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Dang, Dai

Publications and source records attributed to Dang, Dai.

8 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Structurally Ordered Fe 3 Pt Nanoparticles on Robust Nitride Support as a High Performance Catalyst for the Oxygen Reduction Reaction

Abstract The commercialization of fuel cell technologies requires a significant reduction in the amount of expensive platinum catalyst in the cathode while still maintaining high catalytic activity and stability. Herein a cost‐effective, highly durable, and efficient catalyst consisting of ordered Fe 3 Pt nanoparticles supported by mesoporous Ti 0.5 Cr 0.5 N (Fe 3 Pt/Ti 0.5 Cr 0.5 N) is demonstrated. The Fe 3 Pt/Ti 0.5 Cr 0.5 N catalyst exhibits a five‐fold increase in mass activity relative to a Pt/C catalyst at 0.9 V for the oxygen reduction reaction. More importantly, the catalyst shows a minimal loss of activity after 5000 potential cycles (9.7%). The enhanced activity of the ordered Fe 3 Pt/Ti 0.5 Cr 0.5 N catalyst, in combination with its enhanced stability, makes it very promising for the development of new cathode catalysts for fuel cells.

Liu, Quanbing↗
DOE OSTI2018

A Facile and Environmentally Friendly One-Pot Synthesis of Pt Surface-Enriched Pt-Pd(x)/C Catalyst for Oxygen Reduction

Platinum surface-enriched bimetallic PtPd nanoparticles are synthesized via a facile and eco-friendly approach. Significantly different formation processes of single Pt, Pd, and bimetallic PtPd nanoparticles under various conditions have been monitored by UV-visible spectra. The size of the bimetallic Pt-Pd nanoparticles has been found to be significantly affected by the pH of the starting precursor solutions. Uniform bimetallic Pt-Pd nanoparticles with an average diameter of ~3 nm are formed in the basic solutions; however, the particle size can be as large as 11 nm when synthesized in acidic media. The detailed morphology, composition, and structure of the carbon-supported bimetallic Pt-Pd electrocatalysts have been extensively characterized and correlated with their electrochemical properties as evaluated using cyclic voltammetry and single-cell test. The formation of Pt surface-enriched Pt-Pd bimetallic nanoparticles has been confirmed by X-ray photoelectron spectroscopy and has been interpreted by the exclusively reduced Pt around the newly formed Pd nuclei due to the catalytic action of Pd, which in turn curbs the unfavorable growth of the bimetallic nanoparticles. The electrochemical tests indicate that the optimized Pt-Pd/C with reduced cost exhibits competitive catalytic performance toward oxygen reduction reaction and superior tolerance to methanol over the state-of-the-art Pt/C.

Chemistry↗
DOE OSTI2017

A durable polyvinyl butyral-CsH 2 PO 4 composite electrolyte for solid acid fuel cells

We report a composite electrolyte membrane composed of polyvinyl butyral (PVB) and CsH 2 PO 4 has been prepared via a facile and cost-effective method for solid acid fuel cells. The effect of PVB content on conductivity, mechanical integrity, and fuel cell performance is investigated. A minimum amount of 3 wt% PVB in the CsH 2 PO 4 -based composite electrolyte not only offers the required mechanical integrity but also allows high conductivity (~28 mS cm -1 at 260 °C). Single cells based on the composite electrolytes demonstrate a peak power density of 108 mW cm -2 at 260 °C. Almost no degradation in electrochemical performance could be observed during the stability test for 10 h and three thermal-cycling test in H 2 /O 2 fuel cell, indicating the promising application of the composite electrolyte in solid acid fuel cells.

25 ENERGY STORAGE↗
DOE OSTI2016

A Highly Efficient and Robust Nanofiber Cathode for Solid Oxide Fuel Cells

(La 0.6 Sr 0.4 ) 0.95 Co 0.2 Fe 0.8 O 3+δ nanofiber cathode prepared by electrospinning demonstrates excellent oxygen reduction reaction (ORR) activity, as reflected by reduced polarization resistance and diminished activation energy. ORR enhancement can be attributed to the efficient mass/charge transfer. Furthermore, the nanofiber electrode shows good durability under operation conditions of solid oxide fuel cells.

25 ENERGY STORAGE↗