表面活性剂调控铁基氢氧化物电催化剂的微观结构及OER催化性能

Surfactant-Mediated Modulation of the Microstructure and OER Catalytic Performance of Iron-Based Hydroxide Electrocatalysts

摘要: 本研究系统分析表面活性剂对过渡金属铁基金属化合物的微观形貌影响及电解水OER催化活性的影响。采用水热合成法，通过改变表面活性剂的种类及浓度，分别采用阴离子表面活性剂十二烷基磺酸钠(SDS)、非离子表面活性剂聚乙烯吡咯烷酮(PVP)和质子化月桂胺聚氧乙烯醚(1215-质子化)，调控铁基氢氧化物催化剂材料的晶体结构与形貌，并结合XRD、SEM及电化学测试(LSV, EIS, CV)分析物相组成，微观形貌对电催化性能的影响。结果表明，SDS主要通过静电吸附抑制铁基氢氧化物晶体的晶面生长，形成类椭圆层状结构，且诱导(310)晶面优势生长；PVP通过空间位阻效应提升铁基材料结晶度，诱导形成规则棒状及立方体结构；1215 (质子化)则促形成多孔碎片状结构，增大比表面积。同时存在自支撑载体碳纸及表面活性SDS制备的铁基化合物催化剂具有最佳的OER催化活性，其驱动10 mA/cm²电流密度的电位为0.596 V，电荷转移电阻低至1.3 Ω cm²，电化学活性面积为191.8 cm²。本研究揭示了表面活性剂分子结构与金属化合物的作用机制，为高效非贵金属电催化剂的设计提供了理论与实验依据。

Abstract: This study systematically analyzes the effects of surfactants on the microstructure and oxygen evolution reaction (OER) catalytic activity of transition metal iron-based compounds. Using a hydrothermal synthesis method, the crystal structure and morphology of iron-based hydroxide catalyst materials were regulated by varying the type and concentration of surfactants, specifically employing the anionic surfactant sodium dodecyl sulfonate (SDS), the nonionic surfactant polyvinylpyrrolidone (PVP), and protonated laurylamine polyoxyethylene ether (protonated 1215). The effects of phase composition and microstructure on electrocatalytic performance were analyzed using XRD, SEM, and electrochemical measurements (LSV, EIS, CV). The results show that SDS primarily inhibits the growth of specific crystal facets of the iron-based hydroxide through electrostatic adsorption, forming an elliptical layered structure and inducing the preferential growth of the (310) crystal plane. PVP enhances the crystallinity of the iron-based material via steric hindrance, inducing the formation of regular rod-like and cubic structures. Protonated 1215 promotes the formation of a porous fragmented structure, increasing the specific surface area. In the presence of the self-supporting carbon paper substrate, the iron-based compound catalyst prepared with SDS exhibits the best OER catalytic activity, achieving a potential of 0.596 V to drive a current density of 10 mA/cm², a charge transfer resistance as low as 1.3 Ω cm², and an electrochemical active surface area (ECSA) of 191.8 cm². This study elucidates the interaction mechanism between surfactant molecular structures and metal compounds, providing both theoretical and experimental foundations for the design of efficient non-noble metal electrocatalysts.