Template-Based Synthesis of Porous and Wrinkled Pt-Supported MXene for Enhanced Bifunctional Electrocatalysis - ORR and HER

Abstract

This study proposes a novel strategy to develop a platinum-supported, highly porous Mxene (Pt/PMx) catalyst via a “template-based transformation” approach and evaluates its bifunctional electrocatalytic properties for oxygen reduction (ORR) and hydrogen evolution reactions (HER). The strategy introduces defects into the nitrogen Mxene sheets, enhancing their surface area and porosity. The synthesized PMx effectively mitigates the restacking of Mxene sheets and facilitates the uniform dispersion of ultrasmall platinum nanoparticles across the surface. The Pt/PMx catalyst exhibits excellent ORR activity, achieving an onset potential of Eon = 0.93 V (Eon for Pt/C = 0.94 V) in an acidic medium and Eon = 0.94 V (Eon for Pt/C = 0.92 V) in an alkaline medium, along with superior chronoamperometric stability with 40,000 sec. Comprehensive evaluations of intrinsic parameters, including active surface area, mass activity, CO poisoning tolerance, and durability via accelerated degradation tests, confirms the robustness of the electrocatalyst support. The significant interaction between Pt nanoparticles and the support enhances H+ adsorption and charge transport thereafter HER activity, attributed to the improved porosity and conductivity of the support. The strong interaction between Pt and PMx was found to be the key for excellent stability towards ORR (20,000 potential cycles) and HER (~40 hr). This synthesis strategy provides a unique and novel pathway for designing highly porous, conductive, and hydrophilic Pt-based catalyst supports for improved ORR and HER performance.