Papers by Author: Yong Feng Li

Abstract: The Pd-based oxidation catalysts on stainless steel wire mesh(SSWM) monolith were prepared by electroless plating method. The effect of two different acid bath (including HNO3-HF and concentrated HCl) on the surface morphology of SSWM substrate and the adhesion of palladium particles with substrate were firstly studied. Then the etched SSWM monoliths were used as support to prepare Pd/SSWM monolith catalysts by electroless plating method and their application in toluene catalytic oxidation was also studied. The results indicated that the optimal palladium loading was 0.3wt% and the calcination temperature was 600°C. And the catalyst etched by HNO3-HF showed better activity in toluene catalytic oxidation and worse adhesion of palladium particles with substrate than that etched by concentrated HCl.

Abstract: Catalytic combustion of toluene on Cu-Mn complex oxides was investigated. The catalysts were prepared by urea-based hydrothermal method and characterized by XRD and SEM. It was found that both the decrease of the Cu/Mn molar ratio and the increase of reaction time contributed to improving catalytic activity for toluene combustion. The temperature for 99% conversion of toluene (T₉₉) was lowered to 210°C. The main crystalline phases of Cu-Mn complex oxides were CuO and Cu_0.45Mn_0.55O₂. It was showed that the existence and high dispersion of Cu-Mn complex oxides were related to the catalytic combustion activity.

Abstract: The palladium-based catalyst of 0.36wt%Pd/cordierite honeycomb ceramics (CHC) without alumina interlayer film was prepared via a new electroless plating method. The results of activity test for complete toluene oxidation showed that the prepared catalysts had good catalytic activity and temperature resistance. The total oxidation temperature (T₉₉) for toluene was at 230°C for the catalyst calcined at 500°C. The scanning electron microscopy (SEM) results indicated that the particles of palladium phases were small and well dispersed on the CHC substrate surface. And the X-ray photoelectron spectrum (XPS) further revealed that both PdO state and adsorbed oxygen species participated and played a more important role in toluene oxidation reaction.

Abstract: Catalytic combustion of volatile organic compounds (VOCs) is a high efficient and low-polluted technique. In this paper, the palladium-based combustion catalysts on cordierite honeycomb ceramics (CHC) substrate without interlayer film — Pd/CHC, were prepared by electroless plating method, and the effect of preparing conditions for the catalysts on the catalytic performance of toluene combustion was mainly studied. The optimal conditions were confirmed as follows: plating bath temperature is 60°C, plating time is 30min, palladium salt concentration is 0.2g/L, and calcination temperature after plating is 500°C. Finally, the stability test further indicated that the Pd/CHC catalyst prepared by the optimal electroless plating conditions has good catalytic stability.

Abstract: The palladium-based combustion catalysts on cordierite honeycomb ceramics (CHC) substrate without interlayer film (Pd/CHC) were prepared by electroless plating method. By means of scanning electron microscopy (SEM) and BET specific surface area, it was found that the palladium phases on the prepared catalyst after calcination treatment at 500°C were well dispersed on substrate with small and uniform particles. The X-ray diffraction, energy dispersion X-rays (EDX) analysis, adherence test and temperature programmed reduction (H₂-TPR) analysis further indicated that the palladium phase had good adherence strength on the surface of CHC substrate and the moderate ratio of metallic Pd and PdO phase was only obtained on the catalyst calcined at 500°C . Moreover, the results of activity tests for toluene combustion showed that the 0.24%Pd/CHC catalyst had good low temperature catalytic activity and temperature-resistance property. The total combustion temperature (T₉₀) for toluene over catalyst calcined at 300, 500 and 900°C was at 239, 225 and 233°C respectively. And the toluene conversion could keep up above 97% during the stability test of Pd/CHC catalyst at 230°C for 105 h, indicating the good catalytic stability of the prepared catalyst.

Abstract: The palladium based combustion catalysts on FeCrAl alloy substrate (Pd/FeCrAl) were prepared by electroless plating method. By means of scanning electron microscopy (SEM), X-ray diffraction and BET specific surface area, it was found that the prepared catalyst after calcination treatment at 800°C could obtain utmost PdO phases, which were well dispersed on substrate with small and uniform particles. The EDX analysis and the adherence tests further indicated that a synergistic interaction was formed between palladium components and substrate on catalyst calcined above 600°C, which might be caused by α-alumina whiskers packaging palladium particles on the surface of substrate. Moreover, the results of activity tests for toluene combustion showed that the 0.1%Pd/FeCrAl catalyst had good low temperature catalytic activity and temperature-resistance property. The total combustion temperature (T90) for toluene over catalyst calcined at 600, 800 and 1000°C was at 218, 207 and 217°C respectively. And the toluene conversion could keep up above 99% during the stability test of Pd/FeCrAl catalyst at 210°Cfor 50 h, indicating the good catalytic stability of Pd/FeCrAl catalyst.

Abstract: Reverse micro emulsion method showed some advantages in the preparation of the catalyst MnBaAl11O19-δ with large surface area and high activity, when compared with sol-gel method or co-precipitation method. The influences of water content in reverse micro emulsion on nanostructure catalyst MnBaAl11O19-δ were discussed in this paper. The catalyst MnBaAl11O19-δ was prepared by reverse microemulsion method with a system consisted of 55% of n-heptane, 15% of emulsifier OP-10, 15% of 1-octanol and 15% of water (volume ratio). It resulted in the catalyst a length of 10-30nm plated-like phase and large surface area of 106 m2/g. The catalyst was applied in dimethyl ether combustion and it showed high activity with T10% at 160 °C and T90% at 300 °C. The recycle reverse micro emulsion was reused to prepare the catalyst MnBaAl11O19-δ. The catalyst MnBaAl11O19-δ prepared with that, still showed large surface area of 65m2/g and high activity with T10% at 170 °C and T90% at 320 °C in dimethyl ether catalytic combustion.