(207c) One-Step Synthesis of Transition Metal Doped Titanium Dioxide Catalysts for Oxygen Removal

Carbon dioxide (CO₂) capture and sequestration have been considered as promising techniques to alleviate the emission of greenhouse gas. However, it is difficult to cost effectively deploy them in conventional coal-fired combustion plants due to the diluted CO₂ concentration in the flue gas, requiring additional methodologies for concentrating the stream. An oxy-fuel combustion technique which uses pure oxygen (O₂) to obtain a concentrated CO₂ stream has been developed to solve this problem, and has obtained a sequestration-ready gas stream. However, this gas stream contains O₂ as well as CO₂, which can cause damage to the gas infrastructure through corrosion. To overcome this shortcoming, catalytic O₂ removal system with hydrocarbons has been recently applied. In this study, we develop 1) a one-step synthesis of transition metal doped catalysts and 2) an efficient catalytic O₂ removal system with methane (CH₄). To achieve this, we first synthesize different transition metal (Cu, Fe, Ir, Ni, Mn, Rh, Ru) doped titanium oxide (TiO₂) catalysts in a flame aerosol reactor. Compared to liquid phase synthesis methods such as wet impregnation and sol-gel, flame synthesis is a gas phase technique that can produce homogeneous nanoparticles and can be scaled up for high throughput production. The different catalysts are characterized by BET, X-ray diffraction, scanning electron microscopy and transmission electron microscopy to relate nanoparticle characteristics to performance. Second, we test the synthesized catalysts for O₂ removal with CH₄ to optimize the catalyst. Third, we optimize the synthesis conditions (dopant concentration (0-5 wt.%), fuel flow rate (0.8-1.8 LPM)) to get the highest O₂ removal efficiency.