Highly efficient Ag doped δ-MnO₂ decorated graphene: Comparison and application in electrochemical detection of H₂O₂

Cytotoxic H₂O₂ is an inevitable part of our life, even during this contemporary pandemic COVID-19. Personal protective equipment of the front line fighter against coronavirus could be sterilized easily by H₂O₂ for reuse. In this study, Ag doped δ-MnO₂ nanorods supported graphene nanocomposite (denoted as Ag@δ-MnO₂/G) was synthesized as a nonenzymatic electrochemical sensor for the sensitive detection of H₂O₂. The ternary nanocomposite has overcome the poor electrical conductivity of δ-MnO₂ and also the severe aggregation of Ag NPs. Furthermore, δ-MnO₂/G provided a rougher surface and large numbers of functional groups for doping more numbers of Ag atoms, which effectively modulate the electronic properties of the nanocomposite. As a result, electroactive surface area and electrical conductivity of Ag@δ-MnO₂/G increased remarkably as well as excellent catalytic activity observed towards H₂O₂ reduction. The modified glassy carbon electrode exhibited fast amperometric response time (<2 s) in H₂O₂ determination. The limit of detection was calculated as 68 nM in the broad linear range (0.005-90.64 mM) with high sensitivity of 104.43 µA mM^-1 cm^-2. No significant interference, long-term stability, excellent reproducibility, satisfactory repeatability, practical applicability towards food samples and wastewater proved the efficiency of the proposed sensor.