金属硫属化合物复合凝胶的制备及其自支撑电催化剂的性能研究

To achieve a ‘hydrogen economy’ society, we need to develop electrocatalyst with high efficiency and low cost. As a family of earth abundant materials, metal chalcogenide nanomaterials show great promise in electrocatalysis, due to their high thermal stability and high catalytic activity. It is an effective method to enhance the electrocatalytic activity of electrocatalyst by compounding with another kind of electrocatalyst. Hence, the electrocatalytic activity of metal chalcogenide can be efficiently improved by compounding with other high performance electrocatalysts. Conventional electrocatalysts are usually in the form of fine powders. It is necessary for them to be fabricated into electrodes to be used in realistic electrochemical devices. However, the conventional process for fabrication of electrodes may have a negative impact on the performance of electrocatalyst. Therefore, it has a very realistic significance to develop strategies for synthesis of self-supported electrocatalyst. Gel materials are widely used as electrocatalysts because of their many merits, like character of self-supported, controllable structures and large specific surface areas. In this, we aim to develop methods for controllable synthesis of metal chalcogenide based compound gels in this project. Then, we plan to study the structure-activity relationship between the compositions, structures and electrocatalytic activity of the compound gels. At last, we also plan to study the synergy mechanism between each components of the compound gels.

高效、廉价的非贵金属电催化剂的开发对于“氢经济”的实现至关重要。金属硫属化合物纳米材料具有热稳定性好、储量丰富、电催化性能优异等优点，是非常有应用前景的电催化剂材料。材料的复合是提升电催化性能的有效手段，金属硫属化合物与其它高性能电催化材料复合将有效提升其催化性能。传统的电催化剂一般均以粉体的形式存在，在将其用于实际的电化学器件之前，必须将其制成电极，而传统的电极的制备过程往往可能会对电催化剂的催化性能产生负面的影响。因此，发展自支撑电催化剂的制备技术有着重要的现实意义。凝胶材料具有自支撑、结构可控、比表面大等诸多优点，在电催化领域应用前景广泛。基于此，本项目旨在发展基于金属硫属化合物的复合凝胶的可控制备技术，探明复合凝胶的结构、组分与其电催化性能之间的构效关系，探究复合凝胶中各组分之间的协同机制。

高效、低成本的电催化剂的开发对于“氢经济”的实现至关重要。目前，碱性水电解（AWE）制氢技术作为成熟的电解水制氢技术在市场上占据着主导地位。在碱性条件下，可以使用非贵金属催化剂，因而AWE制氢技术的催化剂成本较低。然而，我们仍然需要开发催化性能更好、成本更低的非贵金属电催化剂以进一步降低AWE制氢技术的成本。金属硫属化合物具有热稳定性好、储量丰富、电催化性能好等优点，是AWE制氢技术理想的电催化剂选择。材料的复合是提升电催化性能的有效手段，金属硫属化合物与其它高性能电催化材料复合将有效提升其催化性能。凝胶材料具有自支撑、结构可控、比表面大等诸多优点，在电催化领域应用前景广泛。基于此，本项目发展了一种金属硫属化合物/碳复合凝胶的可控制备技术，成功的制备了由CoSeTe合金纳米颗粒与氮掺杂碳纳米纤维复合而成的复合凝胶，并研究了其电催化性能。.与AWE制氢技术相比，质子交换膜水电解（PEMWE）制氢技术具有诸多的优点，比如紧凑的系统设计、更快的系统响应、更低的欧姆损失、更少的副反应、更高的电压效率以及更高气体纯度等。然而，目前来说，PEMWE制氢技术所使用的阳极催化剂为铱基催化剂，成本高昂、且资源稀少。与Ir相比，Ru基催化剂具有成本低、催化活性高等优点，是PEMWE制氢技术潜在的电催化剂选择。基于此，本项目研制了一种能在酸性条件下高效催化析氧反应（OER）的电催化剂。以碲纳米线为模板，成功的合成了一种兼具高催化活性以及优良催化稳定性的酸性OER催化剂，即Te掺杂的RuO2（Te-RuO2）多孔纳米管。Te-RuO2多孔纳米管仅需171 mV的过电势即可达到10 mA/cm2的电流密度，远优于商业RuO2催化剂。实验结果以及理论计算表明碲元素的掺入，明显降低了RuO2催化OER过程中决速步的反应能垒，极大的提升了RuO2的催化活性。