Palladium-Coated Platinum Powders with Tunable, Nanostructured Surfaces for Applications in Catalysis

Journal Article · Fri Dec 06 00:00:00 EST 2019 · ACS Applied Nano Materials

DOI:https://doi.org/10.1021/acsanm.9b02090· OSTI ID:1634805

Gurung, Sita ^[1]; Robinson, David B. ^[2]; Cappillino, Patrick J. ^[1]

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1. Univ. of Massachusetts, Dartmouth, MA (United States). Dept. of Chemistry and Biochemistry
2. Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Simultaneous control of nanoscale surface morphology and composition remains a challenge in preparing bimetallic catalysts, particularly at the large scale required for industrial application and with high-surface-area substrates. Atomic layer electroless deposition (ALED) is a scalable approach to prepare surface-modified metal powders in which elements more noble than the surface hydrides of the substrate metal are deposited layer-by-layer in a surface-limited fashion. In this paper, we demonstrate that high-surface-area Pt powder is a viable substrate for controlled deposition of Pd adlayers using this technique, with the potential for large-scale preparation, for use in electrocatalytic and catalytic applications such as fuel cells and functionalization of petrochemical feedstocks. Two different growth mechanisms have been proposed based on bulk and surface Pd atomic fractions obtained from atomic absorption spectroscopy and X-ray photoelectron spectroscopy, respectively. Further, spectral simulations were performed to strengthen the proposed growth mechanisms, favoring conformal growth in initial deposition followed by island formation in subsequent cycles. Observation of multiple pathways suggests a means of controlling adlayer surface morphology of ALED materials, in which an initial cycle of deposition sets the fractional coverage and subsequent cycles tune adlayer thickness.

• Research Organization: Sandia National Laboratories (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: National Science Foundation (NSF); US Army Research Laboratory (USARL); USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000; NA0003525
• OSTI ID: 1634805
• Report Number(s): SAND--2020-5696J; 686459
• Journal Information: ACS Applied Nano Materials, Journal Name: ACS Applied Nano Materials Journal Issue: 1 Vol. 3; ISSN 2574-0970
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALD
ALED
electroless
galvanic replacement
growth mechanism
near-surface alloy
surface alloy
surface hydride
surface-limited redox replacment (SLRR)