溶剂热制备镍铁硫化物及其高效电催化析氢性能的研究

Solvothermal Preparation of Nickel-Iron Sulfides and Their Efficient Electrocatalytic Hydrogen Evolution Properties

摘要:

随着科学技术的迅猛发展，能源消耗越来越大，鉴于人类当前所依赖的化石燃料终会消失殆尽，因此开发新型能源成为重中之重，而在新能源领域中电解水制氢被寄予厚望。电解水产生的氢气和氧气分别经由析氢反应（HER）和析氧反应（OER）而生成，这就需要高效且稳定的电催化剂。目前，IrO₂/RuO₂电催化剂分别在HER和OER过程中表现出基准的催化活性。然而，贵金属的高额成本及丰度过低，已阻碍了其推广应用。所以，开发高效的水裂解电催化剂至关重要。基于过渡金属(如Fe、Co、Ni、Mo和原子Pt)电催化水解反应（HER/OER）催化剂的研发成果，发现过渡金属催化剂均显示出良好的催化活性和耐久性，并且双过渡金属成分催化剂的催化性能往往优于单过渡金属成分的催化剂，尤其是过渡金属硫化物展现出优异的析氢效果。催化剂常见的制备方法包括电沉积法、溶剂热法、化学腐蚀法和静电纺丝法等。为了结合双过渡金属和金属硫化的优势，通过溶剂热法制备了镍铁硫化物（NiFeS）催化剂，该催化剂为表面褶皱的纳米块状结构，该结构使催化剂拥有更多的活性位点和更大的电化学面积。其中，NiFeS-2催化剂还拥有高的电导率，从而使其拥有良好的电催化性能。在碱性电解液（1 mol·L^-1 KOH）中，NiFeS-2的过电位为125 mV（电流密度为10 mA?cm^-2）。本研究为设计及制备低成本且稳定高效的双过渡金属基硫化物电催化剂提供了新的思路。

Abstract:

With increasing energy demands and the inevitable depletion of fossil fuels， developing new energy sources is crucial. Water electrolysis for hydrogen production is particularly promising. This process， which generates hydrogen and oxygen via the hydrogen evolution reaction （HER） and oxygen evolution reaction （OER）， necessitates efficient and stable electrocatalysts. Currently， IrO₂/RuO₂ electrocatalysts exhibit benchmark catalytic activities for HER and OER， respectively. However， the high cost and scarcity of these precious metals pose significant challenges to their widespread application. Thus， developing efficient and affordable electrocatalysts for water splitting is essential. In recent decades， significant research has focused on alternative HER/OER and water-splitting catalysts based on various transition metals， including Fe， Co， Ni， Mo， and atomic Pt. These have demonstrated promising catalytic activity and durability， with catalysts composed of dual transition metal components often outperforming those with a single component. Some studies have demonstrated that transition metal sulfides exhibit excellent hydrogen evolution capabilities. Common preparation methods include electrodeposition， solvothermal synthesis， chemical etching， and electrospinning. To harness the benefits of dual transition metals and metal sulfides， we synthesized nickel-iron sulfides using a solvothermal method. This approach produced nanoblock NiFeS catalysts with wrinkled surfaces， enhancing their active sites and electrochemical surface area， while also exhibiting high electrical conductivity. These features contribute to their effective electrocatalytic performance. In an alkaline electrolyte （1 mol·L^-1 KOH）， NiFeS-2 achieves an overpotential of 125 mV at a current density of 10 mA·cm^-2. This research offers insights into designing and preparing cost-effective， stable， and efficient double-transition metal sulfide electrocatalysts.