Electroactive Cu₂O nanocubes engineered electrochemical sensor for H₂S detection

An electrochemical sensor was proposed for the detection of hydrogen sulfide (H₂S) at room temperature, by using electroactive Cu₂O nanocubes (NCs) as an electrochemical beacon. Electroactive Cu₂O NCs were synthesized on the surface of reduced graphene oxide (rGO)/Fe₃O₄ nanosheets (NSs) due to the good electronic conductivity and well-responded magnetic responses. The fabricated rGO/Fe₃O₄/Cu₂O NSs not only showed electrochemical oxidization peak at -0.1 V from Cu₂O NCs, and could be served as sensitive electrochemical beacon for the simple modification on magnetic electrodes in the applications. The unique redox reaction between Cu₂O NCs and H₂S enabled the transformation of Cu₂O NCs to Cu₉S₈ NCs, resulting in decreased electroxidation responses at -0.1 V. The constructed electrochemical platform had a limit of detection (LOD) of 230 pM and a detection range of 500 pM-100 μM. The simple and cheap electrochemical sensor developed in this paper showed potential application for H₂S detection.