【摘要】：能源和環(huán)境是當(dāng)今人類社亟待解決的重大問(wèn)題,纖維素是自然界中儲(chǔ)量最大的可再生生物質(zhì)資源,主要是由D-葡萄糖通過(guò)β-1,4-糖苷鍵連接成的高分子直鏈化合物。使用鎢基納米催化劑催化纖維素氫制備高附加值的化學(xué)品對(duì)于解決能源危機(jī)具有重要意義。此外,改性后的鎢基納米催化劑在光催化治理水污染領(lǐng)域也具有良好的應(yīng)用前景。本文采用浸漬法制備以MCM-41為載體,貴金屬Ru、Pt、Pd、Rh和W03作為活性物質(zhì)的催化劑,并將其應(yīng)用于纖維素催化加氫。研究反應(yīng)溫度、反應(yīng)時(shí)間、初始?xì)鋲骸⒒钚越M分負(fù)載量和催化劑種類對(duì)纖維素轉(zhuǎn)化率和乙二醇產(chǎn)率的影響,此外還探討了Ru-WO3/MCM-41纖維素加氫機(jī)理。結(jié)果表明：貴金屬Ru、Pt、Pd和Rh以及W03通過(guò)等體積浸漬法可以很好地分散到MCM-41的孔道中。在纖維素催化加氫反應(yīng)中以Ru-WO3/MCM-41催化劑對(duì)乙二醇的選擇性最好。采用2%Ru-15%WO3/MCM-41催化劑時(shí),當(dāng)反應(yīng)溫度為240℃,反應(yīng)時(shí)間為0.5 h,氫氣壓力為4.0 MPa時(shí),纖維素轉(zhuǎn)化率和乙二醇的產(chǎn)率達(dá)到最大,分別為90.6%和55.6%,這主要是由于W物種能夠斷裂纖維素水解產(chǎn)生的葡萄糖的碳碳鍵,從而生成乙二醇等小分子醇。另外,本文還采用水熱法合成了Mo摻雜的W03納米片光催化劑,并對(duì)其在可見(jiàn)光照射下降解羅丹明B染料的性能進(jìn)行研究。結(jié)果表明：Mo可以均勻地?fù)诫s到了W03的表面以及體相中,并且不會(huì)改變W03納米片的形貌以及晶格相。當(dāng)使用純W03作為催化劑時(shí),羅丹明B溶液(pH 12)在經(jīng)過(guò)3h的光照后降解率為59.2%;當(dāng)使用1%Mo摻雜的W03催化劑時(shí),羅丹明B的降解率提高至92.0%。Mo的摻雜將W03能帶寬度從2.60eV降至2.51eV,同時(shí)Mo6+能與光生電子反應(yīng)從而減少了光生電子和空穴的復(fù)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，

本文編號(hào)：2376173