Detection of dimethyl methyl phosphonate – a simulant of sarin: The highly toxic chemical warfare – using platinum activated nanocrystalline ZnO thick films

Abstract

Nanocrystalline ZnO powder was prepared using ultrasonic atomization technique. Thick films of this powder were prepared using simple screen printing technique. Pt-modified-ZnO (platinum activated) films were obtained by dipping pure ZnO films into an aqueous solution of chloroplatnic acid for different intervals of time, followed by firing at 500 °C for 30 min. The sensing performance of the unmodified (pure) and Pt-modified ZnO (Pt–ZnO) films was tested on exposure of CWAs (chemical warfare agents) simulants, such as, dimethyl methyl phosphonate (DMMP), 2-chloroethyl ethyl sulfide (CEES) and 2-chloroethyl phenyl sulfide (CEPS). Both pure ZnO and Pt–ZnO films showed higher response to DMMP than their responses to CEES and CEPS. The simulant response, selectivity, response time and recovery time of the sensors were measured and presented. The role played by surface platinum species in the better simulant sensing performance is discussed.