自偏压光电催化资源化处理H2S的性能与反应机制

Hydrogen sulfide is a typical dangerous contaminant and it can be widely found in waste treatment and byproduct from industry. Therefore, the safe treatment and resource recovery for H2S is very valuable. Photoelectrocatalytic method is approved to be feasible way for splitting H2S into H2 and S; however, as for now, it has some drawbacks including energy cost from external bias, poor stability and low efficiency, resulting in the limitation for treating H2S efficiently. This project proposed a heterojuction photoanode consisted of a highly ordered TNAs and 2D layered MoS2. As expected, the photocathode shows a 3D morphology with larger surface area, faster electron transportation and good stability. Based on Cu2O nanowires, photocathode are prepared by growing ZnO nanowires on the top to form heterojuction, which also shows larger surface area, faster electron transportation and good stability. Based on proposed photoanode and photocathode, the self-bias visible respond photoelectrocataltyic recovery of H2S system is established. This project will also investigate properties of both photoelectrodes as well as their performance and mechanism in the system for H2S recovery.

硫化氢是污染处理和工业副产物中常见的有毒有害污染物，其资源化安全处置有重要意义。利用太阳光光电催化技术可以将硫化氢资源化分解为单质硫和氢气，但是现有光电催化技术需要外加偏电压而耗能，同时光电极稳定性差、效率低，限制了应用。项目以结构高度有序、光生电荷迁移性能好的金属钛基TiO2纳米管阵列（TNA）为光阳极基底材料，利用TNA与具有二维层状结构的MoS2构成异质结，形成具有三维结构、内电场结构、比表面积大、稳定性好的MoS2/TNA/Ti光阳极材料；以金属铜基Cu2O纳米线阵列为光阴极基底材料，利用ZnO与Cu2O形成的异质结，具有多支纳米线结构、内电场结构、比表面积大、稳定性好的特点，制备ZnO/Cu2O/Cu光阴极材料；在此基础上，建立可见光响应的、具有自偏压功能的、高效光电催化资源化安全处置H2S的系统与方法，并研究光阳极、光阴极以及反应系统分解硫化氢产氢、产硫的相关性能与微观机制。

硫化氢（H2S）是一种有毒有害的废气，广泛存在于厌氧废水处理过程（硫酸盐还原）中，也是石油化工、煤炭化工的副产物。硫化氢还能腐蚀工业设备。硫化氢的安全处置和资源化利用具有重要的意义。氢气既是清洁能源，和单质硫又都是重要的化工原料，因此将H2S分解为S单质和氢气的资源化途径最引人关注。传统分解H2S气体的工艺方法中，所涉及到的反应装置极其复杂，能耗高，处理成本较大。光催化燃料电池是一种新型的废弃物资源化技术，可以克服传统处理H2S气体方法中的多种难题，本研究以制备新型稳定可见光响应的光阳极半导体材料和光阴极半导体材料为基础，我们首次提出了自驱动处理硫化氢气体的光催化系统。我们首先制备了具有可见光吸收和优异的光电化学性能的WO3光阳极和铂修饰硅光阴极（Pt/SiPVC），然后由以上电极构建了自偏压驱动的光电催化系统。基于以上体系，我们引入了I-/I3-这个特殊的循环氧化还原反应电子对，来促进S2-向单质硫的转化，实现了H2S的完全分解，产氢和产硫效率分别为0.0131mmol h-1 cm-2和0.0135mmol h-1 cm-2，发电功率达到0.11 mW cm-2。由于氢气不易存储，我们进一步发展了气体扩散电极，在阴极产生双氧水，总产率分别达到了6.816 mg h-1和0.80mmol/L/h。基于光催化燃料电池的H2S处理技术，可以为H2S的安全处置和资源化利用提供新的可持续发展方向。