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Updated: Jul 27, 2025
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Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing
Published on: June 9, 2023
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Influence of subatmospheric pressure on bubble evolution on the TiO
Xinyi Luo1, Qiang Xu1, Tengfei Nie1
1State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, Shaanxi, 710049, P. R. China. qiang.xu@mail.xjtu.edu.cn.
Physical Chemistry Chemical Physics : PCCP
|June 6, 2023
Summary
Decreasing pressure in photoelectrochemical water splitting reduces photocurrent but increases bubble size. Concentration Marangoni force, not thermal, drives bubble departure under lower pressures.
Area of Science:
- Materials Science
- Electrochemistry
- Chemical Engineering
Background:
- Bubble nucleation and growth on photoelectrode surfaces impede photoelectrochemical water splitting efficiency.
- Understanding bubble dynamics is crucial for optimizing water splitting performance.
Purpose of the Study:
- To investigate oxygen bubble behavior on TiO2 photoelectrodes.
- To correlate bubble geometric parameters with photocurrent fluctuations under varying pressures and laser powers.
- To analyze the forces governing bubble departure.
Main Methods:
- In situ observation using an electrochemical workstation and high-speed microscopy.
- Systematic variation of pressure and laser power.
- Construction of a force balance model for bubble departure.
Main Results:
- Photocurrent decreases and bubble departure diameter increases with reduced pressure.
- Bubble nucleation and growth stages shorten at lower pressures.
- Concentration Marangoni force becomes dominant in bubble departure under subatmospheric pressures.
Conclusions:
- Concentration Marangoni force is the primary driver for bubble departure diameter under subatmospheric conditions.
- Optimizing photoelectrode performance requires managing bubble dynamics and forces.
- Gas mass production rate peaks near 80 kPa.
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