微流体光催化燃料电池用于废水资源化的机理及动力学研究

In industrial wastewater treatment, heavy metals and organic matters must be removed before disposal as they are highly toxic and carcinogenic. Recent research indicates that microfluidic photocatalytic fuel cell (MFPC) has the promise to achieve collaborative treatment of heavy metals and organic matters in wastewater. The processes could also generate electricity and recover useful metals, i.e. "multigeneration." It is anticipated that the MPFC technology will be far more energy-efficient and cost-effective than the conventional wastewater treatment methods. In this proposal, computational modeling and experimental study will be conducted for the MPFC collaborative treatment of wastewater. The main objectives are: (1) to synthesize BiVO4/TiO2 anode and Ag/graphene cathode and to determine what properties the anode photocatalyst and cathode electrocatalyst should possess to achieve high MPFC kinetics and (2) to find out how modified MPFC architecture can enhance the species transport and resultant MFC kinetics. Then, one will be able to greatly improve the synergistic effects on the MPFC wastewater treatment and multigeneration. It is noted that besides wastewater treatment, the new knowledge gained here will enable further development of MPFC technologies for other challenges in field of energy and environment, e.g. solar production of clean fuel, carbon capture, storage and conversion, and seawater desalination.

能源危机和环境污染已然成为我国面临的两大严重问题。微流体光催化燃料电池（MPFC）能够实现废水中化学能的再利用，是一种清洁高效的废水资源化技术，对解决水污染问题和缓解能源短缺具有重大意义。本申请项目拟从实验和模拟计算两方面进行MPFC的设计工作：（1）构建BiVO4/TiO2纳米片阳极和Ag/Graphene阴极，考察阳极材料光催化氧化有机废水、阴极材料电化学还原重金属离子的协同作用，阐明催化反应机理，探索复合污染物的综合处理和能源回收利用的可行性；（2）建立有限单元法模型，对MPFC内部微米尺度下的物质传输、纳米尺度下的材料表面化学反应动力学进行模拟分析，并分析不同操作条件对MPFC的电化学能量转换效率的影响规律。本项目的实施将为MPFC的设计和开发提供重要的科学信息和理论基础，深化人们对复合污染物分子协同处理工作原理的进一步认识，对环境污染物的去除和能源的回收再利用具有重要的学术价值。

随着经济的飞速发展，社会对能源的需求日益扩大，对工业废水的无害化处理也提出了更高的要求。光催化燃料电池在燃料电池中引入半导体光催化材料作为电极，实现了有机污染物高效降解和同步对外产电的双重功能，在废水无害化与资源化利用方面具有潜在的应用价值。针对PFC系统优化，从光催化阳极和电催化阴极性能调控两方面取得了如下主要研究进展：. （1）光催化阳极性能调控。通过微波辅助水热法制备了NiFe-LDH/BiVO4异质结复合材料作为PFC光阳极。NiFe-LDH/BiVO4异质结不仅有效增强了太阳能收集，而且提高了光生电荷载流子的传输效率。利用NiFe-LDH/BiVO4光阳极和Cu2O/Cu光阴极构建了双光电极PFC。所构建的PFC可以在AM 1.5G照射下由内部偏置驱动，双光电极PFC系统的Jsc增加至300 μA cm−2后逐渐下降到100 μA cm−2。以葡萄糖为模拟有机基质，0.5 M Na2SO4为电解质，双光电极PFC系统的Voc、Jsc、Pmax和FF，分别为0.647 V，0.196 mA cm−2，74 μW cm−2和58.4%。. （2）电催化阴极性能调控。（a）通过化学气相沉积和一步热解法制备了SCNCs、FeNSCs和Co/N–CNFs电催化剂，得益于杂原子掺杂和金属颗粒沉积，催化剂表现出优异的氧还原性能，1600 rpm转速时极限扩散电流密度、起始电位、半波电位、稳定性等氧还原反应特征参数均优于商业Pt/C催化剂。（b）利用简单溶剂热和高温裂解法制备Co-Mo-SA/NC催化剂，其均匀分散着Co–Mo单原子金属对，表现出优异的电催化还原N2产NH3性能，NH3产率和FE分别为37.73 μg h−1 mgcat−1和23.18 %（−0.1 V vs. RHE），并且表现出优异的稳定性。