钙钛矿型稀土复合氧化物催化剂上一氧化碳的选择氧化

考察了在钙钛矿型稀土复合氧化物催化剂上，氢气中一氧化碳选择氧化的催化性能，发现该催化剂具有优良的催化活性和选择性。LaMnO3中的锰被铜部分取代后可以提高其催化活性，当其中的镧再被锶或钡部分取代后所得的催化剂的催化活性进一步提高。其中以La0.8Sr0.2Mn0.5Cu0.5O3的催化活性为最佳，在该催化剂上，在40 000 mL·g－1·h－1下，155 ℃时CO可被完全转化为CO2，此时的选择性达54%，与铂催化剂的性能相近。反应气中加入CO2时，CO转化率下降，但选择性有所提高；加入水蒸气则使CO的转化率和反应选择性均下降。

Preferential oxidation of CO in H2 over perovskite-type oxides

The catalytic performance of LaMnO3, La-Mn1-x-CuxO3, La0.8Sr0.2-Mn1-x-CuxO3, and La0.8Ba0.2-Mn1-x-CuxO3 for the title reaction was tested in the gas mixture of 1% CO, 0.5%～2% O2, 50% H2 in N2 and at a space velocity of 40 000 mL·g－1·h－1. The results show that the partial substitution of Cu for Mn in LaMnO3, and the partial substitution of Sr or Ba for La in La-Mn1-x-CuxO3 can enhance its catalytic activity. Among the catalysts investigated, the highest catalytic activity was observed over La0.8Sr0.2Mn0.5Cu0.5O3 catalysts: CO was completely converted to CO2 at 155 ℃ with a corresponding selectivity of 54%, which is close to the catalytic performance of some platinum catalysts. The conversion of CO was lowered with the addition of 15% CO2 in the reactant gas. The addition of 10% H2O in reactant gas reduced the CO conversion more markedly.