硝酸铈预处理菊芋秸秆高效制备纳米酶/多孔碳复合材料的热解机理研究

Jerusalem artichoke is an emerging cash and energy crop. Due to its high stress tolerance and adaptability, the cultivated area of Jerusalem artichoke continues to grow in China. Since the long stalks of Jerusalem artichoke (as long as 1~3 m) are rich in lignin, improper disposal of the stalks will cause severe problems for agricultural environment. However, complex pretreatment and low efficiency of conventional utilizing methods make them inapplicable for large-scale disposal of Jerusalem artichoke stalks. Therefore the development of efficient approaches of Jerusalem artichoke stalk utilization draws much attention. Biomass provides a rich natural carbon source for synthesis of porous carbon materials that serve as excellent supporting matrix for nanozymes. In preliminary studies, we have synthesized nanoceria loaded porous carbon by in situ pyrolysis of cerium nitrate pretreated Jerusalem artichoke stalks and found that the nanoceria/porous carbon nanocomposite shows exceptional charge transfer rate and electrochemical catalytic activity. Therefore in this proposal we intend to comprehensively study the reaction pathways and interaction mechanisms of co-pyrolysis of cerium nitrate pretreated Jerusalem artichoke stalks, as well as the regulatory mechanism of synthesis of porous carbon matrix and effective nanoceria loading for electrochemical performance enhancement. The success of the project will highly improve the efficient utilization of Jerusalem artichoke stalk biomass, and provide a native loading approach for the production of nanozyme/porous carbon nanocomposite, thus proving of great significance in the fields of agricultural waste utilization and electrochemical material fabrication.

菊芋是一种新兴的经济与能源作物。由于抗逆性强、适应性广、改善土壤，种植规模不断扩大。菊芋秸秆长达1~3米，其中富含木质素，处理不当会给农业生产环境带来负担。常规的菊芋秸秆利用方式前处理复杂、效率低，不能满足大规模处理的需求。因此开发菊芋秸秆的高效利用方式已经引起重视。生物质是合成多孔碳材料的天然碳源，而多孔碳可作为负载纳米酶的优良基质。前期研究中申请人先通过硝酸铈预处理菊芋秸秆，再原位热解的方式高效制备了纳米氧化铈负载的多孔碳，具有卓越的电荷传递和电化学催化性能。因此本项目拟深入研究硝酸铈预处理的菊芋秸秆热解过程的化学反应机理和相互作用机制，以及可提高电化学性能的多孔碳载体成型和纳米氧化铈有效负载的调控机制。本项目成果将提高菊芋秸秆生物质的高效利用水平，并为制备高电化学性能的纳米酶/多孔碳复合材料提供优良的原生途径，在农业废弃物增值利用和电化学材料制备等跨学科领域都具有重要意义。

传统的菊芋秸秆利用工艺复杂、效率较低、处理能力有限，不能满足大规模处理的需求。针对这一问题，本项目利用硝酸铈预处理菊芋秸秆芯热解制备纳米氧化铈/多孔碳复合材料，并探索其制备过程的热解动力学特性、分析共热解的化学反应机理和相互作用机制，以引导多孔生物炭载体成型及氧化铈纳米颗粒有效负载，在此基础上制备高电化学性能的纳米氧化铈/多孔碳复合材料。项目组分析了硝酸铈预处理的菊芋秸秆芯和菊芋秸秆芯的热解失重规律，确定热解反应特别是固态产物耦合生成的重要温度区间；建立热失重过程的动力学模型，获得如反应活化能等动力学参数，解析热解反应的动力学特性。并对不同热解温度制备的纳米氧化铈/多孔碳复合材料进行理化性质表征，分析其合成机制。进一步以纳米氧化铈/多孔碳复合材料修饰金电极，表征修饰后电极的交流阻抗和测试循环伏安特性，由此衡量复合材料的电化学性能，发现氧化铈/多孔碳复合材料表现出了优异的电化学催化能力，可以很好地提高SGGT传感器对日落黄的检测性能。分析复合材料的理化性质和耦合效应对其电化学性能的作用，明确影响其电化学性能的关键因素；优化制备高电化学性能的纳米氧化铈/多孔碳复合材料的工艺条件。