Shoucang Shen

Mechanism of selective catalytic reduction of NO in the presence of excess O2 over Pt/Si-MCM-41 catalyst

The reaction mechanism for the selective catalytic reduction (SCR) of nitric oxide (NO) over Pt/Si-MCM-41 catalyst has been studied by XPS and in-situ Fourier transform infrared (FTIR) spectroscopies as well as TPR. The XPS results indicate that Pt species are reduced during the reaction of NO-SCR in the presence of excess oxygen. The reduced Pt species are found not to be completely oxidised after they have been in contact with NO or O2 at the reaction temperature. FTIR results indicate that CO is one of the reaction intermediates taking part in the selective reduction of NO. The possible reaction mechanism for the selective catalytic reduction of NO over Pt/Si-MCM-41 catalyst is proposed.

Kinetic studies of selective catalytic reduction of nitric oxide by propylene on Pt/MCM-41 catalyst

Abstract Reaction kinetics for selective catalytic reduction (SCR) of nitric oxide (NO) over 1% Pt/MCM-41 catalyst has been investigated at temperatures ranging 150–500°C under steady and transient state conditions. The reduction of NO is found to be promoted by a small amount of oxygen when the concentration of oxygen is less than that of the critical oxygen concentration required for stoichiometric oxidation of C3H6. Above the critical oxygen concentration, an optimal reaction temperature for optimal NO conversion is observed and the optimal NO conversion decreases with the increase of oxygen concentration. Two distinct kinetic regions are observed: one at the reaction temperature below and the other one above that required for optimal NO conversion. The NO reduction rate is suggested to be controlled by the activation rate of C3H6 at low temperatures and by the external diffusion rate of reactants at high temperatures.

Hydrothermal Synthesis of Zn-Al-O Composite Nanorods

This paper reported that nanorods of Zn-Al-O composites could be synthesized through hydrothermal process and followed by solid reaction during calcination. The nanorods composites showed high thermal stability up to 900 °C without observed sintering between individual nanoparticles.