Xiaotong Zhou¹, Songliang Liu¹*, Huaifang Teng¹, Kun Ma¹, Weixin Miao¹, Xuejing Cui¹, Xin Zhou^2,3* and Luhua Jiang¹*

¹ Electrocatalysis & Nanomaterial Laboratory, College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.

² Interdisciplinary Research Center for Biology and Chemistry, Liaoning Normal University，Dalian，Liaoning，116029, P. R. China.

³ College of Environment and Chemical Engineering, Dalian University, Dalian 116622, P. R. China.

* Corresponding authors:  liusongliang@qust.edu.cn, zhouxin@dlu.edu.cn, luhuajiang@qust.edu.cn

Abstract

Reasonable construction of high activity and selectivity electrocatalysts is crucial to achieve efficient ethanol oxidation reaction (EOR). However, the oxidation of ethanol tends to produce CO specie that poison the active centers of the EOR electrocatalysts. Herein, we developed a unique amorphous CrO_x-protected defect-rich ultrafine Pd nanowires (CrO_x-Pd NWs). On the one hand, the CrO_x layer can act as a protective layer to maintain the structure of the nanowire. On the other hand, it can play the role of OH regulator to optimize the adsorption energy barrier of intermediate species in Pd nanowire, thereby enhancing the ability of the catalyst to resist CO poisoning. The CrO_x-Pd NWs exhibits excellent EOR performance with 3.59 times higher mass activity and 50 mV lower CO electro-oxidation potential than commercial Pd black. The results show that the CrO_x layer promotes the dissociation of H₂O into OH_ads, while the CrO_x transfers electrons to neighboring Pd atoms optimising the electronic configuration of Pd, thus selectively oxidizing ethanol to acetate and preventing the formation of toxic *CO. This work provides an effective strategy for the synthesis of nanowire materials with oxide/metal interfaces and offers new ideas for the design of catalysts that can efficiently drive EOR.

Keywords: Pd nanowires, defect, amorphous CrO_x, electrocatalysts, ethanol oxidation reaction