介孔碳负载金属催化剂对纤维素热裂解反应的影响

为了研究介孔碳负载金属催化剂对纤维素热裂解反应的影响，分别采用三元组装法和浸渍法制备介孔碳（MC）和负载型金属催化剂NaOH/MC、K₂CO₃/MC和AlCl₃/MC，使用气体吸附法（BET）和扫描电子显微镜-能谱表征催化剂，通过热裂解-气相色谱质谱联用（Py-GC/MS）来研究介孔碳负载金属催化剂对纤维素热裂解产品分布的影响。结果表明:催化剂具有比表面积839~1 081 m²/g、平均孔径4.76~5.03 nm、孔容0.92~1.14 mL/g。其Na、K和Al负载量分别为0.05%~4.6%、0.06%~12.2%和0.8%~5.6%。3类催化剂皆能有效促进纤维素热降解，使其向小分子产物方向进行。随着碱金属Na和K负载量增加，裂解产物中脱水糖呈降低趋势，产品中羟基乙醛和羟基丙酮的选择性高。当Na负载量为3.5%时，羟基丙酮含量最高达无催化剂条件下的60倍。当使用铝催化剂时，纤维素转化为糠醛，糠醛量为无催化剂条件下9.5倍。与相同负载的微孔活性炭催化剂相比，介孔碳催化剂从金属负载量和催化效果上都明显更优。

Effect of Mesoporous Carbon Supported Metal Catalysts on Cellulose Pyrolysis

To study the effect of mesoporous carbon-supported metal catalysts on cellulose pyrolysis， mesoporous carbon （MC） and MC supported catalysts of NaOH/MC， K₂CO₃/MC and AlCl₃/MC were prepared by ternary assembly and the impregnation method， respectively. Catalysts were characterized by using the Brunauer-Emmett-Teller method and the scanning electron microscopy-energy-dispersive X-ray spectroscopy. The effects of MC supported metal catalysts on the distribution of cellulose pyrolysis products were investigated by using pyrolysis-gas chromatography-mass spectrometry. The results show that the catalysts have specific surface areas of 839-1 081 m²/g， an average pore diameter of 4.76-5.03 nm， and pore volumes of 0.92-1.14 mL/g. The Na， K and Al loadings are 0.05%-4.6%， 0.06%-12.2% and 0.8%-5.6%， respectively. All three types of catalysts can effectively promote the thermal degradation of cellulose to generate small-molecule chemicals. As the loading of alkali metals （Na and K） on MC increases， anhydrosugars in pyrolysis products tend to decrease， and the selectivity of glycolaldehyde and hydroxyacetone is high. When the Na loading is 3.5%， the hydroxyacetone content is 60 times that of the noncatalytic condition. In the pyrolysis reaction catalyzed by AlCl₃/MC， celluloseis converted into furfural， and the amount of furfural obtained is 9.5 times that under the noncatalytic condition. Compared with microporous activated carbon supported catalysts， mesoporous carbon supported catalysts are significantly better in both metal loading and catalytic performance.