Photoelectrocatalytic generation of H2 and S from toxic H2S by using a novel BiOI/WO3 nanoflake array photoanode

Abstract

In this paper, a photoelectrocatalytic (PEC) recovery of toxic H₂S into H₂ and S system was proposed using a novel bismuth oxyiodide (BiOI)/ tungsten trioxide (WO₃) nano-flake arrays (NFA) photoanode. The BiOI/WO₃ NFA with a vertically aligned nanostructure were uniformly prepared on the conductive substrate via transformation of tungstate following an impregnating hydroxylation of BiI₃. Compared to pure WO₃ NFA, the BiOI/WO₃ NFA promotes a significant increase of photocurrent by 200%. Owing to the excellent stability and photoactivity of the BiOI/WO₃ NFA photoanode and \({{\rm{I}}^ - }{\rm{/I}}_3^ - \) catalytic system, the PEC system toward splitting of H₂S totally converted S²⁻ into S without any polysulfide (\({\rm{S}}_x^{n - }\)) under solar-light irradiation. Moreover, H₂ was simultaneously generated at a rate of about 0.867 mL/(h ·cm). The proposed PEC H₂S splitting system provides an efficient and sustainable route to recover H₂ and S.