Designing Non-Precious Metal M–N/C Electrocatalysts for Alkaline Fuel Cells

Abstract

Anion exchange membrane fuel cells (AEMFCs) incorporating solid alkaline electrolytes have received increasing attention during the past few years. In particular, the higher oxygen reduction reaction (ORR) activity and enhanced durability of low-cost nonprecious metal catalysts (NPMCs) in alkaline media than in acidic media have prompted the current surge of interest in AEMFC as an economically viable energy conversion device. In this context, a wide range of NPMCs have been investigated, and Fe＆minus;N/C catalysts have emerged as the most promising ORR catalysts. Recently, we developed a general design strategy based on ＆ldquo;silica-protective-layer-assisted＆rdquo; method that can preferentially generate ORR-active Fe＆ndash;Nx sites towards highly efficient Fe＆ndash;N/C electrocatalysts. The prepared Fe＆ndash;N/C catalysts showed excellent ORR activity in alkaline and acidic electrolytes. Importantly, an AEMFC employing the prepared Fe＆ndash;N/C catalyst as the cathode exhibited record high current and power densities among NPMC-based AEMFCs. The catalyst showed excellent current density when used as the cathode for acidic proton exchange membrane fuel cell.