Tri-Metal-based Hollow Nanorods-On-Microrod Arrays as Efficient Water Splitting Electrocatalysts

Abstract Constructing ordered hierarchical porous electrocatalysts while maintaining their high efficiency and stability for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desirable but still remains challenging. Herein, hierarchical tri-metal-based hollow nano/micro rod-on-rod array structures, including hydroxides and phosphates, are vertically grown on Cu foam by the cation-exchanging and anion exchanging approaches. Such ordered porous architecture, providing multi metal center, regular interconnection of macropore channel, large electrochemical surface area, small charge-transfer resistance, efficient mass transport and electron transfer for overall water splitting in alkaline media. These obtained hydroxide OER catalysts (CoMn LDH@Cu(OH)2/CF) and phosphide HER catalysts (CoMnP@Cu3P/CF) exhibited low onset potential, low Tafel slope, and prominent durability. Such excellent performance, ordered porous structure and simple preparation methods indicate that this study provides a new strategy for assembling promising catalysts for water splitting and other applications.