Acta Phys. -Chim. Sin. ›› 1988, Vol. 4 ›› Issue (01): 8-13.doi: 10.3866/PKU.WHXB19880103
• ARTICLE •
Wei Zhaobin*; Chen Yixuan; Li Wenzhao
The reduction and oxidation character of Pd-CuO/TiO_2 catalyst has been investigated, exploring, the effect of semiconductor support TiO_2 and metal Pd, using Pd-CuO/Al_2O_3 as a comparing system.By means of TPR, it was shown that Cue supported on TiO_2 was much more readily reduced than that on Al_2O_3 and without support. The temperatures of the respective reduction peak for Cue were ca.200, 265 and 285 ℃. If as low as 0.3 wt.% of Pd was present, then the reduction peak of Cue on TiO_2 was further shifted to below 100 ℃ while that on Al_2O_3 was hardly changed.The TPO spectra of catalyst sample pre-reduced by H_2 at 250 ℃ demonstrated the different behavior of supports TiO_2 and Al_2O_3 as well in correlation with XRD pattern, it revealed CuO on TiO_2 may be oxidized stepwise much more readily, i.e. Cu~0→Cu~+→Cu~(++), in contrast with the resistance to oxidation of CuO on Al_2O_3.These results could be explained by that TiO_2 as n-type semiconductor oxide can easily provide n-type defect, Ti~(3+) or oxygen vacancy, which might play the role of relay for charge transfer. Particularly in presence of noble metal, H_2 being strongly activated, the action of n-type defect was effectively enhaned so that the charge trasition between components was promoted. Thus the reduction and oxidation of CuO_x could proceed smoothly on TiO_2 but not so as it was supported on Al_2O_3.
Wei Zhaobin*; Chen Yixuan; Li Wenzhao. STUDIES ON THE REDUCTON AND OXIDATION CHARACTER OF Pd-CuO/TiO2 CATALYST[J].Acta Phys. -Chim. Sin., 1988, 4(01): 8-13.
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