Photoanode with Enhanced Performance Achieved by Coating BiVO₄ onto ZnO-Templated Sb-Doped SnO₂ Nanotube Scaffold

The performance of BiVO₄ photoanodes, especially under front-side illumination, is limited by the modest charge transport properties of BiVO₄. Core/shell nanostructures consisting of BiVO₄ coated onto a conductive scaffold are a promising route to improving the performance of BiVO₄-based photoanodes. Here, we investigate photoanodes composed of thin and uniform layers of BiVO₄ particles coated onto Sb-doped SnO₂ (Sb:SnO₂) nanotube arrays that were synthesized using a sacrificial ZnO template with controllable length and packing density. We demonstrate a new record for the product of light absorption and charge separation efficiencies (η_abs × η_sep) of ∼57.3 and 58.5% under front- and back-side illumination, respectively, at 0.6 V_RHE. Moreover, both of these high η_abs × η_sep efficiencies are achieved without any extra treatment or intentional doping in BiVO_4. These results indicate that integration of Sb:SnO₂ nanotube cores with other successful strategies such as doping and hydrogen treatment can increase the performance of BiVO₄ and related semiconductors closer to their theoretical potential.