分级孔SiC@Pd微纳中空纤维构建及其气敏机制

Gas sensors which can be applied in harsh environments have triggered wide demands in various military fields including aero spacing and nuclear engineering. This item mainly focuses on exploring gas-sensing materials with high sensitivity, fast response and recovery property and excellent gas selectivity, which can also be used in harsh environments. Herein, we design and fabricate the hierarchically porous SiC@Pd hollow micro/nanofibers via electrospinning and polymer-derived ceramics (PDC) route. The effect of the composition, morphology and hierarchical pore structure of the obtained fibers on the gas-sensing properties will be detailed studied. Control of hierarchical pore structure for the resulting micro/nanofibers and the synthesis of Pd nanoparticles on SiC fibers are particularly investigated. Fundaments as following are preliminarily studied: (1) the mechanism of the structure and size effect for hierarchical pores on the response and recovery property; (2) the effect of SiCO phase, SiC micro-crystalline and carbon on the characters of amorphous semiconductors and the selectivity of gas sensing; (3) the effect of double coupling mechanism between Pd and amorphous SiC on the sensitivity and selectivity of gas sensing. Simultaneously, this item provides theoretical and practical guidance to the basic researches and fabrication of functional ultrathin ceramic fibers, high-temperature micro-sensors and micro-electromechanical system (MEMS).

能在极端环境下服役的氢气传感器在航空航天、核工业等军事领域的需求日益迫切。本项目在现有先驱体转化陶瓷纤维研究基础上，以能在极端条件下使用，且具备高灵敏度、快速响应和恢复，特别是有良好氢气选择性的传感材料的制备及相关科学问题为研究目标，采用静电纺丝和先驱体转化技术，设计和制备分级孔结构的SiC@Pd微纳中空纤维。系统研究纤维形貌、组成和分级孔结构模式及分布对气敏性能的影响。突破分级孔结构模式、孔的大小及分布、Pd的形成与分散调控等技术关键。初步探明纤维分级孔结构模式与孔尺寸效应对响应恢复的影响机制，纤维组成（SiCO相、SiC微晶和碳）对无定形半导体特性及其对气敏选择性的影响机制，和Pd与SiC半导体的耦合效应及对敏感性和气敏选择性的影响机制等基本科学问题。本课题对新型微纳陶瓷纤维的设计和制备，乃至对高温微型传感器及其微机电的开发和应用研究，均有较强理论指导意义和实际应用价值。

制备能在极端环境下服役，且具备高灵敏度、快速响应和恢复，有良好氢气选择性的传感材料是航空航天、核工业等军事领域亟待突破的关键技术。本项目已完成项目所有研究内容，成功制备出一种在极端条件下使用的高性能非氧化物分级孔SiC@Pd微纳中空纤维。通过对先驱体溶液的设计与调控、改变静电纺丝工艺，以控制纤维形貌与纤维大孔数量及分布；调控纤维不熔化与纤维无机化进程，调整Pd的引入工艺及研究Pd的分布方式，研究SiC@Pd微纳中空纤维的组成和结构并进行性能表征，总体剖析了纤维组成结构与气敏性能的相关性及其机制，特别是在500 oC高温条件下气敏性能的影响规律，阐释了纤维的结构和形成的肖特基结效应对气敏性能的影响机制。有关本项目的研究内容和研究成果，已在Applied Catalysis B: Environmental, ACS Applied Materials & Interfaces, Sensors & Actuators B: Chemical, Applied Surface Science, Chemical Engineering Journal和Journal of Materials Chemistry C等期刊上共计发表SCI论文26篇，申请国家发明专利6项，其中3项已授权。培养博士生4名，硕士研究生3名。培养的学生1人获评全国“青年托举人才工程”称号、1人获全军优秀博士学位论文、1人获全军优秀硕士学位论文。本项目制备SiC@Pd微纳中空纤维不仅制备方法简单，且设备成本低廉，在未来也具有规模化生产的前景。尽管目前还未进行成果转化，但SiC@Pd微纳中空纤维表现出的优异气敏性能使得其在航空航天、核能发电、汽车和化工等高温领域具有广阔的应用前景。