High surface area Cu2ZnSnS4 nanosheets synthesized by microwave irradiation method: A material for detecting ammonia-ammonium ions in wastewater

A highly sensitive and selective electrochemical sensor based on porous Cu 2 ZnSnS 4 (CZTS) nanosheets is required for detecting ammonia-ammonium ions (NH 3 –NH 4 + ). Porous CZTS nanosheets synthesized by microwave irradiation method were characterized by Raman, XRD , SEM, TEM , BET, DLS and NH 3 -TPD. The porous nanosheets of CZTS-30 irradiated for 30 min with a surface area of 51.3 m 2  g −1 are significant material and possess many important active sites for NH 3 –NH 4 + oxidation . The electrode was made of a glassy carbon electrode (GCE) modified by CZTS-30. It was revealed by electrochemical measurements that there were two linear ranges for NH 3 –NH 4 + . One was the high concentration ranging from 1.0 mM to 600.0 mM ( R 2  = 0.9989) with a sensitivity of 8.29 μA mM −1  cm −2 , and the other was the low concentration between 0.1 mM and 1.0 mM ( R 2  = 0.9990) with a high sensitivity of 96.14 μA mM −1  cm −2 . It showed a detection limit of 30 μM (S/N = 10) for the sensor in NH 3 –NH 4 + solution mixed with 0.5 mM H 2 SO 4 at a fixed scan rate of 20 mV s −1 . This sensor also demonstrated desirable stability, reversibility and selectivity to NH 3 –NH 4 + . The CZTS/GCE is believed to become a new candidate structure for the electrochemical detection of NH 3 –NH 4 + .