Photoelectrochemical Behavior of WO₃ in an Aqueous Methanesulfonic Acid Electrolyte

Abstract

N-type semiconducting WO 3 is widely investigated as a photoanode operating in water and seawater splitting devices. Because of the propensity of WO 3 to favor photo-oxidation of acidic electrolyte anions and, in parallel, the formation on the electrode surface of the peroxo species, the choice of the appropriate electrolyte to allow stable operation of the photoanode is of critical importance. Our results from structural and photoelectrochemical tests performed using mesoporous WO 3 photoanodes exposed to 80 h long photoelectrolysis in a 1 M aq. methanesulfonic acid supporting electrolyte demonstrate the photostability of both the WO 3 photomaterial and the CH 3 SO 3 H electrolyte. The reasons for the stability of aqueous solutions of CH 3 SO 3 H are discussed on the basis of earlier literature reports.

The route for commercial photoelectrochemical water splitting: a review of large-area devices and key upscaling challenges

“…BiVO 4 ,79,98,99 WO 3 ,75,100,101 Cu 2 O35,102 and Ta 3 N 584,86,103 PEs based on active area, stability and current density generated at a reference potential of 1.23 V (except 0 V for Cu 2 O); normalization considered equal 33.3(3)% contribution for each criterion, delivering a total score out of 100, and considering the following targets: (i) active area of 100 cm 2 ; (ii) 2920 h of stable performance (8 h over 365 days; max. 10% current loss); and (iii) current density of 10 mA cm À2 .…”