层状钴钌氢氧化物纳米锥的合成及电催化性能研究

Synthesis and Electrocatalytic Properties of Layered Cobalt-Ruthenium Hydroxide Nanocones

摘要: 层状钴基氢氧化物由于其丰富的地球资源、较低的动力学过电位和优越的稳定性，是一种很有前途的电催化析氧反应催化剂。然而，层状钴基氢氧化物的水解动力学缓慢，在碱性环境下析氢反应的活性较差。形貌控制在催化剂的设计中也是一种很有效的策略。纳米锥因为其独特的中空结构，可能具有特殊的电子、机械和场发射特性。本文提出了利用共沉淀方法，通过钌部分取代钴，将钌掺入氢氧化钴纳米锥的晶格中，可以显著提高材料的析氧性能和析氢性能，而不影响纳米锥的形貌。在10 mA•cm₋₂的电流密度下，析氧过电势仅为260 mV，优于其他钴基氢氧化物纳米材料。将钌原子引入氢氧化钴纳米锥的晶格中可以有效降低电催化过程中的能量势垒，OER和HER过电势分别降低了99 mV和286 mV，从而加速水解反应动力学。

Abstract: Layered cobalt (Co) hydroxide is a promising catalyst for oxygen evolution reaction (OER) due to its abundant earth resources, low kinetic overpotential and superior stability. However, the hydrolysis kinetics of layered Co hydroxide is slow and the activity of hydrogen evolution reaction (HER) is poor in alkaline environment. Morphology control is also an effective strategy in catalyst design. Nanocones may have special electronic, mechanical and field emission properties because of their unique hollow structure. In this paper, we present a coprecipitation method, in which ruthenium (Ru) is partially substituted for Co and Ru is doped into the crystal lattice of Co hydroxide nanocones, which can significantly improve the OER and HER properties of the materials without affecting the morphology of the nanocones. At the current density of 10 mA•cm₋₂, the OER overpotential is only 260 mV, which is better than other Co-based hydroxide nanomaterials. Introducing Ru atoms into the crystal lattice of Co hydroxide nanocones can reduce the energy barrier in the electrocatalytic process effectively, and the OER and HER overpotential decreased by 99 mV and 286 mV respectively, thus accelerating the hydrolysis reaction kinetics.