Quantum confinement-induced anti-electrooxidation of metallic nickel electrocatalysts for hydrogen oxidation
Yuanyuan Zhou, Wei Yuan, Mengting Li, Zhenyang Xie, Xiaoyun Song, Yang Yang, Jian Wang, Li Li, Wei Ding, Wen‐Feng Lin, Zidong Wei
Abstract
Abstract The anion-exchange-membrane fuel cell (AEMFC) is an attractive and cost-effective energy-conversion technology because it can use Earth-abundant and low-cost non-precious metal catalysts. However, non-precious metals used in AEMFCs to catalyse the hydrogen oxidation reaction are prone to self-oxidation, resulting in irreversible failure. Here we show a quantum well-like catalytic structure (QWCS), constructed by atomically confining Ni nanoparticles within a carbon-doped-MoO x /MoO x heterojunction (C-MoO x /MoO x ) that can selectively transfer external electrons from the hydrogen oxidation reaction while remaining itself metallic. Electrons of Ni nanoparticles gain a barrier of 1.11 eV provided by the QWCS leading to Ni stability up to 1.2 V versus the reversible hydrogen electrode (V RHE ) whereas electrons released from the hydrogen oxidation reaction easily cross the barrier by a gating operation of QWCS upon hydrogen adsorption. The QWCS-catalysed AEMFC achieved a high-power density of 486 mW mg Ni −1 and withstood hydrogen starvation operations during shutdown–start cycles, whereas a counterpart AEMFC without QWCS failed in a single cycle.