GREEN CHEMISTRY
·
2017
·Vol. 19
·期 9
·2201-2211
·
IF 9.125
Wenxiu Cao,Wenhao Luo,Hongguang Ge,Yang Su,Aiqin Wang,Tao Zhang
The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is a crucial reaction included in many biorefinery schemes for the production of renewable chemicals and fuels. The development of highly stable supported Ru-based catalysts in the polar protic liquid phase under hydrothermal conditions is still a major challenge. Here, we prepared a 0.85 wt% Ru/ZrO2@C catalyst using a new stabilization strategy based on the UiO-66 (Zr-MOF) material. The catalytic performance of this Ru/ZrO2@C in LA-to-GVL was tested and compared with commercial 5 wt% Ru/C at 10 bar H2, 413 K in water and also in high protic aqueous solution (pH = 1). The full conversion of LA and quantitative yield of GVL were achieved with both catalysts. However, the 5 wt% Ru/C showed poor resistance to deactivation already after the first run. ICP, XPS, HRTEM, AC-STEM, TPR and physisorption data showed that quick deactivation of Ru/C was mainly caused by the leaching of ruthenium in addition to the loss of surface area via carbonaceous deposition in micro-pores. In contrast, the self-prepared Ru/ZrO2@C catalyst showed no apparent drop in catalytic performance either in water or in high protic aqueous solution upon multiple recycling, and no leaching of ruthenium was found even under harsh conditions (pH = 1). Remarkably, in the Ru/ZrO2@C catalyst, Ru (probable single-atom) was highly dispersed on nanotetragonal ZrO2 (3.3 nm), embedded in the amorphous carbon, and no apparent Ru nanoclusters were observed even after reactions. TPR results indicated that this excellent stability might be attributed to strong metal–support interaction between Ru and nanotetragonal ZrO2.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 23
·15934-15941
·
IF 3.9
Xiaoping Chen,Xianfei Wang,Wei Liu,Hui Tian,Yupeng Du,Haisheng Wei,Linsheng Tang
1-Butene, as one of the widely used chemical raw materials, can be produced by the double bond isomerization of 2-butene. However, the current yield of the isomerization reaction is only up to 20% or so. It is therefore an urgent issue to develop novel catalysts with higher performances. In this work, a high-activity ZrO2@C catalyst that is derived from UiO-66(Zr) is fabricated. The catalyst is prepared by calcining the precursor UiO-66(Zr) at high temperature in nitrogen, and characterized by XRD, TG, BET, SEM/TEM, XPS and NH3-TPD. The results demonstrate that the calcination temperature has significant influences on the catalyst structure and performance. Regarding the catalyst ZrO2@C-500, the selectivity and yield of 1-butene are 94.0% and 35.1%, respectively. The high performance is due to multiple aspects, including the inherited octahedral morphology from parent UiO-66(Zr), suitable medium-strong acidic active sites and high surface area. The present work will lead to a better understanding of the ZrO2@C catalyst and guide the rational design of high-activity catalysts for the double bond isomerization of 2-butene to 1-butene.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Chemistry-An Asian Journal
·
2018
·Vol. 14
·期 3
·416-421
·
IF 3.692
Qian Wang,Wei Sun,Tianying Xie,Limei Cao,Ji Yang
Graphical Carbon-coated catalysts : Octahedral Pt/ZrO 2 @C, prepared by direct carbonization of the precursor UiO-66-NH 2 (a zirconium-based metal–organic framework), exhibits improved catalytic activity for selective catalytic reduction with H 2 at ambient temperature, compared with that of other platinum-based catalysts with porous materials as supports (see figure). Selective catalytic reduction (SCR) of NO x with H 2 as a reductant is the most promising denitration technology at low temperature. Achieving the conversion of NO x into N 2 at ambient temperature not only prolongs the service life of the catalyst, but also provides more freedom for the arrangement of denitration units throughout the flue gas treatment equipment. However, the development of highly efficient, stable, and environmentally benign supported platinum-based catalysts for H 2 -SCR at ambient temperature is still a major challenge. Herein, a 0.5 wt % Pt/ZrO 2 @C catalyst, which was composed of carbon-coated octahedral ZrO 2 with highly dispersed Pt particles, was prepared by using a new stabilization strategy based on UiO-66-NH 2 (a zirconium metal–organic framework) as a template. The catalytic performance of this Pt/ZrO 2 @C in H 2 -SCR was tested and confirmed to achieve near 100 % NO x conversion at 90 °C. Also, 70 % N 2 selectivity of the catalyst was achieved. The morphology, structure, and porous properties of the as-synthesized nanocomposites were characterized by using data obtained from field-emission SEM, TEM, XRD, Raman spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and N 2 adsorption–desorption isotherms. The results show that residual carbon formed by pyrolysis treatment is coated on octahedral ZrO 2 , and effectively prevents the agglomeration of platinum particles on the surface.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）