Cu2ZnSnS4/CeO2 heterojunction with excellent sensing property for ammonia nitrogen in aqueous solution

A novel nanomaterial formed by a Cu2ZnSnS4 (CZTS)/CeO2 heterojunction with excellent electrochemical sensing for ammonia nitrogen was prepared by a microwave irradiation method combined with a hydrothermal method. The properties of the CZTS/CeO2 heterojunction were investigated by a series of characterizations such as Raman spectra, x-ray diffraction, scanning electron microscopy, thermogravimetric analysis, specific surface area (SSA), temperature-programmed desorption of ammonia and UV–vis spectroscopy. Nickel foam was used as a conductive frame electrode in order to enhance the sensitivity of the sensor along with the electrical conductivity, permeability and SSA. It is revealed by electrochemical measurements that the ammonia nitrogen oxidation reaction occurring in the sensing electrode of the CZTS/CeO2 heterojunction demonstrated regulation of Ip (mA) = 6.4 × 10−3C (mM)+ 0.1527 (R2= 0.9987) in a wide concentration range of 0–380.0 mM with a low detection of 6.0 μM according to the signal-to-noise ratio (S/N= 2). The CZTS/CeO2 heterojunction is expected to become a new candidate semiconductor nanomaterial for the electrochemical detection of ammonia nitrogen in an aqueous solution.