K_2O对合成DMC用Cu- Ni/V_2O_5- SiO_2催化剂性能的影响

K_2O是多种固体催化剂的有效助剂 .大多数金属表面对 CO_2的吸附非常弱，在过渡金属中加入碱金属助剂可以促进 CO_2的吸附活化 1， 2].近期对这方面的研究主要集中在 Pt3]、 Cu4]、 Ru5]和 Fe6]等单晶金属面上 .我们已报导过 Cu- Ni/V2O5- SiO_2(VSiO)催化剂表面 CO_2和 CH_3OH吸附及其反应性能 7， 8].本研究将 K_2O助剂引入到 Cu- Ni/VSiO催化剂中，进一步考察了 K_2O助剂对 CO_2和 CH_3OH吸附和反应性能的影响 .1实验部分 　　采用 Cu、 Ni氨络合物混合硝酸盐水溶液 (含 KNO3， K占 Cu、 Ni总原子数 5～ 15…

Effect of K_2O on Properties of Cu- Ni/V2O5- SiO_2 Catalyst for the Synthesis of Dimethyl Carbonate

V2O5-SiO2(VSiO) supported Cu-Ni-K2O catalysts for the synthesis of dimethyl carbonate were prepared using isovolumic impregnation. Based on TPR,TPD, IR and micro-reactor techniques, the effect of K2O on the adsorption and reaction of CO2 and CH3OH on the catalyst were characterized. The results show that addition of K2O exerts obvious influence on the charge distribution of the active sites on Cu-Ni/VSiO catalyst,increases the intensities of CO2 horizontal adsorption state, while that of the dissociation state of methanol descends. When the ratio of K is above 15 ％ , K2CO3 is formed on the catalyst. Moreover,the main reaction products of CO2 and CH3OH on Cu-Ni-K2O/VSiO catalyst are still DMC, H2O, CO and CH2O,and with the addition of K2O, the conversion of reactants rise, but the selectivity of by-products decreases.