The Preparation Of 3DOM And Its Application For Preferential Oxidation Of CO

The preferential oxidation of carbon monoxide (PROX) is an optimal method for the purification of CO in hydrogen-rich gases used for fuel cells. And it is one of the key techniques for the application of fuel cells to develop catalysts with good catalytic performance for CO preferential oxidation. The main purpose of this paper is to prepare a CuO-CeO₂ catalyst with three-dimensional macroporous structure (3DOM) which can enhance the selectivity of the PROX reaction. The further research is on preparing 3DOM--monolith CuO-CeO₂ catalyst which could be used in the hydrogen system of the fuel cells.In this paper, we prepared 3DOM CuO-CeO₂ catalysts with polystyrene (PS) as a template, and tested the catalytic activity in PROX reaction. The main conclusions are as following:1. The addition of polar solvent can change the diameter of the colloid template. A facile method to control the diameter of the colloid template is adding a certain amount of ethanol in the reagent. This can help us control the diameter of the 3DOM catalysts.2. The vapor self-assembly method is a time-saving and effective way to prepare the colloid template. We got an ordered template with colorful light with this method.3. During the filling step, precursor solution is the nitrite and citric acid in ethanol, and the best time of filling and drying cycle is three.4. The PS template modified by methacrylic acid is excellently ordered and colorful. The 3DOM catalysts with this template have nice order, too.5. 3DOM CuO-CeO₂ catalysts exhibit excellent catalytic activity for PROX reaction. Especially at high space velocity (80,000 and 160,000 mL/(h.gcat)), the selectivity of these catalysts are much better than particle catalysts.6. 3DOM CuO-CeO₂ catalyst calcined at 550℃with 15wt.% copper content shows the best catalytic performance for PROX reaction. From 125 to 200℃, it can completely remove CO with gas mixture of 1vol.% CO, 1vol.% O₂, 50vol.% H₂ in N2.7. The addition of CO₂ and/or H₂O in the reaction gases lead to decrease of CO conversion and selectivity over 3DOM CuO-CeO₂ catalysts.