High-performance non-enzymatic perovskite sensor for hydrogen peroxide and glucose electrochemical detection

Enzymeless detection of hydrogen peroxide (H₂O₂) and glucose offers a more reliable and accurate detection route given the absence of enzyme that is sensitive to temperature, pH, poisoning chemicals, and humidity. This can be realized using electrochemical sensor device which at present relies upon platinum, gold, or palladium-based nanostructured electrodes. Finding an alternative to such noble metal materials becomes crucial to facilitate large-scale applications of such device. Here, we reported that La_0.6Sr_0.4CoO_3-δ(LSC) perovskite oxide can provide comparable performance to these noble metal nanomaterials. LSC provides superior electrooxidation activities (to H₂O₂and glucose) over La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ(LSCF) and LaNi_0.6Co_0.4O₃(LNC) that translates to good H₂O₂or glucose detection performance. We proposed parallel pathways for H₂O₂and glucose oxidations on LSC perovskite, which proceeds via Co³⁺/Co⁴⁺redox couple and via oxygen vacancies formation. Additionally, reduced graphene oxide (RGO) can be added to optimize the detection performance. The best electrode, i.e., LSC + RGO/GCE provides sensitivity of 500 and 330 μA mM⁻¹cm⁻²for H₂O₂and glucose, respectively, and limit of detection of 0.05 and 0.063 μM for H₂O₂and glucose, respectively (at S/N = 3). Its respective linear ranges are 0.2–3350 μM and 2–3350 μM for H₂O₂and glucose, respectively.