非選擇性釩/銅金屬活性碳觸媒氮氧化物還原活性之探討

Vanadium/Copper Embedded Activated Carbon Catalyst for deNOx Applications

本研究以碳觸媒進行選擇性觸媒還原法（SCR）及非選擇性觸媒還原法（NSCR）研究結果發現，在眾多碳觸媒中VN5碳觸媒最具有NO還原活性，於SCR反應中於450℃還原反應溫度達100%NO轉化率，在NSCR反應於500℃還原反應溫度NO轉化率達58%，由SEM分析結果證實於含浸液中添加微量銅金屬確實可促使釩金屬均勻分散於碳觸媒上，促使碳觸媒在NO還原反應過程中增加氣體與還原活性金屬接觸機會，其中以VN碳觸媒最具此特徵，XRD分析結果顯示出VN系列雙金屬碳觸媒，活化金屬以V2O5、V2O3、CuO、Cu^0四種晶相燒結於碳觸媒上，且受含浸劑中釩/銅比例之影響，隨含浸劑中釩金屬量增加，主要活化金屬晶相逐漸往具NO還原活性之V2O5晶相發展。BET分析結果顯示VN2碳觸媒比表面積雖達1024 m^2/g，但無上述之物化特性，促使VN2碳觸媒呈現較低NO還原活性。本研究結果得知燒結於碳觸媒上活化金屬分散性、活化金屬種類及晶相結構是影響釩/銅型碳觸媒NO還原活性之主要因素，其碳觸媒比表面積並非為主要影響因子。

It was found that the VN5 is the most active catalyst in SCR and NSCR tests. In the case of SCR, almost 100% NO reduction can be achieved under testing conditions at 450℃. On the other hand, 58% NO reduction was found in NSCR under testing condition at 500℃. The high conversion rate of NO reduction was due to the well V2O5 distribution on the carbon matrix which is contributed by the copper impregnating. The increase in amount of active siites and adsorption reactant enhanced the NO conversion in SCR. Based on the results of this study, it was found that VN catalysts showed the more reduction activity than VN, VB, and CB catalyst. XRD analysis indicated that impregnating metals present as V2O5, V2O3, CuO, and Cu^0 forms on the carbon catalyst. The amount of metal oxides strongly depends on the impregnating metal ratio in preparation. With increasing the vanadium ratio in preparing solution, more V2O5 was formed on the catalyst which was identified by the XRD analysis. In this study, VN2 catalyst showed a large surface area （1024 m^2/g） but the poor metal distribution and crystal form limited the activity in SCR. It is concluded that the distribution of active sides, crystal form of active metal, and active metal dominated the SCR and NSCR activity of V/Cu catalyst. The distribution of active sides and crystal form of active metal plays the main role to dominate the efficiency of SCR and NSCR