Enhancing performance of anion exchange membrane electrolyzer through modification of carbon paper liquid-gas diffusion layer.

In this study, the microstructure of carbon fiber paper is modified through H 3 PO 4 etching to enhance the electrolyzer performance. The effects of different H 3 PO 4 concentrations and different soaking times on the hydrogen evolution reaction are firstly investigated. The electrochemical test results show that the best performance of etched electrodes is achieved at a H 3 PO 4 concentration of 1 M and a soaking time of 12 h, with a significant reduction in charge transfer resistance and overpotential. Subsequently, to explore the change mechanism in electrochemical properties, the microstructure of the carbon paper is investigated using Scanning Electron Microscope (SEM) and Mercury Intrusion Porosimetry (MIP) tests, which show uniformly distributed micropores appear on the surface of the carbon fibers after etching, and the porosity increases from 0.74 to 0.8. Brunauer-Emmett-Teller (BET) tests show that the specific surface area of the carbon paper increases from 0.72 m2/g to 4.06 m2/g, which effectively increases the interfacial contact area between the catalyst layer and the liquid gas diffusion layer. Furthermore, a 3D multi-physics model is established to further elucidate the impact mechanism of changes in porosity, conductivity, and active specific surface area on the performance of anion exchange membrane electrolyzer, with changes in active specific surface area having the greatest effect. • Microporous structure of the carbon paper LGDL is modified by etching. • The etching method effectively improves the performance of AEMEL. • The increase in specific surface area and porosity greatly reduces the resistance. • Numerical modeling to analyze the impact of microscopic parameters on AEMEL. • LGDL with high specific surface area has a positive effect on AEMEL's development. [ABSTRACT FROM AUTHOR]