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早在1926年已知将硷金属盐加入钒催化剂中可显然增加其对二氧化硫氧化的催化活性.关于硷金属盐的助催化作用已有不少的研究工作.Frazer及Kirkpatrick发现K_2S_2O_7在钒催化剂的工作温度能溶解V_2O_5而生成熔盐.等对V_2O_5—K_2SO_4,V_2O_5—K_2S_2O_7体系的研究,等对V_2O_5—Na_2SO_4体系的研究,及Topsoe等对Rb,Cs,K,Na的焦硫酸盐与V_2O_5体系的研究都说明在工作温度时V_2O_5与以上盐类的体系已处于熔融状态.Topsoe等且认为其熔点降低是催化活性提高的原因。另一方面Neu mann等认为硷金属盐的作用是防止V_2O_5被SO_2还原为VOSO_4以致活性降低.发现钒钾催化剂在工作条件下可被SO_2还原.并认为这是钒钾催化剂的活性在450°突然降低,而使Arrhenius綫在450°左右发生破折的
It has been known that the addition of an alkali metal salt to a vanadium catalyst as early as 1926 clearly increases its catalytic activity for the oxidation of sulfur dioxide.Many studies have been made on the cocatalytic action of alkali metal salts.Frazer and Kirkpatrick found that K 2 S 2 O 7 in the vanadium catalyst The working temperature can dissolve V_2O_5 to form molten salt, etc. The research on V_2O_5-K_2SO_4, V_2O_5-K_2S_2O_7 system and other research on V_2O_5-Na_2SO_4 system and Topsoe ’s research on the reaction system of pyro-sulfate and V_2O_5 system of Rb, Cs, K and Na Of the studies have shown that at the working temperature V_2O_5 and the above salt system has been in a molten state.Topsoe so that their melting point is the reason for the increase in catalytic activity. On the other hand, Neumann et al. (2005) thought that the action of alkali metal salt is to prevent the reduction of V 2 O 5 from SO 2 to VOSO 4, and the activity of vanadium-potassium catalyst can be reduced by SO 2 under the working conditions and it is considered that the activity of vanadium- Lower, leaving the Arrhenius line breaking at about 450 °