1
|
Spencer JA, Barclay M, Gallagher MJ, Winkler R, Unlu I, Wu YC, Plank H, McElwee-White L, Fairbrother DH. Comparing postdeposition reactions of electrons and radicals with Pt nanostructures created by focused electron beam induced deposition. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2410-2424. [PMID: 29234576 PMCID: PMC5704761 DOI: 10.3762/bjnano.8.240] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/18/2017] [Indexed: 05/31/2023]
Abstract
The ability of electrons and atomic hydrogen (AH) to remove residual chlorine from PtCl2 deposits created from cis-Pt(CO)2Cl2 by focused electron beam induced deposition (FEBID) is evaluated. Auger electron spectroscopy (AES) and energy-dispersive X-ray spectroscopy (EDS) measurements as well as thermodynamics calculations support the idea that electrons can remove chlorine from PtCl2 structures via an electron-stimulated desorption (ESD) process. It was found that the effectiveness of electrons to purify deposits greater than a few nanometers in height is compromised by the limited escape depth of the chloride ions generated in the purification step. In contrast, chlorine atoms can be efficiently and completely removed from PtCl2 deposits using AH, regardless of the thickness of the deposit. Although AH was found to be extremely effective at chemically purifying PtCl2 deposits, its viability as a FEBID purification strategy is compromised by the mobility of transient Pt-H species formed during the purification process. Scanning electron microscopy data show that this results in the formation of porous structures and can even cause the deposit to lose structural integrity. However, this phenomenon suggests that the use of AH may be a useful strategy to create high surface area Pt catalysts and may reverse the effects of sintering. In marked contrast to the effect observed with AH, densification of the structure was observed during the postdeposition purification of PtC x deposits created from MeCpPtMe3 using atomic oxygen (AO), although the limited penetration depth of AO restricts its effectiveness as a purification strategy to relatively small nanostructures.
Collapse
Affiliation(s)
- Julie A Spencer
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Michael Barclay
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Miranda J Gallagher
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Robert Winkler
- Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria
| | - Ilyas Unlu
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Yung-Chien Wu
- Department of Chemistry, University of Florida, Gainesville, FL, 32611-7200, USA
| | - Harald Plank
- Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria
- Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
| | - Lisa McElwee-White
- Department of Chemistry, University of Florida, Gainesville, FL, 32611-7200, USA
| | | |
Collapse
|
2
|
Starr DE, Liu Z, Hävecker M, Knop-Gericke A, Bluhm H. Investigation of solid/vapor interfaces using ambient pressure X-ray photoelectron spectroscopy. Chem Soc Rev 2013; 42:5833-57. [DOI: 10.1039/c3cs60057b] [Citation(s) in RCA: 313] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
3
|
Kan HH, Shumbera RB, Weaver JF. Hot precursor reactions during the collisions of gas-phase oxygen atoms with deuterium chemisorbed on Pt(100). J Chem Phys 2007; 126:134704. [PMID: 17430053 DOI: 10.1063/1.2713111] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We utilized direct rate measurements and temperature programmed desorption to investigate reactions that occur during the collisions of gaseous oxygen atoms with deuterium-covered Pt(100). We find that both D2O and D2 desorb promptly when an oxygen atom beam impinges upon D-covered Pt(100) held at surface temperatures ranging from 90 to 150 K, and estimate effective cross sections of 12 and 1.8 A2, respectively, for the production of gaseous D2O and D2 at 90 K. The yields of D2O and D2 that desorb at 90 K are about 13% and 2%, respectively, of the initial D atom coverage, though most of the D2O product molecules (approximately 80%) thermalize to the surface rather than desorb at the surface temperatures studied. Increasing the surface temperature from 90 to 150 K causes the D2O desorption rate to decay more quickly during O atom exposures to the surface and results in lower yields of gaseous D2O. We attribute the production of D2O and D2 in these experiments to reactions involving intermediates that are not thermally accommodated to the surface, so-called hot precursors. The results are consistent with the production of hot D2O involving first the generation of hot OD groups from the reaction O*+D(a)-->OD*, where the asterisk denotes a hot precursor, followed by the parallel pathways OD*+D(a)-->D2O* and OD*+OD(a)-->D2O*+O(a). The final reaction contributes significantly to hot D2O production only later in the reaction period when thermalized OD groups have accumulated on the surface, and it becomes less important at higher temperature due to depletion of the OD(a) concentration by thermally activated D2O production.
Collapse
Affiliation(s)
- Heywood H Kan
- Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611, USA
| | | | | |
Collapse
|
4
|
Fernandez-Ramos A, Miller JA, Klippenstein SJ, Truhlar DG. Modeling the kinetics of bimolecular reactions. Chem Rev 2007; 106:4518-84. [PMID: 17091928 DOI: 10.1021/cr050205w] [Citation(s) in RCA: 393] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Antonio Fernandez-Ramos
- Departamento de Quimica Fisica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | | | | | | |
Collapse
|
5
|
Wang B. Recent development of non-platinum catalysts for oxygen reduction reaction. JOURNAL OF POWER SOURCES 2005; 152:1-15. [DOI: 10.1016/j.jpowsour.2005.05.098] [Citation(s) in RCA: 344] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
|