Effects of precursor composition used in solution precursor plasma spray on the properties of ZnO coatings for CO2 and UV light sensing.

The potential of finely-structured zinc oxide (ZnO) coatings developed via solution precursor plasma spraying (SPPS) as CO 2 gas and UV light sensor was explored in this work. The coatings were deposited on stainless steel substrates using aqueous solutions of zinc nitrate and zinc acetate as precursors. The coatings' microstructures were studied in relation to the solution precursors used. Relatively porous coatings were obtained when using acetate as starting precursor compared to the coatings from the nitrate precursor. This was attributed to the different chemical routes of ZnO formation for each precursor droplet upon contact with plasma jet. Phase analysis confirmed the formation of polycrystalline ZnO having wurtzite structure from both precursors. The sprayed ZnO coatings showed good sensitivity and recovery towards UV light. Moreover, the coatings were sensitive towards carbon dioxide (CO 2) analyte gas but did not show any good recovery which was attributed to the microstructure of the coatings. These results showed the feasibility of SPPS process for the fabrication of finely-structured ZnO coatings as sensors of CO 2 gas and UV light. • (1) Polycrystalline ZnO coatings were developed via SPPS process using different starting solution precursors • (2) Microstructures were influenced by solution precursors used due to different chemical routes of ZnO formation in plasma jet • (3) Relatively porous coatings were obtained when using acetate as compared to using the nitrate one • (4) ZnO coatings showed good sensitivity towards CO 2 gas but do not show any good recovery • (5) ZnO coatings had good response and recovery when exposed to UV light [ABSTRACT FROM AUTHOR]