In-situ oxidation of Palladium-Iridium nanoalloy anchored on Nitrogen-doped graphene as an efficient catalyst for methanol electrooxidation

Junhao Shu; Ruxia Li; Zhuoming Lian; Wei Zhang; Ruifa Jin; Honglei Yang; Shuwen Li

doi:10.1016/j.jcis.2021.07.056

In-situ oxidation of Palladium-Iridium nanoalloy anchored on Nitrogen-doped graphene as an efficient catalyst for methanol electrooxidation

J Colloid Interface Sci. 2022 Jan:605:44-53. doi: 10.1016/j.jcis.2021.07.056. Epub 2021 Jul 15.

Authors

Junhao Shu¹, Ruxia Li¹, Zhuoming Lian¹, Wei Zhang¹, Ruifa Jin², Honglei Yang³, Shuwen Li⁴

Affiliations

¹ State Key Laboratory of Applied Organic Chemistry (SKLAOC), Gansu Provincial Engineering Laboratory for Chemical Catalysis, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China.
² Inner Mongolia Key Laboratory of Photoelectric Functional Materials, College of Chemistry and Life Sciences, Chifeng University, Chifeng 024000, China.
³ State Key Laboratory of Applied Organic Chemistry (SKLAOC), Gansu Provincial Engineering Laboratory for Chemical Catalysis, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China. Electronic address: yanghl@lzu.edu.cn.
⁴ State Key Laboratory of Applied Organic Chemistry (SKLAOC), Gansu Provincial Engineering Laboratory for Chemical Catalysis, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China. Electronic address: lishw@lzu.edu.cn.

PMID: 34303923
DOI: 10.1016/j.jcis.2021.07.056

Abstract

Palladium (Pd)-based materials have been widely used as catalysts for the methanol oxidation reaction (MOR). Unfortunately, the catalytic activity was limited by structure, carbon monoxide intermediates (CO_ads) tolerance and stability. It was currently difficult to be used in large-scale commercial production. Herein, to further improve their electrocatalytic activity, a facile oxidation method to achieve in-situ oxidation of palladium-iridium (PdIr) alloy on nitrogen-doped graphene (NGS) is used, which is named as Pd-Ir-O/NGS. The new catalyst exhibits remarkable MOR activity (1374.8 mA mg^-1), CO_ads tolerance (the onset oxidation potential reach 0.725 V) and stability (the current density retention rate after 500 cycles of cyclic voltammetry is 44.9%). As a catalyst for MOR, the Pd-Ir-O/NGS has more outstanding electrocatalytic performance compared with commercial Pd/C and other counterparts. The mechanism study shows that the excellent catalytic performance is attributed to (1) the synergistic electronic effect of Pd-Ir-O due to the introduction of Ir and O, (2) the insertion of O into PdIr alloy that kinetically accelerated the oxidation of poisoning methoxy intermediates and (3) the vital roles of unique three-dimensional (3D) structure of NGS with abundant nitrogen atoms. Our findings herald a new paradigm for the modification of palladium-based materials for MOR and provide an alternative design principle for novel 3D carbon-based material for various application.

Keywords: In-situ oxidation; Methanol oxidation reaction; Nitrogen-doped graphene; Palladium–iridium alloy; Three-dimensional structure.