Exploring and tuning microscale reactions and multiphase flow in water splitting and hydrogen production

Hydrogen is a key zero-emission energy storage medium in energy industry of the world. The electrolysis of water with proton exchange membrane electrolyzer cells (PEMECs) has been considered as a promising technology for producing hydrogen and oxygen. The understanding of the electrochemical reactions and two-phase flow phenomena occur in PEMECs is a very important part in promoting energy efficiency of both engineering and sciences. Effective two-phase flow transport is key factor for PEMECs to achieve high performance, since the accumulation of bubble blocks the active areas, and leads to mass transport losses. The objective of the research is to investigate the oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and temperature distribution variance, in order to better understand the mechanism of electrochemical reactions and bubble dynamics, and how their impact on the cell performance. The main task of this thesis includes: (a) in-situ visualize and investigate the OER for better understanding the bubble growth process; (b) in-situ and ex-situ investigate the impact of wettability on the bubble dynamics and cell performance in a PEMEC with Ti thin film LGDL; (c) in-situ visualize and investigate the OER and HER in PEMECs for better understanding the bubble detachment process. (d) in-situ visualize and investigate the temperature variance and hydrogen bubble dynamics for better understanding the mechanism of HER; (e) in-situ visualize and investigate the bubble dynamics and two-phase flow in PEMECs with Ti felt LGDL.