fig4

Figure 4. (A) SEM image of the TiO2 nanotube array formed by anodizing titanium fibers. (B) Membrane electrode assembly used in vapor-fed PEC water splitting in a humidified argon atmosphere (3 vol% H2O), utilizing TiO2 nanotube array photoanodes and Pt-carbon cathodes. The effect of PFSA ionomer coating number on their photocurrent response and IPCE at an applied voltage of 1.2 V vs. cathode (wavelength: 365 nm, irradiance: 56 mW cm-2, irradiation area: 1 cm2) has also been included. Reproduced with permission from ref.[26], Copyright 2018 Wiley.