Renewable WO3/Bi2O3 heterojunction for Photoelectrochemical and Visual Dual-mode Detection of Hydrogen Sulfide

The overexploitation and combustion of fossil fuels have caused serious hydrogen sulfide (H2S) pollution, which highlights the urgency for effective supervision. Herein, we report a renewable tungsten trioxide/bismuth oxide (WO3/Bi2O3) heterojunction for dual-mode photoelectrochemical (PEC) and visual determination of pernicious H2S. The spontaneous ion-exchange reaction induced partial transformation of Bi2O3 to Bi2S3 have made the “signal-on” PEC detection strategy available, while the obvious color difference from light cyan to khaki realizes the visual determination under high concentration. Correspondingly, the low limit of detection (LOD) of ca. 38 nM, the wide linear range for PEC (0.1–500 μM) and visual (50 μM - 5 mM) detection mode, and exclusively unique selectivity are achieved. Besides, the already-used sensor exhibits rich added value for highly efficient water splitting, and the detection process can be re-implemented multiple times by a facile regeneration treatment, paves a user-friendly approach for the controllable monitor of H2S.