碳黑前處理對PtRu/C催化表現的影響

Abstract

在本研究，對直接甲醇燃料電池之陽極催化劑支持物(碳黑)進行化學處理，並測試其對甲醇電氧化的催化活性。碳黑經由過錳酸鉀、過錳酸鉀加硝酸、硝酸以及過氧化氫處理而官能基化。利用FT-IR和XPS來測定碳黑上表面含氧官能基。從結果發現，碳黑經由這些氧化處理可以讓表面含氧官能基增加。 我們以兩種方式來合成出碳黑支持鉑釕催化劑：還原和吸附。並藉由XPS、ICP-AES、XRD和TEM來鑑定鉑釕催化劑被支持在未處理和已處理的碳黑上。結果發現經由還原方式座落在碳黑之鉑釕的數量與碳黑表面含氧官能基的量有ㄧ定的相關性。碳黑表面的含氧官能基能增加表面上的可濕性，因而能讓前驅物更容易還原於碳黑表面上。利用對甲醇的CV和EIS實驗來測定催化劑的電催化活性。由結果知道，來自於經過官能基化的碳黑上之鉑釕的電催化性具有更好表現度，其中特別是經過過氧化氫修飾的碳黑。The chemical treatment of the carbon black support on the performance for methanol electrooxidation was studied. The carbon black was functionalized with KMnO4, KMnO4+HNO3, HNO3 and H2O2. The surface oxygen complexes of the carbon black were determined with FT-IR and XPS. The results showed that the surface oxygen complexes of the carbon black increase after the oxidation treatments. The PtRu catalysts were deposited on the carbon black with two different methods: reduction and adsorption. PtRu catalysts supported on the untreated and treated carbon blacks were characterized with XPS, ICP-AES, XRD, and TEM. The loading of the PtRu by reduction was related to the amount of surface oxygen complexes on the carbon black. The presence of surface oxygen complexes improves the wettability of the carbon black and, hence make the reduction of the precursors easier. The electrocatalytic activities of PtRu on the pretreated carbon black were investigated with the CV and EIS measurements in the oxidation of methanol. The pretreatment of carbon black, especially with H2O2, significantly improves the electrocatalytic performance.