Investigating unexpected magnetism of mesoporous silica-supported Pd and PdO nanoparticles

Handle URI:
http://hdl.handle.net/10754/564005
Title:
Investigating unexpected magnetism of mesoporous silica-supported Pd and PdO nanoparticles
Authors:
Song, Hyon Min; Zink, Jeffrey I.; Khashab, Niveen M. ( 0000-0003-2728-0666 )
Abstract:
The synthesis and magnetic behavior of matrix-supported Pd and PdO nanoparticles (NPs) are described. Mesoporous silica with hexagonal columnal packing is selected as a template, and the impregnation method with thermal annealing is used to obtain supported Pd and PdO NPs. The heating rate and the annealing conditions determine the particle size and the phase of the NPs, with a fast heating rate of 30 °C/min producing the largest supported Pd NPs. Unusual magnetic behaviors are observed. (1) Contrary to the general belief that smaller Pd NPs or cluster size particles have higher magnetization, matrix-supported Pd NPs in this study maintain the highest magnetization with room temperature ferromagnetism when the size is the largest. (2) Twin boundaries along with stacking faults are more pronounced in these large Pd NPs and are believed to be the reason for this high magnetization. Similarly, supported PdO NPs were prepared under air conditions with different heating rates. Their phase is tetragonal (P42/mmc) with cell parameters of a = 3.050 Å and c = 5.344 Å, which are slightly larger than in the bulk phase (a = 3.03 Å, c = 5.33 Å). Faster heating rate of 30 °C/min also produces larger particles and larger magnetic hysteresis loop, although magnetization is smaller and few twin boundaries are observed compared to the supported metallic Pd NPs.
KAUST Department:
Advanced Membranes and Porous Materials Research Center; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; Smart Hybrid Materials (SHMs) lab
Publisher:
American Chemical Society (ACS)
Journal:
Chemistry of Materials
Issue Date:
13-Jan-2015
DOI:
10.1021/cm502448p
Type:
Article
ISSN:
08974756
Sponsors:
We gratefully acknowledge support from Dong-A University, King Abdullah University of Science and Technology (KAUST), and NSF Grant DBI-1266377. We also acknowledge Bei Zhang in the Nanofabrication core lab at KAUST for his help with the magnetic measurements. The work at UCLA also leveraged the support provided by the National Science Foundation and the Environmental Protection Agency under Cooperative Agreement Number, DBI 0830117.
Appears in Collections:
Articles; Advanced Membranes and Porous Materials Research Center; Physical Sciences and Engineering (PSE) Division; Controlled Release and Delivery Laboratory; Chemical Science Program

Full metadata record

DC FieldValue Language
dc.contributor.authorSong, Hyon Minen
dc.contributor.authorZink, Jeffrey I.en
dc.contributor.authorKhashab, Niveen M.en
dc.date.accessioned2015-08-03T12:22:45Zen
dc.date.available2015-08-03T12:22:45Zen
dc.date.issued2015-01-13en
dc.identifier.issn08974756en
dc.identifier.doi10.1021/cm502448pen
dc.identifier.urihttp://hdl.handle.net/10754/564005en
dc.description.abstractThe synthesis and magnetic behavior of matrix-supported Pd and PdO nanoparticles (NPs) are described. Mesoporous silica with hexagonal columnal packing is selected as a template, and the impregnation method with thermal annealing is used to obtain supported Pd and PdO NPs. The heating rate and the annealing conditions determine the particle size and the phase of the NPs, with a fast heating rate of 30 °C/min producing the largest supported Pd NPs. Unusual magnetic behaviors are observed. (1) Contrary to the general belief that smaller Pd NPs or cluster size particles have higher magnetization, matrix-supported Pd NPs in this study maintain the highest magnetization with room temperature ferromagnetism when the size is the largest. (2) Twin boundaries along with stacking faults are more pronounced in these large Pd NPs and are believed to be the reason for this high magnetization. Similarly, supported PdO NPs were prepared under air conditions with different heating rates. Their phase is tetragonal (P42/mmc) with cell parameters of a = 3.050 Å and c = 5.344 Å, which are slightly larger than in the bulk phase (a = 3.03 Å, c = 5.33 Å). Faster heating rate of 30 °C/min also produces larger particles and larger magnetic hysteresis loop, although magnetization is smaller and few twin boundaries are observed compared to the supported metallic Pd NPs.en
dc.description.sponsorshipWe gratefully acknowledge support from Dong-A University, King Abdullah University of Science and Technology (KAUST), and NSF Grant DBI-1266377. We also acknowledge Bei Zhang in the Nanofabrication core lab at KAUST for his help with the magnetic measurements. The work at UCLA also leveraged the support provided by the National Science Foundation and the Environmental Protection Agency under Cooperative Agreement Number, DBI 0830117.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleInvestigating unexpected magnetism of mesoporous silica-supported Pd and PdO nanoparticlesen
dc.typeArticleen
dc.contributor.departmentAdvanced Membranes and Porous Materials Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentSmart Hybrid Materials (SHMs) laben
dc.identifier.journalChemistry of Materialsen
dc.contributor.institutionDepartment of Chemistry, University of CaliforniaLos Angeles, CA, United Statesen
dc.contributor.institutionDepartment of Chemistry, Dong-A UniversityBusan, South Koreaen
kaust.authorKhashab, Niveen M.en
kaust.authorSong, Hyon Minen
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