Seed layer formation determines photocurrent response of hydrothermally-grown WO₃ photoanodes

Abstract

Due to its superior electrical properties and band gap suitable to absorb visible light, WO3 is an exceptional photoanode material for photoelectrochemical water splitting. The hydrothermal growth of WO3 photoelectrodes...

On the structural evolution of nanoporous optically transparent CuO photocathodes upon calcination for photoelectrochemical applications

“…4,5,8–11 Especially, earth-abundant metal oxides are well studied photoabsorber materials for PEC water splitting 12,13 due to their natural abundance, good processability, and improved stability in oxidative environments (without the necessity of protection layers), especially when compared to sulfides and nitrides – all factors leading to substantially lower production costs. 12,14 However, binary metal oxides including α-Fe 2 O 3 , 15,16 WO 3 , 17,18 TiO 2 , 19,20 and ZnO 21 and ternary metal oxides, such as BiVO 4 22,23 and CuBi 2 O 4 24,25 are still not meeting the required demands for commercialization due to insufficient energy conversion efficiencies. This is partly a result of photovoltage losses resulting from polaron formation effects in metal oxides.…”

Earth-Abundant Metal Oxides for Monolithic Tandem Photoelectrochemical Water Splitting Devices: Current Trends and Perspectives

“…Photovoltages of various photoanodes made up of BiVO 4 , − Fe 2 O 3 , − Cu 2 O, − and WO 3 − reported from the previous studies.…”

“…Consequently, BiVO 4 and other metal oxides exhibit considerably lower performances in comparison to what is anticipated from the Schottky-Queisser limit. Figure shows the performances of metal oxide photoelectrodes in terms of photovoltage reported from the previous studies on BiVO 4 , − Fe 2 O 3 , − Cu 2 O, − and WO 3 . − The photovoltages are estimated from the difference between the onset potentials where PEC devices begin to generate the current density from a targeted electrochemical reaction (HER for photocathode and OER for photoanode) and redox potential of the electrochemical reactions (0 V vs RHE for HER and 1.23 V vs RHE for OER). Although the performances of the metal oxide photoanode have significantly improved, there are still large discrepancies between the theoretical limit.…”