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

Enzymeless detection of hydrogen peroxide (H 2 O 2 ) 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 0.6 Sr 0.4 CoO 3-δ (LSC) perovskite oxide can provide comparable performance to these noble metal nanomaterials. LSC provides superior electrooxidation activities (to H 2 O 2 and glucose) over La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) and LaNi 0.6 Co 0.4 O 3 (LNC) that translates to good H 2 O 2 or glucose detection performance. We proposed parallel pathways for H 2 O 2 and glucose oxidations on LSC perovskite, which proceeds via Co 3+ /Co 4+ 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 −1   cm −2 for H 2 O 2 and glucose, respectively, and limit of detection of 0.05 and 0.063   μM for H 2 O 2 and glucose, respectively (at S/N   =   3). Its respective linear ranges are 0.2–3350   μM and 2–3350   μM for H 2 O 2 and glucose, respectively.