Sensitive electrochemical sensor for nitrite ions based on rose-like AuNPs/MoS2/graphene composite

Nitrite ions (NO2−) have been widely used in the food and drink industry as preservatives. However, the NO2− discharged into the environment is harmful to the ecosystem and human health. Due to its potential toxicity, selective and sensitive detection of nitrite is important. In this work, a rose-like Au nanoparticles/MoS2 nanoflower/graphene (AuNPs/MoS2/GN) composite was fabricated using a one-pot hydrothermal method without the addition of any extra reductant for use in nitrite detection. Graphene acts as an efficient matrix for the growth of MoS2 nanoflower (NF), and the edges of the MoS2 NF subsequently load AuNPs. The obtained AuNPs/MoS2/GN composite exhibits excellent electrooxidative activity toward nitrite ions, which is attributable to its large specific surface area, good conductivity, and the synergistic catalysis of each component. Accordingly, we propose a rapid, sensitive, and cost-effective electrochemical method for nitrite detection, which achieved a linear dynamic range of 5.0 μM to 5.0 mM with a detection limit of 1.0 μM. The present work provides not only a general one-pot synthesis method for a variety of noble–transition metal dichalcogenides nanohybrids, but also an example of the fabrication of an electrochemical nitrite sensor using a nanohybrid as an enhanced material, an approach that can easily be extended to other sensors. •One-pot hydrothermal synthesis of rose-like AuNPs/MoS2/GN without addition of extra reductant.•MoS2 nanoflower showed large surface area and maximize the exposure of active sites.•The edges of MoS2 sheets with high density of energetic defects acted as substrate for AuNPs to grow.•Propose a general way for one-pot synthesis of noble–transition metal sulfide nanohybrids.•The constructed sensor with AuNPs/MoS2/GN as an enhanced material can be extended to other sensors.