Influence of humidity on the surface properties of partially-reduced graphene oxide membranes
Jan Sebastian Dominic Rodriguez1,2*, Takuji Ohigashi3, Chi-Cheng Lee1, Meng-Hsuan Tsai4, Chueh-Chen Yang4,5, Chia-Hsin Wang4, Chi Chen6, Way-Faung Pong1, Hsiang-Chih Chiu7, Cheng-Hao Chuang1
1Department of Physics, Tamkang University, New Taipei City, Taiwan
2Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
3Institute for Molecular Science, Okazaki, Japan
4National Synchrotron Radiation Research Center, Hsinchu, Taiwan
5Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
6Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
7Department of Physics, National Taiwan Normal University, Taipei, Taiwan
* Presenter:Jan Sebastian Dominic Rodriguez, email:rodriguezjansdf@gmail.com
Previous efforts on studying the mechanism of water adsorption on graphene oxide (GO) has led to an understanding of the role of the oxygen functional groups in the process. However, the phenomena of water adsorption on the surface have yet to be unraveled. In this work, we investigated the behavior and chemical characteristics of GO surfaces when exposed to different humidity conditions. Under varying humidity, the overall work function decreased from 5.65 eV (5% RH) to 5.38 eV (85% RH). However, some areas of the surface potential maps followed different trends, with this phenomenon being induced by the variation in the concentration of oxygen functional groups, causing different areas to behave differently. Ambient-pressure XPS has shown an increase in adsorbed H2O (535.5 eV) with increased H2O pressure. Notable, however, is the observation of a reduced FWHM accompanying the increased peak intensity. X-ray absorption spectroscopy (XAS) during controlled humidity conditions indicated increased C-O-C signals at elevated RH, indicative of changes in the chemical composition of GO in the presence of adsorbed water. These findings deepen our understanding and offer insights into enhancing GO-based humidity sensors and dehumidification materials.


Keywords: carbon-based materials, surface science, water adsorption, atomic force microsc, ambient-pressure XPS