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Howe, Jane Y.

Publications and source records attributed to Howe, Jane Y..

8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

New black indium oxide—tandem photothermal CO 2 -H 2 methanol selective catalyst

It has long been known that the thermal catalyst Cu/ZnO/Al 2 O 3 (CZA) can enable remarkable catalytic performance towards CO 2 hydrogenation for the reverse water-gas shift (RWGS) and methanol synthesis reactions. However, owing to the direct competition between these reactions, high pressure and high hydrogen concentration (≥75%) are required to shift the thermodynamic equilibrium towards methanol synthesis. Herein, a new black indium oxide with photothermal catalytic activity is successfully prepared, and it facilitates a tandem synthesis of methanol at a low hydrogen concentration (50%) and ambient pressure by directly using by-product CO as feedstock. The methanol selectivities achieve 33.24% and 49.23% at low and high hydrogen concentrations, respectively.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Methods of forming nano-catalyst material for fabrication of anchored nanostructure materials

Methods of producing a nano-catalyst material including forming a plurality of nano-scale features on a surface of a substrate material. The nano-catalyst material may be used for forming anchored nanostructure materials by heating the nano-catalyst material under a protective atmosphere to a temperature ranging from about 450° C. to about 1500° C. and exposing the heated nano-catalyst to an organic vapor to affix a separate nanostructure to each of the plurality of nano-scale features. The nano-scale features may be formed on the surface of the substrate material by mechanical or thermal processes.

Menchhofer, Paul A.↗
DOE OSTI2021

Gold-in-copper at low *CO coverage enables efficient electromethanation of CO 2

The renewable-electricity-powered CO 2 electroreduction reaction provides a promising means to store intermittent renewable energy in the form of valuable chemicals and dispatchable fuels. Renewable methane produced using CO 2 electroreduction attracts interest due to the established global distribution network; however, present-day efficiencies and activities remain below those required for practical application. Here we exploit the fact that the suppression of *CO dimerization and hydrogen evolution promotes methane selectivity: we reason that the introduction of Au in Cu favors *CO protonation vs. C-C coupling under low *CO coverage and weakens the *H adsorption energy of the surface, leading to a reduction in hydrogen evolution. We construct experimentally a suite of Au-Cu catalysts and control *CO availability by regulating CO 2 concentration and reaction rate. This strategy leads to a 1.6× improvement in the methane:H 2 selectivity ratio compared to the best prior reports operating above 100 mA cm -2 . We as a result achieve a CO 2 -to-methane Faradaic efficiency (FE) of (56 ± 2)% at a production rate of (112 ± 4) mA cm -2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Evaporation due to infrared heating and natural convection

The results obtained from a drying experiment under infrared heating are compared to those obtained from correlations for the mass transfer coefficients, which are commonly used to obtain evaporation rates for drying applications. It was shown that the mass transfer coefficients evaluated by natural convection correlations are approximately ten times lower than those measured under infrared (IR) exposure. In this work, an attempt to explain this discrepancy, which has been also observed in other studies and explained on the basis of thermal radiation effects, optical properties of NMP are presented and the implications of the IR and near infrared (NIR) spectrum on the thermal radiation effects and ensuing evaporation rates are discussed. The results show that expected raise in the film temperature, which would be due to the thermal radiation effects, cannot be used to describe the measured evaporation rates for this solvent. Therefore, this study provides important evaporation mass flux data, which cannot be predicted using traditional correlations, for the design of IR assisted drying systems used in membrane fabrication.

42 ENGINEERING↗
DOE OSTI2019

Constraining CO coverage on copper promotes high-efficiency ethylene electroproduction

The availability of inexpensive industrial CO gas streams motivates efficient electrocatalytic upgrading of CO to higher-value feedstocks such as ethylene. However, the electrosynthesis of ethylene by the CO reduction reaction (CORR) has suffered from low selectivity and energy efficiency. Here we find that the recent strategy of increasing performance through use of highly alkaline electrolyte—which is very effective in CO 2 RR—fails in CORR and drives the reaction to acetate. We then observe that ethylene selectivity increases when we constrain (decrease) CO availability. Using density functional theory, we show how CO coverage on copper influences the reaction pathways of ethylene versus oxygenate: lower CO coverage stabilizes the ethylene-relevant intermediates whereas higher CO coverage favours oxygenate formation. We then control local CO availability experimentally by tuning the CO concentration and reaction rate; we achieve ethylene Faradaic efficiencies of 72% and a partial current density of >800 mA cm -2 . The overall system provides a half-cell energy efficiency of 44% for ethylene production.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Nano-material

A fluffy nano-material and method of manufacture are described. At 2000× magnification the fluffy nanomaterial has the appearance of raw, uncarded wool, with individual fiber lengths ranging from approximately four microns to twenty microns. Powder-based nanocatalysts are dispersed in the fluffy nanomaterial. The production of fluffy nanomaterial typically involves flowing about 125 cc/min of organic vapor at a pressure of about 400 torr over powder-based nano-catalysts for a period of time that may range from approximately thirty minutes to twenty-four hours.

Menchhofer, Paul A.↗