纳米多孔钌催化纤维素高效转化制备甲烷

Highly Efficient Conversion of Cellulose into Methane over Nanoporous Ru Catalyst

以钌、铝两种金属制备了纳米多孔钌催化剂,并将其应用于催化纤维素制甲烷反应中。对纤维素和催化剂进行了XRD、SEM、TEM和XPS表征,并对催化过程进行了温度和压力考察。结果表明：在反应温度220℃、初始氢气压力0.5 MPa下反应8 h,纤维素转化率为75.8%,甲烷选择性达到82.2%。具有纳米多孔结构的催化剂稳定性良好,可循环套用10次,甲烷收率保持在73.2%~79.5%。考察了纤维素的转化历程和反应前后纤维素结构变化。结果表明：纤维素制备甲烷反应分为酸催化的水解过程和纳米多孔钌催化的加氢过程两个阶段。钒改性纳米多孔钌双功能催化体系可以提高纤维素向甲烷转化,纤维素的转化率及甲烷的收率分别达到了49.3%和38.8%。

Nanoporous Ru was prepared with two kinds of metal（ruthenium and aluminum）, and employed as catalyst in the transformation of cellulose to methane. The cellulose and catalyst were characterized by XRD, SEM, TEM and XPS. The effects of temperature and H2 pressure on the hydrogenation of cellulose were studied. The results showed that under the following reaction conditions： reaction temperature 220 ℃, initial H2 pressure 0.5 MPa, reaction time 8 h, the conversion of cellulose（75.8%） and selectivity of methane（82.2%） were obtained. The catalyst with nanoporous structure still remained good stability after being reused ten times, and the yield of CH4 ranged from 73.2% to 75.9%. The reaction mechanism of cellulose transformation and structure change of cellulose in the process were investigated. It was found that cellulose transformation into methane was consisted of acid-catalyzed hydrolysis process and nanoporous Ru-catalyzed hydrogenation process. Vanadium modified nanoporous Ru bifunctional catalyst could significantly promote the transformation of cellulose into methane. The conversion of cellulose and yield of methane were 49.3% and 38.8%, respectively.