Construction of hollow core-shell CuS@NiMn-LDH heterostructured nanoboxes as efficient electrocatalysts for formaldehyde sensing

As a carcinogen hazardous to the environment and human health, formaldehyde (HCHO) has attracted an increasing interest in the field of electrochemical detection. In this work, NiMn-LDH nanosheets are synthesized onto CuS nanoboxes by a multi-step template engagement strategy combined with solvothermal method to form a unique hollow core-shell heterostructured nanoboxes (CuS@NiMn-LDH HNBs). The unique nanosheet wrapped hollow nanobox shortens the electron/ion diffusion path and provides abundant active sites for the oxidation of HCHO. As an efficient electrocatalyst, the CuS@NiMn-LDH HNBs hybrid nanostructures exhibit outstanding electrochemical sensing capabilities for HCHO at a low operating potential (0.65 V). The detection limit is 2.1 × 10−4 mM (S/N=3) with a linear range of 3 × 10−3 mM to 7 mM. Satisfactory results are obtained for the detection of HCHO in food samples, implying a promising application in electrochemical HCHO sensing.