Understanding the Nucleation, Growth, and Immobilization of Metal Clusters Using First Principles Theoretical Calculations and Mass Spectrometry
EMSL Project ID
49272
Abstract
The properties of clusters vary substantially with the addition or removal of single atoms. This size-dependent behavior enables tuning of the activity and selectivity of cluster-based catalysts with atomic-level precision. To facilitate the widespread application of clusters as catalysts scalable solution-phase synthesis techniques are needed which involve the use of ligands to arrest cluster growth at a certain size and prevent agglomeration. While the final products of batch synthesis have been well characterized, little is known about the intermediates formed during the early stages of synthesis and throughout post reduction etching. We will address this critical shortcoming by employing a complementary theoretical and experimental approach. Theoretical calculations will be used to determine how the charge donating capacity of the phosphine centers as well as steric factors in the ligands influence gold cluster size and stability. A temperature-controlled flow reactor will be used to prepare steady-state distributions of phosphine-ligated gold clusters. The reactor will be coupled with electrospray ionization mass spectrometry to enable insight into how temperature, concentration, and reaction time influence the distribution of clusters. Optimized reactor conditions will be employed to prepare stable ion currents of cationic gold clusters for characterization using surface-induced-dissociation in a Fourier transform ion cyclotron resonance mass spectrometer. Employing this approach, the size-dependent stability and dissociation pathways of phosphine-ligated gold clusters will be examined and compared with the results of theoretical calculations. Cutting-edge modeling capabilities and characterization techniques available at EMSL will be employed to investigate the properties of these cluster intermediates. The electronic structure and reactivity of the supported clusters will be examined using theoretical calculations. The proposed research is directly relevant to the "Energy Materials and Processes" science theme. Specifically, we develop new theoretical methods and instrumentation to establish a fundamental understanding of the scalable synthesis and self-assembly of cluster-based materials of interest to DOE's energy mission.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2016-10-01
End Date
2018-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Hewitt M.A., H. Hernandez, and G.E. Johnson. 2020. "Light Exposure Promotes Degradation of Intermediates and Growth of Phosphine-Ligated Gold Clusters." Journal of Physical Chemistry C 124, no. 5:3396-3402. PNNL-SA-149386. doi:10.1021/acs.jpcc.9b10920
Johnson GE, and J Laskin. 2016. "Understanding Ligand Effects in Gold Clusters using Mass Spectrometry." Analyst 141(12):3573-3589. doi:10.1039/c6an00263c
Laskin J., G.E. Johnson, J. Warneke, and V. Prabhakaran. 2018. "From Isolated Ions to Multilayer Functional Materials Using Ion Soft-Landing." Angewandte Chemie 57, no. 50:16270-16284. PNNL-SA-130953. doi:10.1002/anie.201712296
Ligare MR, GE Johnson, and J Laskin. 2017. "Observing the Real Time Formation of Phosphine-Ligated Gold Clusters by Electrospray Ionization Mass Spectrometry." Physical Chemistry Chemical Physics. PCCP 19(26):17187-17198. doi:10.1039/c7cp01402c
Ligare M.R., J.U. Reveles Ramirez, N. Govind, G.E. Johnson, and J. Laskin. 2019. "Influence of Inter-Ligand Interactions and Core Charge Distribution on Gold Cluster Stability: Enthalpy vs Entropy." The Journal of Physical Chemistry C 123, no. 40:24899-24911. PNNL-SA-136687. doi:10.1021/acs.jpcc.9b06597
Parrish K.A., M.E. King, M.R. Ligare, G.E. Johnson, and H. Hernandez. 2019. "Role of Sterics in Phosphine-Ligated Gold Clusters." Physical Chemistry Chemical Physics. PCCP 21, no. 4:1689-1699. PNNL-SA-134177. doi:10.1039/C8CP04961K
Warneke J., M.E. McBriarty, S.L. Riechers, S. China, M.H. Engelhard, E. Apra, and R.P. Young, et al. 2018. "Self-organizing layers from complex molecular anions." Nature Communications 9, no. 1:1889. PNNL-SA-128240. doi:10.1038/s41467-018-04228-2