Ternary Pt9RhFex Nanoscale Alloys as Highly Efficient Catalysts with Enhanced Activity and Excellent CO-Poisoning Tolerance for Ethanol Oxidation

Peng Wang; Shibin Yin; Ying Wen; Zhiqun Tian; Ningzhang Wang; Julian Key; Shuangbao Wang; Pei Kang Shen

doi:10.1021/acsami.6b14947

Ternary Pt₉RhFe_x Nanoscale Alloys as Highly Efficient Catalysts with Enhanced Activity and Excellent CO-Poisoning Tolerance for Ethanol Oxidation

ACS Appl Mater Interfaces. 2017 Mar 22;9(11):9584-9591. doi: 10.1021/acsami.6b14947. Epub 2017 Mar 13.

Authors

Peng Wang^{1

2}, Shibin Yin¹, Ying Wen¹, Zhiqun Tian¹, Ningzhang Wang³, Julian Key¹, Shuangbao Wang¹, Pei Kang Shen¹

Affiliations

¹ Guangxi Key Laboratory of Electrochemical Energy Materials, Collaborative Innovation Center of Renewable Energy Materials (CICREM), Guangxi University , Nanning 530004, China.
² State Key Laboratory of Processing for Non-ferrous Metal and Featured Materials, Guangxi University , Nanning 530004, China.
³ School of Computer, Electronics and Information, Guangxi University , Nanning 530004, China.

PMID: 28195459
DOI: 10.1021/acsami.6b14947

Abstract

To address the problems of high cost and poor stability of anode catalysts in direct ethanol fuel cells (DEFCs), ternary nanoparticles Pt₉RhFe_x (x = 1, 3, 5, 7, and 9) supported on carbon powders (XC-72R) have been synthesized via a facile method involving reduction by sodium borohydride followed by thermal annealing in N₂ at ambient pressure. The catalysts are physically characterized by X-ray diffraction, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy, and their catalytic performance for the ethanol oxidation reaction (EOR) is evaluated by cyclic and linear scan voltammetry, CO-stripping voltammograms, and chronopotentiometry. All the Pt₉RhFe_x/C catalysts of different atomic ratios produce high EOR catalytic activity. The catalyst of atomic ratio composition 9:1:3 (Pt/Rh/Fe) has the highest activity and excellent CO-poisoning tolerance. Moreover, the enhanced EOR catalytic activity on Pt₉RhFe₃/C when compared to Pt₉Rh/C, Pt₃Fe/C, and Pt/C clearly demonstrates the presence of Fe improves catalytic performance. Notably, the onset potential for CO oxidation on Pt₉RhFe₃/C (0.271 V) is ∼55, 75, and 191 mV more negative than on Pt₉Rh/C (0.326 V), Pt₃Fe/C (0.346 V), and Pt/C (0.462 V), respectively, which implies the presence of Fe atoms dramatically improves CO-poisoning tolerance. Meanwhile, compared to the commercial PtRu/C catalyst, the peak potential on Pt₉RhFe₃/C for CO oxidation was just slightly changed after several thousand cycles, which shows high stability against the potential cycling. The possible mechanism by which Fe and Rh atoms facilitate the observed enhanced performance is also considered herein, and we conclude Pt₉RhFe₃/C offers a promising anode catalyst for direct ethanol fuel cells.

Keywords: CO-poisoning tolerance; Pt9RhFex alloys; anode catalysts; ethanol oxidation; ternary nanoparticles.