High-purity In2O3 nanoparticles were recovered from scrap indium tin oxide substrates in a stepwise process involving acidic leaching, liquid-liquid extraction with a phosphine oxide extractant, and combustion of the organic phase. The morphological and structural parameters of the recovered nanoparticles were investigated to support the formation of the desired products. These In2O3 nanoparticles were used for sensitive sensing of ammonia gas using a four-probe electrode device. The proposed sensor offered very quick response time (around 10 s) and highly sensitive detection of ammonia (at a detection limit of 1 ppm).
Bhardwaj, S. K., Bhardwaj, N., Kukkar, M., Sharma, A. L., Kim, K. H., & Deep, A. (2015). Formation of high-purity indium oxide nanoparticles and their application to sensitive detection of ammonia. Sensors (Switzerland), 15(12), 31930–31938. https://doi.org/10.3390/s151229895