Ultralow-platinum-loading nanocarbon hybrids for highly sensitive hydrogen peroxide detection

Detecting the trace amount of hydrogen peroxide (H2O2) is essential for various industrial and biological applications. Platinum (Pt) based electrochemical H2O2 sensors have good sensing performances. Considering the high cost of Pt, it is desirable to develop high-performance H2O2 sensors with low Pt mass loadings. Here, we use a cathodic polarization treatment method to deposit ultralow mass loading of Pt nanoparticles on a high surface area porous carbon hybrid comprised of reduced graphene oxide nanosheets (rGO) and carbon nanotubes (CNTs). Under multiple cyclic voltammetry (CV) cycles in electrolytes without Pt precursors, Pt can be leached from a Pt mesh anode, and then migrate through electrolyte and anchor on the rGO-CNT hybrid as nanoparticles with narrow size distribution. Varying the number of CV cycles can precisely control the Pt mass loadings. The optimized Pt/rGO-CNT hybrid obtained after 3000 CV cycles contains about 4.8 wt.% Pt nanoparticles with the size of around 3-6 nm. The morphological and physicochemical properties of the synthesized Pt/rGO-CNT hybrids were characterized to understand their synthesis-structure-sensitivity relationship. The Pt/rGO-CNT hybrid show superior H2O2 sensing performances with a low detection limit of 1 mu M, linear detection up to 15 mM, and high sensitivity of 2027 mu A/mM cm(2), which is the best among the recently reported Pt/carbon material based H2O2 sensors. It can also detect trace amount of H2O2 in milk, and juice samples below the permitted residual level in food packaging, demonstrating its excellent practical application potential in food processing.