In Situ Exsolved Ru─Cu Nano‐Heterostructures on CeO ₂ ‐Based Anode Catalytic Layer for High‐Performance and Coking‐Tolerant Direct Methanol Protonic Ceramic Fuel Cells

ABSTRACT

Direct methanol protonic ceramic fuel cells (PCFCs) offer significant advantages in fuel storage, transportation, and volumetric energy density compared with gaseous hydrogen. However, conventional Ni‐cermet anodes suffer from sluggish methanol reforming kinetics and severe coking at intermediate temperatures. Herein, we develop a novel Ce _0.9 Ru _0.05 Cu _0.05 O _2‐δ (CRCO) anode catalytic layer (ACL) on a Ni‐BaZr _0.4 Ce _0.4 Y _0.1 Yb _0.1 O _3‐δ (Ni‐BZCYYb) anode. Under operating conditions, in situ exsolution yields stable nano‐heterostructures featuring metallic Ru‐Cu‐Ni nanoparticles anchored on the CeO ₂ framework. A Ni‐BZCYYb anode‐supported single cell incorporating the formed catalytic layer delivers a peak power density of 1.05 W cm ⁻² and maintains a stable operation for over 100 h at 0.3 A cm ⁻² at 650°C when fueled with 35% humidified CH ₃ OH. The improved electrochemical performance and coking tolerance can be ascribed to the in situ formed Ru‐Cu‐Ni and ceria oxide heterointerfaces within the ACL and the Ni‐BZCYYb anode, which effectively catalyze methanol decomposition and steam reforming, as corroborated by Raman spectroscopy, exhaust gas analysis, and other post‐operation characterization results. This work demonstrates an effective interfacial engineering strategy for high‐performance, durable direct methanol PCFCs.