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应用X射线衍射、红外吸收光谱、脉冲色谱等技术,研究了Ag-V氧化物系催化剂的体相结构和表面酸碱性质及其与甲苯氧化合成苯甲醛的活性和选择性的关系。试验结果表明在V_2O_5中引入Ag后,催化剂的比活性下降,选择性提高,在 V/(V+Ag)=0.7(原子比)时,生成苯甲醛的选择性最高。X射线衍射分析指出其主要晶相结构Ag_(0.80)V_2O_5δ和Ag_(0.5)V_(2)O_5β。红外吸收光谱表明在900～1000cm~(-1)间有较强的吸收峰出现。Ag-V氧化物催化剂表面具有酸碱性,Ag的引入使酸度降低,碱度增高。而催化剂的组成、表面酸碱度与催化活性和选择性之间有良好的顺变关系。
The structure and surface acid-base properties of Ag-V oxide catalysts were investigated by X-ray diffraction, infrared absorption spectroscopy and pulse chromatography. Their relationship with the activity and selectivity of benzaldehyde oxidation by toluene oxidation was studied. The results showed that the specific activity of the catalyst decreased and the selectivity increased when Ag was introduced into V_2O_5. The selectivity to benzaldehyde was the highest at V / (V + Ag) = 0.7 (atomic ratio). X-ray diffraction analysis indicated that the main crystal structure Ag_ (0.80) V_2O_5δ and Ag_ (0.5) V_ (2) O_5β. Infrared absorption spectra showed that there was a strong absorption peak between 900 ~ 1000cm ~ (-1). The surface of Ag-V oxide catalyst is acidic and basic. The introduction of Ag decreases the acidity and increases the alkalinity. The catalyst composition, surface pH and catalytic activity and selectivity between the good relationship between.