期刊
ACS CATALYSIS
卷 11, 期 12, 页码 7193-7209出版社
AMER CHEMICAL SOC
DOI: 10.1021/acscatal.1c01136
关键词
ethanol; butenes; butadiene; selective hydrogenation; catalysis; single-atom alloy; zeolite
资金
- U.S. Department of Energy (DOE), Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (BETO) [DE-AC05-00OR22725]
- Center for Nanophase Materials Sciences (CNMS) - Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. DOE
- DOE
- DOE Office of Science by Argonne National Laboratory [DE-AC02-06CH11357]
- National Science Foundation [EEC1647722]
- Bioenergy Technologies Office of Energy Efficiency & Renewable Energy
- U.S. DOE, EERE, Bioenergy Technologies Office
- UT-Battelle, LLC
- Chemical Catalysis for Bioenergy (ChemCatBio) Consortium, a member of the Energy Materials Network
A multifunctional catalyst system composed of Zn-Y/Beta and single-atom alloy (SAA) Pt-Cu/Al2O3 has been reported, which selectively catalyzes ethanol-to-olefin valorization without cofed hydrogen, forming butenes as the primary olefin products. This catalyst system offers a new pathway for the production of low-carbon middle-distillate transportation fuels, showing high selectivity and avoiding costly hydrogen cofeeding requirements.
The selective production of C3+ olefins from renewable feedstocks, especially via C-1 and C-2 platform chemicals, is a critical challenge for obtaining economically viable low-carbon middle-distillate transportation fuels (i.e., jet and diesel). Here, we report a multifunctional catalyst system composed of Zn-Y/Beta and single-atom alloy (SAA) Pt-Cu/Al2O3, which selectively catalyzes ethanol-to-olefin (C3+, ETO) valorization in the absence of cofed hydrogen, forming butenes as the primary olefin products. Beta zeolites containing predominately isolated Zn and Y metal sites catalyze ethanol upgrading steps (588 K, 3.1 kPa ethanol, ambient pressure) regardless of cofed hydrogen partial pressure (0-98.3 kPa H-2), forming butadiene as the primary product (60% selectivity at an 87% conversion). The Zn-Y/Beta catalyst possesses site-isolated Zn and Y Lewis acid sites (at similar to 7 wt % Y) and Bronsted acidic Y sites, the latter of which have been previously uncharacterized. A secondary bed of SAA Pt-Cu/Al2O3 selectively hydrogenates butadiene to butene isomers at a consistent reaction temperature using hydrogen generated in situ from ethanol to butadiene (ETB) conversion. This unique hydrogenation reactivity at near-stoichiometric hydrogen and butadiene partial pressures is not observed over monometallic Pt or Cu catalysts, highlighting these operating conditions as a critical SAA catalyst application area for conjugated diene selective hydrogenation at high reaction temperatures (>573 K) and low H-2/diene ratios (e.g., 1:1). Single-bed steady-state selective hydrogenation rates, associated apparent hydrogen and butadiene reaction orders, and density functional theory (DFT) calculations of the Horiuti-Polanyi reaction mechanisms indicate that the unique butadiene selective hydrogenation reactivity over SAA Pt-Cu/Al2O3 reflects lower hydrogen scission barriers relative to monometallic Cu surfaces and limited butene binding energies relative to monometallic Pt surfaces. DFT calculations further indicate the preferential desorption of butene isomers over SAA Pt-Cu(111) and Cu(111) surfaces, while Pt(111) surfaces favor subsequent butene hydrogenation reactions to form butane over butene desorption events. Under operating conditions without hydrogen cofeeding, this combination of Zn-Y/Beta and SAA Pt-Cu catalysts can selectively form butenes (65% butenes, 78% C3+ selectivity at 94% conversion) and avoid butane formation using only in situ-generated hydrogen, avoiding costly hydrogen cofeeding requirements that hinder many renewable energy processes.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据