CuS nanoparticles (NPs) and CuS NPs/alginate nanocomposite films are prepared using a novel method based on the coordinated electrodeposition of alginate. This method exquisitely utilizes the coordination of alginate with Cu 2+ ions to carry out the electrodeposition, and alginate as the stabilizer for CuS NPs and the major ingredient in the nanocomposite film. Thus, the method has many advantages such as facile operation, green route, mild conditions, and convenient post-treatment. After the electrodeposition, a smooth and homogeneous film has been electrodeposited on the anodic electrode. Transmission electron microscopy observation reveals that there are nanoparticles (the average size of 6.0 nm) in the electrodeposited film. The results from spectral analysis further confirm the existence of CuS NPs. The CuS NPs/alginate nanocomposite film modified electrode can be directly constructed by taking advantage of the electrodeposition, which shows the electrochemical detection capability towards H 2 O 2 and hydroquinone. The CuS NPs/alginate nanocomposite film also possesses the colorimetric detection capability toward H 2 O 2 and dopamine. Therefore, this study offers a green and convenient method for fabricating CuS NPs and nanocomposite films, which is promising for applications in functional nanocomposites and detection fields.

Here, a facile and green approach based on the coordinated electrodeposition of carboxymethyl cellulose (CMC) is developed to fabricate silver nanoclusters (AgNCs) and AgNCs/CMC nanocomposite films. In the approach, CMC not only serves as the electrodeposition polysaccharide, but also acts as the stabilizing agent and reducing agent for the synthesis of AgNCs, as well as the major component in the resulting AgNCs/CMC nanocomposite film. After the electrodeposition and incubation, a homogeneous and smooth film is generated on the anodic electrode, which exhibits a clear yellow florescence. Transmission electron microscopy observation shows that there are nanoparticles with the average size of 1.7 nm in the nanocomposite film. X‐ray photoelectron spectroscopy, UV–vis absorption spectroscopy, and fluorescence spectroscopy both confirm that there are AgNCs in the nanocomposite film. The AgNCs/CMC nanocomposite film shows the capability for fluorescence detection by using the fluorescence quenching features of AgNCs. Moreover, the AgNCs/CMC‐modified electrode can be conveniently and directly produced, which presents potential applications for electrochemical biosensors. Thus, this study provides a novel approach for the green synthesis of AgNCs and direct fabrication of the AgNCs/CMC nanocomposite film, which can be promisingly applied for constructing functional nanocomposites and advanced biodevices.