Study on Catalytic Oxidation of Carbonmonoxide over Nano-Size Platinum + Alumina Composite

Nano-size platinum particles were synthesized by chemical reduction of Pt⁺⁴ ions in water-in-oil microemulsion. As synthesized platinum nanoparticles have been characterized using TEM and XRD techniques. Platinum (2%)+Alumina composite was used as a catalyst for carrying out the oxidation of CO to CO₂, over 50–500°C, in a suitably designed converter comprising a vertical quartz tube connected to a quadrupole mass spectrometer. Effects of [Water]/[Surfactant] ratio and the presence of polyethylene glycol (PEG) in the microemulsion on the size and catalytic efficiency of as-synthesized platinum nanoparticles have been investigated. The size of platinum nanoparticles grows further on increasing [Water]/[Surfactant] ratio in the microemulsion composition. Whereas, using pure alumina as catalyst, conversion of CO to CO₂ occurs at 300°C, such conversion occurs at much lower temperature (225°C) using alumina+Pt (2%) as catalyst. CO to CO₂ conversion temperature is further lowered to 200°C when the platinum nanoparticles synthesized in microemulsion, stabilized by polyethylene glycol (PEG), are used in the above composite catalyst.