钨基催化剂制备及其催化纤维素加氢反应研究
发布时间：2018-12-13 07:41
【摘要】：能源和环境是当今人类社亟待解决的重大问题,纤维素是自然界中储量最大的可再生生物质资源,主要是由D-葡萄糖通过β-1,4-糖苷键连接成的高分子直链化合物。使用钨基纳米催化剂催化纤维素氢制备高附加值的化学品对于解决能源危机具有重要意义。此外,改性后的钨基纳米催化剂在光催化治理水污染领域也具有良好的应用前景。本文采用浸渍法制备以MCM-41为载体,贵金属Ru、Pt、Pd、Rh和W03作为活性物质的催化剂,并将其应用于纤维素催化加氢。研究反应温度、反应时间、初始氢压、活性组分负载量和催化剂种类对纤维素转化率和乙二醇产率的影响,此外还探讨了Ru-WO3/MCM-41纤维素加氢机理。结果表明：贵金属Ru、Pt、Pd和Rh以及W03通过等体积浸渍法可以很好地分散到MCM-41的孔道中。在纤维素催化加氢反应中以Ru-WO3/MCM-41催化剂对乙二醇的选择性最好。采用2%Ru-15%WO3/MCM-41催化剂时,当反应温度为240℃,反应时间为0.5 h,氢气压力为4.0 MPa时,纤维素转化率和乙二醇的产率达到最大,分别为90.6%和55.6%,这主要是由于W物种能够断裂纤维素水解产生的葡萄糖的碳碳键,从而生成乙二醇等小分子醇。另外,本文还采用水热法合成了Mo掺杂的W03纳米片光催化剂,并对其在可见光照射下降解罗丹明B染料的性能进行研究。结果表明：Mo可以均匀地掺杂到了W03的表面以及体相中,并且不会改变W03纳米片的形貌以及晶格相。当使用纯W03作为催化剂时,罗丹明B溶液(pH 12)在经过3h的光照后降解率为59.2%;当使用1%Mo掺杂的W03催化剂时,罗丹明B的降解率提高至92.0%。Mo的掺杂将W03能带宽度从2.60eV降至2.51eV,同时Mo6+能与光生电子反应从而减少了光生电子和空穴的复合,提高光催化效率。
[Abstract]:Energy and environment are important problems to be solved urgently. Cellulose is the most abundant renewable biomass resource in nature. Cellulose is a kind of macromolecule straight chain compound which is connected by 尾 -glucose-4-glucoside bond. It is important to use tungsten-based nano-catalyst to catalyze cellulose hydrogen to produce high-value chemicals for solving energy crisis. In addition, the modified tungsten nanocatalysts also have a good application prospect in the field of photocatalytic treatment of water pollution. In this paper, the catalysts with MCM-41 as carrier and noble metal Ru,Pt,Pd,Rh and W03 as active substances were prepared by impregnation method, and were applied to the catalytic hydrogenation of cellulose. The effects of reaction temperature, reaction time, initial hydrogen pressure, loading amount of active components and type of catalyst on the conversion of cellulose and yield of ethylene glycol were studied. The hydrogenation mechanism of Ru-WO3/MCM-41 cellulose was also discussed. The results show that the noble metals Ru,Pt,Pd, Rh and W03 can be dispersed into the pores of MCM-41 by isobaric impregnation. Ru-WO3/MCM-41 catalyst has the best selectivity to ethylene glycol in the hydrogenation of cellulose. When the reaction temperature was 240 鈩，
本文编号：2376173
[Abstract]:Energy and environment are important problems to be solved urgently. Cellulose is the most abundant renewable biomass resource in nature. Cellulose is a kind of macromolecule straight chain compound which is connected by 尾 -glucose-4-glucoside bond. It is important to use tungsten-based nano-catalyst to catalyze cellulose hydrogen to produce high-value chemicals for solving energy crisis. In addition, the modified tungsten nanocatalysts also have a good application prospect in the field of photocatalytic treatment of water pollution. In this paper, the catalysts with MCM-41 as carrier and noble metal Ru,Pt,Pd,Rh and W03 as active substances were prepared by impregnation method, and were applied to the catalytic hydrogenation of cellulose. The effects of reaction temperature, reaction time, initial hydrogen pressure, loading amount of active components and type of catalyst on the conversion of cellulose and yield of ethylene glycol were studied. The hydrogenation mechanism of Ru-WO3/MCM-41 cellulose was also discussed. The results show that the noble metals Ru,Pt,Pd, Rh and W03 can be dispersed into the pores of MCM-41 by isobaric impregnation. Ru-WO3/MCM-41 catalyst has the best selectivity to ethylene glycol in the hydrogenation of cellulose. When the reaction temperature was 240 鈩，
本文编号：2376173
本文链接：https://www.wllwen.com/kejilunwen/huaxue/2376173.html
教材专著
