EXPLORING SOLID-LIQUID INTERFACIAL CHEMISTRY DURING CATALYST SYNTHESIS Christopher T. Williams, John R. Monnier, John R. Regalbuto USC Center for Rational.

EXPLORING SOLID-LIQUID INTERFACIAL CHEMISTRY DURING

CATALYST SYNTHESIS

Christopher T. Williams, John R. Monnier, John R. Regalbuto

USC

Center for Rational Catalyst SynthesisPlanning Grant Workshop

University of South Carolina, Columbia, SCJune 16, 2014

Exploring Solid-Liquid Interfacial Chemistry During Catalyst Synthesis

Industrial Relevance: Precise control of synthesis

Technical Information: in-situ surface vibrational (FTIR, Raman) spectroscopy; optimization of catalyst synthesis process.

Research Team: Williams, Monnier, Regalbuto (USC)Overview: Probe surface chemistry during SEA and ED processes to facilitate optimization of bimetallic catalyst synthesis

17751875197520752175

Wavenumber (cm-1)

Ab

so

rba

nc

e

1814

2052

e

d

c

b

a

0.0025 a.u.

h

Industrial RelevanceMinimize Metal Usage in

Bimetallic Catalysts

Producing Bimetallic Catalysts with Small

Particle Sizes

Goals of the Proposal

Use Attenuated Total Reflection Infrared (ATR-IR) and Raman spectroscopies to explore surface chemistry during ED and SEA synthesis of bimetallic catalysts

Correlate surface speciation with ED and SEA synthetic parameters and resulting catalyst properties

Develop strategies to overcome limitations and enhance performance of the approaches

Proposal Hypotheses

Adsorption of chemical species from solution plays key roles in ED stabilizers; reducing agents (e.g., formaldehyde, DMAB, NaBH4), also in

their oxidized forms and their fragments, e.g., CO; varying extents/strengths of adsorption on various metals helps to determine

the selectivity of autocatalytic vs. catalytic deposition adsorbed species can result in sintering of small nanoparticles due to

enhanced mobility of atoms (e.g., metal complexes)

The stability of surface oxides during sequential SEA methods is a key determining factor in its success adsorption of precursors onto support and first metal oxide can result in

alteration of the oxide formation of mixed oxides during the activation treatment will effect

eventual properties of reduced bimetallic particles

Correlation of surface speciation (measured with spectroscopy) and solution-phase parameters (measured during synthesis) can be coupled to generate predictive models

Research Methods/ TechniquesIn-Situ ATR-IR and Raman of Support/Catalyst Films in the Liquid

Phase

In-Situ Raman During Gas-Phase Activation of Catalysts

Outcomes/ Deliverables – Year 1

Mn-Rh/SiO2 synthesis by SEA explored by Raman Liquid-phase adsorption of MnO4

- species onto supported Rh2O3 under different solution-phase conditions

Gas--phase calcination/reduction of SiO2-supported MnO4-/MnO4

-/Rh2O3 particles

Correlation of surface speciation with resulting bimetallic particle structure

Ag-Pt/X (X=SiO2,Al2O3) synthesis by ED explored by ATR-IR Adsorption/activation of reducing agents - formaldehyde, hydrazine,

dimethylamine borane - on Pt catalysts, bare supports, and Pt metal ED of AgNO3 onto Pt catalysts and Pt metal under different conditions Influence of adsorbed CO on the speciation during ED process Correlation of surface speciation with deposition limits and sintering observed

in batch and/or continuous ED experiments

Longer Term Plans (beyond first year) Extension to other SEA/ED synthetic systems as suggested by EAB Development of predictive models based on surface chemistry insight

Impact Improved understanding of surface chemical factors that may

hinder implementation of SEA and ED in industry Enhanced catalyst properties at reduced cost?

Establishment of in-situ solid-liquid interface techniques that can address needs of EAB members ATR-IR can be applied to a broad range of liquid-phase adsorption and

reaction processes relevant to catalytic materials synthesis

1 year @ $60,000

$60,000/yr thereafter, expanding to other systems as desired

Duration of Project and Proposed Budget