東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Catalytic Conversion of Short-Chain ...

Wang, Chongyang.

FindBook

Google Book

Amazon

博客來

Catalytic Conversion of Short-Chain Alcohols on Atomically Dispersed Au and Pd Supported on Nanoscale Metal Oxides.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Catalytic Conversion of Short-Chain Alcohols on Atomically Dispersed Au and Pd Supported on Nanoscale Metal Oxides./
作者:	Wang, Chongyang.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2016,
面頁冊數:	195 p.
附註:	Source: Dissertation Abstracts International, Volume: 77-11(E), Section: B.
Contained By:	Dissertation Abstracts International77-11B(E).
標題:	Chemical engineering. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10118633
ISBN:	9781339799629

Catalytic Conversion of Short-Chain Alcohols on Atomically Dispersed Au and Pd Supported on Nanoscale Metal Oxides.
Wang, Chongyang.

Catalytic Conversion of Short-Chain Alcohols on Atomically Dispersed Au and Pd Supported on Nanoscale Metal Oxides. - Ann Arbor : ProQuest Dissertations & Theses, 2016 - 195 p.

Source: Dissertation Abstracts International, Volume: 77-11(E), Section: B.

Thesis (Ph.D.)--Tufts University, 2016.

With the development of technologies for cellulosic biomass conversion to fuels and chemicals, bio-alcohols are among the main alternative feedstocks to fossil fuels. The research pursued in my thesis was the investigation of gold and palladium as catalysts for the application of short aliphatic alcohols to hydrogen generation and value-added chemicals production. Specifically, selective methanol steam reforming and non-oxidative ethanol dehydrogenation to hydrogen and acetaldehyde were investigated in this thesis work. A major aim of the thesis was to develop atomically efficient catalysts with tuned surface chemistry for the desired reactions, using suitable synthesis methods.

ISBN: 9781339799629Subjects--Topical Terms:

