Cobalt-based layered double hydroxide nanosheet-supported AuNPs for high performance electrochemical H2O2 detection

Abstract

Enzyme-free electrochemical sensors with both high sensitivity and selectivity for H2O2 is highly desirable for biological science. During the electrochemical reduction of H2O2, the breakage of the O-O bond and subsequent stabilization of OH on the electrode are key to the performance of the electrochemical sensors. Noble metal nanoparticles could efficiently stabilize the above intermediate, but the stability of the naked nanoparticles was not satisfactory. Carbon-based supported materials are thus proposed, but lack efficient active sites for H2O2 reduction. Herein, cobalt-based layered double hydroxide-supported gold nanoparticles (AuNPs/Co-LDH) nanocomposite were fabricated as the electrode material for high-performance electrochemical H2O2 reduction in neutral media. Due to the abundant redox sites (Co2+/Co3+) and large surface area, AuNPs were formed in situ on Co-LDH with good dispersion and stability. Meanwhile, the redox sites of Co-LDH could also aid the electrochemical H2O2 reduction. A sensitivity of 406.61 μA mM−1 cm−2 and a detection limit of 0.19 μM were achieved, which outperformed most of reported nanomaterials. The above excellent electrochemical properties endow the follower-like AuNPs/Co-LDH as promising alternative to enzymes in the biological field.