Enhancement of mass transport behavior by controlling the surface structure of the porous transport layer for polymer electrolyte membrane water electrolysis

Abstract

Chemical etching is an effective method, frequently used in the modification of the surface and structure of the metals while these two properties are important factors that affect the performance of porous transport layers (PTLs) in polymer electrolyte membrane water electrolysis (PEMWE). In this study, the commercial titanium porous transport layers (Ti-PTLs) are modified with 6 M H₂SO₄ acid for 20 min at various temperatures (40 ℃, 60 ℃, 80 ℃, and 90 ℃). The surface morphology, structure, and electrochemical properties of PTLs are analyzed by scanning electron microscope (SEM), contact angle measurement, porosimeter, polarization, and electrochemical impedance spectroscopy (EIS). The physical and chemical analysis reveals that surface modified PTLs prepared at 80 ℃ and 90 ℃ exhibit a significant increase in porosity due to changes in structure, shape, and interface properties. Consequently, mass transport resistance is significantly reduced. The results indicate that higher temperatures during acid etching lead to increased porosity and hydrophilicity of the PTLs, directly affecting the mass transport phenomenon in PEMWEs.