Ultrafine IrMnO<sub><i>x</i></sub> Nanocluster Decorated Amorphous PdS Nanowires as Efficient Electrocatalysts for High C1 Selectivity in the Alkaline Ethanol Oxidation Reaction
Qianlin Ju, Tao Chen, Qianhui Xie, Manli Wang, Kaige Zhao, Tong Liu, Liang Fu, Haozhi Wang, Zelin Chen, Changjiu Li, Yida Deng
Abstract
As a novel electrochemical energy conversion device, direct ethanol fuel cells are currently encountering two significant challenges: CO poisoning and the difficulty of C–C bond cleavage in ethanol. In this work, an amorphous PdS nanowires/ultrafine IrMnO x bimetallic oxides (denoted as a-PdS/IrMnO x NWs) catalyst with abundant oxide/metal (crystalline/amorphous) inverse heterogeneous interfaces was synthesized via a hydrothermal process succeeded by a nonthermal air-plasma treatment. This unique interfacial electronic structure along with the incorporation of oxyphilic metal has resulted in a significant enhancement in the electrocatalytic performance of a-PdS/IrMnO x NWs toward the ethanol oxidation reaction, achieving current densities of 12.45 mA·cm –2 and 3.68 A·mg Pd –1 . Moreover, the C1 pathway selectivity for ethanol oxidation has been elevated to 47%, exceeding that of other as-prepared Pd-based counterparts and commercial Pd/C catalysts. Density functional theory calculations have validated the findings that the decoration of IrMn species onto the amorphous PdS surface has induced a charge redistribution in the interface region. The redistribution of surface charges on the a-PdS/IrMnO x NWs catalyst results in a significant decrease in the activation energy required for C–C bond cleavage and a notable weakening of the CO binding strength at the Pd active sites. Consequently, it enhanced both the EOR C1 pathway selectivity and CO poisoning resistance to the a-PdS/IrMnO x NWs catalyst.