CONFIRMATION OF INDENPENDENT Au AND Pd ACTIVE SITE of Au-Pd/Fe(OH)x CATALYSTS BY 197Au MOSSBAUER SPECTROSCOPY
文献类型：会议论文
| 作者 | Qiao BT(乔波涛) ; Wang AQ(王爱琴) ; Wang JH(王军虎) ; M.Takahashi ; Wang XD(王晓东) ; Zhang T(张涛) |
| 出版日期 | 2009-07-19 |
| 会议名称 | internatinal conference on the applications of the mossbauer effect |
| 会议日期 | 2009-7-19 |
| 会议地点 | austria |
| 页码 | 36/1 |
| 通讯作者 | tao zhang |
| 中文摘要 | catalytic oxidations of co, h2 and co+h2 over supported noble metals such as pd, au and pt catalysts at lower temperature have attracted considerable attention. especially, one of potential applications of total co-oxidation of h2+co at lower temperatures is co resistant hydrogen fuel cells.1 at ambient temperature, it is well known that pt and pd are the most effective catalysts for h2 oxidation, while supported au catalysts are intrinsically more active for co oxidation. therefore, catalysts possess independent active site of au and pd/pt could be theoretically effective for this reaction. in this work, a novel au-pd/fe(oh)x catalysts was prepared and au-197 mössbauer spectroscopy was used to confirm the independent au and pd active sites. 1.1 wt% au/fe(oh)x, 1.6 wt% pd/fe(oh)x, 1.1-1.6 wt% au-pd/fe(oh)x catalysts and 1.2 wt% au/fe2o3, 1.8 wt% pd/fe2o3, 1.2-1.8 wt% au-pd/fe2o3 catalysts, which were prepared for compare purpose, were all prepared by co-precipitation method without calcined or calcined at 500 oc. the catalytic activity was evaluated with the lowest temperatures (ltt) at which co or/and h2 was totally oxidized. the results of the catalytic activity measurements are listed in table 1. as expected, au/fe(oh)x catalyst (entry 1) is more active for co oxidation than for h2 oxidation while pd/fe(oh)x catalyst (entry 2) is more active for h2 oxidation than for co oxidations in air. however, the mixture gas of co+h2+o2 can not be removed compeletly at ambient temperature over both the catalysts. as for au-pd/fe(oh)x (entry 3) catalyst, as expected, is both active for co and h2 oxidations in air because of its independent active site of au and pd. in the mixture gas of co+h2+o2, although h2 oxidations on pd active site was inhibited by the existence of co, co+h2+o2 can be totally removed at 25 oc. for comparison purpose, the activity of au/fe2o3, pd/fe2o3 and au-pd/fe2o3 were also tested, table 1. the activity decreased greatly that the ltt of the mixture gas of co+h2+o2 over these three catalysts were all above 110 oc. the activity of au-pd/fe2o3 for co+h2+o2 is the middle among that of the three catalysts, indicating that aupd alloy were formed during calcination at high temperature. au-197 mössbauer spectroscopy was used to confirm the independent active site of au and pd. as shown in table 2 and fig. 1, au mainly existed as auooh•xh2o2 and au0 over au/fe(oh)x and au/fe2o3 catalysts. over au-pd/fe(oh)x catalyst, au existed as auooh•xh2o and au0 species and no aupd alloy were observed, indicating that au-pd/fe(oh)x possess the independent active site of au and pd. over au-pd/fe2o3 catalysts, however, au existed as au0 and aupd alloy, indicating that, after being calcined at 500 oc, the aupd alloy were formed partially and the independent active site were destroyed. |
| 会议主办者 | vienna university of technology |
| 学科主题 | 物理化学 |
| 语种 | 中文 |
| 源URL | [http://159.226.238.44/handle/321008/113520]  |
| 专题 | 大连化学物理研究所_中国科学院大连化学物理研究所 |
| 推荐引用方式 GB/T 7714 | Qiao BT,Wang AQ,Wang JH,et al. CONFIRMATION OF INDENPENDENT Au AND Pd ACTIVE SITE of Au-Pd/Fe(OH)x CATALYSTS BY 197Au MOSSBAUER SPECTROSCOPY[C]. 见:internatinal conference on the applications of the mossbauer effect. austria. 2009-7-19. |
入库方式： OAI收割
来源：大连化学物理研究所
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