity, due to the blocking of the catalyst pore. In addition, the Pt–CeO2@HMSiO2 NPs show a high thermal stability due to the protection of the SiO2 shell. Meanwhile, we have also used the reaction of propane dehydrogenation to further verify the excellent catalytic stability of Pt–CeO2@HMSiO2 NPs. This strategy is novel, albeit efficient, and can be extended to the preparation of other nanocatalysts.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
Materials Express
·
2019
·Vol. 9
·期 4
·281-290
·
IF 1.465
Dongmulati Naziermu,Maimaitiyiming Xieraili,Maimaiti Yuemaierjiang
A novel and very effective method to improve the electrochemical performance of fuel cells catalysts was developed. First, different sizes of polypyrimidine coated carbon nanotubes (Polypyrimidine/CNT) were separated by different centrifugal speeds (7, 18, 35, 72 g), and platinum particles
were deposited on the hybrids to prepare fuel cell catalysts. The catalyst has good catalytic performance when the composite is sized-controlled at a speed of 18 g. Then, the pure carbon nanotubes in the Pt based polyaniline coated single-walled carbon nanutubes catalyst (PANI/CNT/Pt) were
replaced with the size-controlled composite at a centrifugal speed of 18 g to prepare a binary catalyst (PANI/polypyrimidine/CNT 18/Pt). The electrochemical active area (ECSA) value of the catalyst prepared by this method was successfully increased by about 2 times compared with PANI/CNT/Pt,
and the oxidation of methanol of the catalyst were effectively improved.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2019
·Vol. 33
·期 11
·e5217
·
IF 3.259
Luyao Ma,Chenxin Liu,Qingxin Guan,Wei Li
The effects of particle size and kinetics of Pt/activated carbon (AC) catalysts on catalytic oxidation of formaldehyde (HCHO) were investigated. AC, f-SiO 2 and MCM-41 were used as supports to prepare low-Pt-content catalysts using H 2 reduction. Pt/AC catalyst shows the highest activity with the largest Pt particle size. By contrast, 0.1 wt% Pt/AC reduced using KBH 4 has much higher activity than that reduced using H 2 , which can oxidize HCHO completely over 6000 ppm at 60°C in a fixed bed reactor. Transmission electron microscopy and X-ray photoelectron spectroscopy results indicate that Pt/AC-KBH 4 has larger Pt particles and lower valence state than Pt/AC-H 2 , which may be attributed to the ligand effect between Pt 4+ and the AC support. The result of O 2 temperature-programmed oxidation suggests that highly dispersed Pt 4+ ions have stronger interaction with AC support and thus are harder to be reduced by H 2 . Furthermore, Pt/AC is structure-sensitive and larger-sized Pt particles result in a high conversion of HCHO. Investigation of kinetics indicated that it is a zero-order reaction for such a high HCHO concentration condition for Pt/AC-KBH 4 .
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2019
·
IF 2.584
Lili Geng,Jianjun Gong,Guilong Qiao,Songshou Ye,Jinbao Zheng,Nuowei Zhang,Binghui Chen
Pt(NH3)4(NO3)2, Pt(NH3)4(Ac)2, (NH4)2PtCl4, and H2PtCl6 were used to prepare Pt/SAPO-11 catalysts to investigate the effect of Pt precursors on the hydroisomerization of n-dodecane. The catalyst derived from Pt(NH3)4(NO3)2 displays the best hydroisomerization activity and selectivity among these precursors. The hydroisomerization conversion of n-dodecane is affected by the platinum particle size, platinum dispersion, the location of platinum, and the valence state of platinum. The selectivity of n-dodecane is determined by the number of Brønsted acid sites and Pt crystal planes. These conclusions are verified by combining transmission electron microscopy, high-resolution transmission electron microscopy, hydrogen temperature programmed reduction, NH3-temperature programmed desorption, and Py-IR studies. The catalyst prepared with Pt(NH3)4(NO3)2 as the precursor exhibits the smallest platinum particle size and the highest platinum dispersion. Most of the platinum particles are supported on the external surface of SAPO-11 with the Pt(111) crystal face. Such a catalyst also possesses a suitable number of Brønsted acid sites and then displays the best catalytic performance. Obviously, the use of various precursors for the Pt-based catalyst can significantly affect the performance of Pt/SAPO-11 for the hydroisomerization of n-dodecane.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Lipeng Guo,Jihui Yao,Haibo Zhu
Methylcyclohexane (MCH) dehydrogenation for H 2 production is a promising route in liquid organic hydrogen carriers technology. However, there are few reports on the influence of Pt size on methylcyclohexane dehydrogenation under different reaction atmospheres. In this study, a series of Pt/Al 2 O 3 catalysts with Pt particle sizes ranging from 0.67 to 1.26 nm were prepared via the impregnation method. The influences of Pt particle size on MCH dehydrogenation under H 2 and N 2 atmospheres were investigated. The toluene (TOL) product adsorbed on Pt site has a significant effect on the activity and stability of Pt/Al 2 O 3 for MCH dehydrogenation. Under N 2 atmosphere, the poisoning of Pt/Al 2 O 3 by toluene leads to a low activity in this reaction. By contrast, under H 2 atmosphere, the adsorption of toluene can be effectively inhibited by H 2 , and thus an enhanced catalytic performance can be achieved. The catalyst with Pt size of 0.67 nm exhibits a high turnover frequency (TOF) of 33,530 mol H2 ·mol Pt −1 ·h −1 , corresponding to a H 2 evolution rate of 2,865 mmol·g Pt −1 ·min −1 . These findings provide a deeper understanding of the dependence of catalyst structure and reaction conditions on MCH dehydrogenation, offering fundamental guidance for the design of efficient catalysis system for MCH dehydrogenation.
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Zhenli Xiang,Chaofan Ma,Dongchuang Wan,Heng Huang,Jiaxin Yu,Yongyue Yao,Chunyu Yin,Yebin Zhou,Chunshan Lu,Xiaonian Li
Continuous technology is the future development direction of selective hydrogenation synthesis for fine chemicals. To achieve high hydrogenation performance at atmospheric pressure, it is necessary to construct a suitable microenvironment on the surface of the catalyst to achieve effective mass transfer at the gas–liquid–solid three-phase interface. Ultrafine metal clusters were obtained using Dicyandiamide (DICY) in the hydrothermal process. Subsequently, the alkylsilane was added to construct a respiratory-like microenvironment. (The microenvironment is similar to the respiratory channels, which regulate the entry and exit of substances rhythmically and dynamically, ensuring the continuous and efficient catalytic reaction). The continuous selective hydrogenation of nitroaromatics over Pt-AC(DICY)-C8 in a fixed-bed microreactor showed excellent hydrogenation ability, with the conversion of 2-chloro-4-nitrotoluene reaching 100% and the 3-chloro-4-methylaniline selectivity exceeding 99% within 80 h. The excellent hydrogenation performance is attributed to the highly dispersed Pt clusters, which increase the active sites. The respiratory-like microenvironment promotes the mass transfer of H2 and hydrophobic reactants, increasing the H2 concentration surrounding the Pt active site and the enrichment of reactants. Simultaneously, the respiratory-like microenvironment is conducive to the rapid diffusion of hydrophilic products and prevents excessive hydrogenation. This strategy shows the potential to improve the efficiency and stability of the continuous catalytic hydrogenation reaction.
研究领域:
催化
·
化学工程
·
纳米技术
·
材料科学
·
有机合成
·
反应工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）