Diesel exhaust gases such as NO_x and SO_x are significant contributors to pollution in today’s atmosphere. The International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI has a tiered system for regulating these gases from marine diesel engines. The current standard, Tier III, limits the NO_x emissions based on a vessel’s horsepower. We have developed a catalyst material to treat the exhaust gases that are already mixed in a wet marine diesel engine. Our approach is based on perovskite photovoltaic architecture using fluorine-doped tin oxide (FTO) glass substrates coated with four layers applied by doctor blading. The first two being a TiO₂ layer and a mesoporous TiO₂ layer, then a perovskite layer and V₃O₇ layer respectively. The perovskite layer solution was formed from 0.3481g FAI, 1.0125g PbI₂, 0.1465g PbBr₂, and 0.0449g methylammonium bromide (MABr) in 2mL (4DMF:1DMSO) and 105.2 µL cesium iodide (CsI) solution (9.7430g CsI in 25mL DMSO) to activate in a conical vial. The mixed-valent vanadium oxide layer was formed by hydrothermal synthesis of 0.2275g vanadium oxide (V₂O₅) and 0.005g 4-aminophenol (H₂NC₆H₄OH) at 180°C for 48 hours. Catalyst material composition was confirmed by XRD & XRF spectroscopies. Model diesel exhaust was prepared by bubbling NO₂ gas through artificial seawater, and catalytic activity by analysis of the fluids both before and after catalytic treatment for nitrite (NO₃^-) and nitrate (NO₃^-) concentration via Hach spectrometry.

Clifford Murphy

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