authors.library.caltech.edu · web viewto this solution 25.5 g (87.1 mmol) of edta (alfa aesar,...

A Gallium Phosphate Piezo-Microbalance System for High-Temperature Mass Relaxation Studies of Metal

OxidesPhilipp Simonsa,b,c, Ho-Il Jia,d, Timothy C. Davenporta,d, and Sossina M. Haile*a,d,e

a Materials Science, California Institute of Technology, Pasadena, CA 91125, USAb Department of Information Technology and Electrical Engineering, ETH Zurich, 8092 Zurich, Switzerland

c Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerlandd Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA

e Applied Physics, Northwestern University, Evanston, IL 60208, USA

Supplementary Information

The 10PCO powder was prepared by dissolving 22.7 g (52.3 mmol) of Ce(NO3)3·6H2O (Alfa

Aesar, 99.5%) and 2.53 g (5.81 mmol) of Pr(NO3)3·6H2O (Alfa Aesar, 99.99%) in 250 mL of

water. To this solution 25.5 g (87.1 mmol) of EDTA (Alfa Aesar, 99%) and 16.7 g (87.1 mmol)

of citric acid (Alfa Aesar, 99.5+%) was added. Subsequently, 60 mL of concentrated NH4OH

(Aldrich) was slowly added to form a homogeneous green solution which was stirred for 24

hr at 65 °C. The resulting gel was heated at 5 °C min-1 to 170 °C with a dwell for 5 hr, forming

a black foam that was ground into a powder. The powder was then heated at 5 °C min-1 to

350 °C with a dwell for 15 hr, followed by 5 °C min-1 to 950 °C with a dwell for 10 hr to form

10PCO as a red powder.

Figure S1. Scanning phase contrast images of 10PCO films deposited on (left) Ti-bearing Pt

electrodes and (right) Ti free electrodes.

20 30 40 50 60 70

10PCO (Ti-free)

10PCO (Ti-bearing)

(400)(222)

(311)

(220)(200)

Inten

sity /

a.u.

2 / o

(111)

XRD holder

Figure S2: XRD patterns of 10PCO films with Ti-free (red line) and Ti-bearing (green line)

electrodes after mass relaxation characterization. The XRD pattern of the XRD holder is

displayed as a black line for reference.

0 4 8 12 16

5458500

5459000

5459500

5460000Fr

eque

ncy

/ Hz

Time / h

Frequency / Hz Exponential Fit pO2 / atm

1E-5

1E-4

0,001

0,01

0,1

pO2 /

atm

Figure S3: Long term frequency profile of the piezocrystal with Ti adhesion layer (black) as

well as the oxygen partial pressure (red) as a function of time throughout the entire

measurement campaign. An exponential fit is performed to the base line drift, fitted through

all measurements at which ultra-high purity argon is supplied through the chamber. Fitted

function: f (t )=5.458900 ⋅106Hz+862.616Hz ⋅exp (−2.707 ⋅10−5t ). Temperature: T = 700°C.

Figure S4. Long term frequency profile of the piezocrystal without Ti adhesion layer (black)

as well as the oxygen partial pressure (red) as a function of time, throughout the entire

measurement campaign.