介稳相非贵金属基合金纳米材料的可控制备及电催化性能研究

Electrocatalysis in energy field deliver promising prospects when it comes to the contemporary jeopardized environmental issues. Hence, developing the high-performance and low-cost catalysts with low concentration of or non- noble metal is mandatory. Non-noble metal based alloy catalysts stand out from the crowed candidates. Compared with the ones with stable phases, metastable non-noble metal based alloy nanomaterials own relative high Gibbs energy, easily formed electrocatalytic active surface and increased numbers of active sites exposed by the controlled morphology, bringing new opportunities, yet challenges for the development of high-performance catalysts. In the synthetic process of metastable alloy, extra energy from outside environment is necessary for stabilizing the metastable phase and the phases of metastable alloys are quite complex. Therefore, we will make great efforts on exploring the controlled fabrications of metastable non-noble metal based alloy nanomaterials. For example, high temperature, high pressure or laser irradiation will be assisted in the synthetic process. In addition, the thermodynamic instability induce the transformation from the metastable phase into the stable one. Based on this property, our proposal will carry out several pathways, the ion doped strategy, support strategy and so on, to improve the catalytic stability of metastable non-noble metal catalysts. Combined with our previous work about the syntheses and electrocatalytic applications of metastable materials, we propose the application titled “Controlled Syntheses and Electrocatalytic Studies of Metastable Non-noble Metal Based Alloy Nanomaterials”, in order to pursue the breakthrough in performances of non-noble metal based alloys for electrocatalytic reactions.

随着环境问题的日益严峻，与能源相关的电催化展现出诱人的应用前景，使得开发低含量，甚至零贵金属参与的高性能低成本电催化剂迫在眉睫。非贵金属基合金催化剂在众多候选者中脱颖而出。相比于稳定相材料，介稳相非贵金属基合金纳米材料的吉布斯自由能更高，易产生电催化活性表面，且可通过形貌调控暴露更多催化活性位点。这为高性能催化剂的开发带来新的契机，也充满挑战。介稳相合金在合成中需外界施加能量使产物稳定在介稳相且其物相较复杂。因此我们着力探索介稳相非贵金属基合金纳米材料的可控制备。例如在合成中施加高温、高压、激光照射等辅助。同时介稳相的热力学不稳定性决定其向稳定相的转变。为此，本项目拟采取离子掺杂法、载体法等策略提高该类催化剂的稳定性。本申请人结合自己在介稳相材料合成及电催化应用的前期工作，提出“介稳相非贵金属基合金纳米材料的可控制备及电催化性能研究”的申请项目，力争实现非贵金属催化剂在电催化中的性能突破。

发展了高能前驱体耦合法制备了介稳相六方相镍及其衍生物。在介稳相镍钴合金中构筑同质多晶界面。这一特殊的界面结构提高了介稳相向稳定相转变的相变能垒，有效地保护介稳相六方相内核，提高介稳相催化剂的稳定性。同时，在界面处强的相互作用有效降低催化剂的氢吸附能，从而有利于电催化析氢。在这些工作的基础上进一步发展了介稳相材料的种类。首次开发熔碱力化学方法。利用该方法在强碱环境中，对原料三氯化铱进行高温研磨，得到介稳相二维1T相氧化铱纳米片。球差电镜和同步辐射吸收表征发现，氧化铱纳米片是1T相，层与层之间是AA堆积，明显不同于稳定相金红石相氧化铱。1T相氧化铱在电流密度10 mA cm-2下的过电位仅为197 mV。并在1.50 V vs. RHE下实现4.2 sUPD-1（3.0 sBET-1）的高转换频率。此外，在实际质子交换膜装置中，1T相氧化铱在250 mA cmgeo-2的高电流密度下，经过126小时的稳定性测试后未表现出明显的活性衰减。.以通讯作者发表相关SCI论文16篇。