Pt and Au bimetallic and monometallic nanostructured amperometric sensors for direct detection of hydrogen peroxide: Influences of bimetallic effect and silica support

•High performance metallic nanostructured H2O2 electrochemical sensors were developed.•Silica supported PtAu nanocatalyst has superior performance over the monometallic ones.•Non-supported Pt nanoparticle (NP) has better performance than that supported on silica.•The Pt NP performs the best, even better than the silica supported PtAu nanocatalyst.•Simpler wins. It is important to consider both bimetallic effects and nanocatalysts support in electrochemical sensor design. The non-enzyme direct electrochemical sensing of hydrogen peroxide (H2O2) by nanostructured electrodes of Pt- and Au-containing bimetallic or monometallic nanocatalysts including paramecium-like nanostructures of PtAu supported on silica nanorods, Pt and Au nanoparticles supported on silica nanorods, and the non-supported Pt and Au nanoparticles (NPs) is reported. The nanocatalysts modified electrodes were fabricated by simple self-assembling on 3-aminopropyl-trimethoxysilane (APTMS) modified glassy carbon. The cyclic voltammetric and amperometric results showed that PtAu supported on silica nanorods has superior performance over the corresponding monometallic counterparts, with a broad linear range from 5.0μM to 72000μM for H2O2, a detection limit of 2.6μM, a sensitivity of 46.7μAmM−1cm−2 at a lower working potential of −0.20V vs SCE, and has good stability and reproducibility. In addition, a systematic test showed that the non-supported Pt NPs sensor has a surprisingly high performance, even better than the paramecium-like nanostructure of PtAu supported on silica nanorods, where the existence of silica nanorod templates in the nanocatalysts retards the electrocatalytic reduction/oxidation of H2O2. Among the nanocatalysts tested in this work, the Pt NPs sensor showed fastest response within 3s, a broad linear response from 5μM to 58000μM, a detection limit of 4.2μM, and the highest sensitivity of 110.3μAmM−1cm−2 at the lowest working potential of −0.08V vs SCE. Notably, the performance of the Pt NPs sensor is also among the best Pt-containing monometallic or bimetallic nanostructured electrochemical sensors toward H2O2 reported so far. This work shows a simple method to fabricate H2O2 electrochemical sensors of high performance and indicates the importance of considering not only bimetallic effects but also the influences of the nanostructure of nanocatalysts on the electrocatalytic performance and electrochemical sensing property.