560457
Chemical engineering.

Catalytic Conversion of Short-Chain Alcohols on Atomically Dispersed Au and Pd Supported on Nanoscale Metal Oxides.
LDR:06296nmm a2200349 4500 001 2119180
005 20170619080558.5
008 180830s2016 ||||||||||||||||| ||eng d
020 $a 9781339799629
035 $a (MiAaPQ)AAI10118633
035 $a AAI10118633
040 $a MiAaPQ $c MiAaPQ
100 1 $a Wang, Chongyang. $3 3281035
245 1 0 $a Catalytic Conversion of Short-Chain Alcohols on Atomically Dispersed Au and Pd Supported on Nanoscale Metal Oxides.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2016
300 $a 195 p.
500 $a Source: Dissertation Abstracts International, Volume: 77-11(E), Section: B.
500 $a Adviser: Maria Flytzani-Stephanopoulos.
502 $a Thesis (Ph.D.)--Tufts University, 2016.
520 $a With the development of technologies for cellulosic biomass conversion to fuels and chemicals, bio-alcohols are among the main alternative feedstocks to fossil fuels. The research pursued in my thesis was the investigation of gold and palladium as catalysts for the application of short aliphatic alcohols to hydrogen generation and value-added chemicals production. Specifically, selective methanol steam reforming and non-oxidative ethanol dehydrogenation to hydrogen and acetaldehyde were investigated in this thesis work. A major aim of the thesis was to develop atomically efficient catalysts with tuned surface chemistry for the desired reactions, using suitable synthesis methods.
520 $a Methanol steam reforming (SRM) for hydrogen production has recently been investigated on gold catalysts to overcome the drawbacks of copper catalysts (deactivation, pyrophoricity). Previous work at Tufts University has shown that both CeO2 and ZnO are suitable supports for gold. In this thesis, nanoscale composite oxides ZnZrOx were prepared by a carbon hard-template method, which resulted in homogeneous distribution of Zn species in the matrix of ZrO2. Tunable surface chemistry of ZnZrO x was demonstrated by varying the Zn/Zr ratio to suppress the strong Lewis acidity of ZrO2, which leads to undesired production of CO through methanol decomposition. With atomic dispersion of gold, Au/ZnZrO x catalyzes the SRM reaction exclusively via the methanol self-coupling pathway up to 375°C. The activity of Au/ZnZrOx catalysts was compared to Au/TiO2, which is another catalyst system demonstrating atomic dispersion of gold. Similarity in the apparent activation energy of SRM on all the supported gold catalysts studied in this thesis and in the literature further confirms the same single-site Au-Ox-MO centers as active sites for SRM with indirect effects of the supports exploited.
520 $a With this fundamental understanding of gold-catalyzed C1 alcohol reforming, the Au/ZnZrOx catalyst was evaluated for the dehydrogenation of ethanol. Bare ZnZrOx activate ethanol conversion in the range of 280-300°C and produce undesired ethylene as product of ethanol dehydration, whereas, addition of small amount of gold (<1wt.%) was found to significantly change the product distribution in the low-temperature range (200°C-350°C). As gold passivates the strong Bronsted acid sites of ZrO2 and selectively facilitates the dehydrogenation of ethanol at low-temperature, a wide temperature range was found between the production of acetaldehyde (dehydrogenation products) and ethylene (dehydration product), which can be harnessed for the industrial application. Interestingly, the steam reforming of ethanol did not take place in the low-temperature region, thus the selectivity to acetaldehyde and hydrogen was 100% even in the presence of water.
520 $a In addition to gold, palladium was also studied in this thesis work on the ZnZrOx composite oxides, and its activity and selectivity were compared to Au/ZnZrOx. Monometallic Pd catalyzes the decomposition of methanol and ethanol, resulting in different product distribution for C 1-C2 alcohol reactions. With ZnZrOx employed as the catalyst support in this thesis work, the finely dispersed ZnO species in ZrO2 were found to alloy with the supported palladium under reduction treatment. Alloying with Zn tunes the chemistry of Pd to catalyze the SRM reaction through the methanol coupling mechanism, shutting off the undesired methanol decomposition pathway. A preliminary study of the Pd/ZnZrO x system for ethanol dehydrogenation also demonstrated the modification of Pd when in the PdZn alloy form. Different from the monometallic Pd catalyst, which primarily catalyzes the C-C bond scission of ethanol, high selectivity to ethanol dehydrogenation products was found on PdZn, over the temperature range of 200-400°C. Formation of the PdZn alloy broadens the application of Pd and potentially other Group VIII metals for selective alcohol conversion reactions.
520 $a In summary, this thesis work has investigated two noble metals Au and Pd from Group IB and Group VIII, respectively, for methanol and ethanol alcohol reforming reactions employing a novel ZnZrOx composite oxide as a platform catalyst support. Comprehensive study of Au catalyst has deepened our understanding of atomically dispersed Au anchored on various supports through oxygen bonds as the active sites for alcohol reforming reactions, and showed the support effect to be indirect, serving as the carrier and stabilizer of the gold species. For Pd, the Zn species of the composite oxide is necessary to modify the Pd catalyst and the PdZn alloy gives it the desired Au-like properties. Full characterization of the catalysts used here by ICP, XPS, XRD, FTIR and STEM imaging was conducted throughout the thesis to identify the stable species and correlate the catalyst performance with its composition and morphology. Surface acidity titration by isopropanol temperature-programmed desorption/mass spectrometry (IPA-TPD/MS) and pyridine-IR adsorption/desorption was conducted in parallel to temperature-programmed surface reaction (TPSR) studies and products from isothermal steady-state reactions were monitored online by mass spectrometry.
590 $a School code: 0234.
650 4 $a Chemical engineering. $3 560457
650 4 $a Nanoscience. $3 587832
650 4 $a Chemistry. $3 516420
690 $a 0542
690 $a 0565
690 $a 0485
710 2 $a Tufts University. $b Chemical and Biological Engineering. $3 1286908
773 0 $t Dissertation Abstracts International $g 77-11B(E).
790 $a 0234
791 $a Ph.D.
792 $a 2016
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10118633