物理化学学报2020，Vol.36Issue(9)：139-146,8.DOI:10.3866/PKU.WHXB201912049
具有优异甲醇耐受性的Rh掺杂PdCu有序金属间化合物纳米粒子增强氧还原电催化
Rh-Doped PdCu Ordered Intermetallics for Enhanced Oxygen Reduction Electrocatalysis with Superior Methanol Tolerance
摘要
Abstract
Direct methanol fuel cells (DMFCs),as one of the important energy conversion devices,are of great interest in the fields of energy,catalysis and materials.However,the application of DMFCs is presently challenged because of the limited activity and durability of cathode catalysts as well as the poisoning issues caused by methanol permeation to the cathode during operation.Herein,we report a new class of Rh-doped PdCu nanoparticles (NPs) with ordered intermetallic structure for enhancing the activity and durability of the cathode for oxygen reduction reaction (ORR) and achieving superior methanol tolerance.The disordered Rh-doped PdCu NPs can be prepared via a simple wet-chemical method,followed by annealing to convert it to ordered phases.The results of transmission electron microscopy (TEM),scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS),power X-ray diffraction (PXRD) analysis and high resolution TEM (HRTEM) successfully demonstrate the formation of near-spherical NPs with an average size of 6.5 ± 0.5 nm and the conversion of the phase structure.The complete phase transition temperatures of Rh-doped PdCu NPs and PdCu are 500 and 400 ℃,respectively.The molar ratio of Rh/Pd/Cu in the assynthesized Rh-doped PdCu NPs is 5/48/47.Benefitting from Rh doping and the presence of the ordered intermetallic structure,the Rh-doped PdCu intermetallic electrocatalyst achieves the maximum ORR mass activity of 0.96 A·mg-1 at 0.9 V versus reversible hydrogen electrode (RHE) under alkaline conditions-a 7.4-fold enhancement compared to the commercial Pt/C catalyst.For different electrocatalysts,the ORR activities follow the sequence,ordered Rh-doped PdCu intermetallics ＞ ordered PdCu intermetallics ＞ disordered Rh-doped PdCu NPs ＞ disordered PdCu NPs ＞ commercial Pt/C catalyst.In addition,the distinct structure endows the Rh-doped PdCu intermetallics with highly stable ORR durability with unaltered half-wave potential (E1/2) and mass activity after continuous 20000 cycles,which are higher than those of other electrocatalysts.Furthermore,the E1/2 of the Rh-doped PdCu intermetallics decreases by only 5 mV after adding 0.5 mol·L-1 methanol to the electrolyte,while the commercial Pt/C catalyst negatively shifts by 235 mV and a distinct oxidation peak can be observed.The results indicate that the ORR activity of the Rh-doped PdCu intermetallic electrocatalyst can be well maintained even in the presence of poisoning environment.Our results have demonstrated that Rh-doped PdCu NPs with ordered intermetallic structures is a potential electrocatalyst toward the next-generation high-performance DMFCs.关键词
Rh掺杂/有序金属间化合物/纳米颗粒/氧还原/甲醇耐受性Key words
Rh doping/Ordered intermetallics/Nanoparticle/Oxygen reduction/Methanol tolerance分类
化学化工引用本文复制引用
李蒙刚,郭少军,夏仲泓,黄雅荣,陶璐,晁玉广,尹坤,杨文秀,杨微微,于永生..具有优异甲醇耐受性的Rh掺杂PdCu有序金属间化合物纳米粒子增强氧还原电催化[J].物理化学学报,2020,36(9):139-146,8.基金项目
The project was supported by the Beijing Natural Science Foundation,China (JQ18005),the National Key R&D Program of China (2016YFB0100201),the National Natural Science Foundation of China (51671003,21802003,51571072,51871078),and the China Postdoctoral Science Foundation (2018M631239).北京市自然科学基金(JQ18005),国家重点基础研究发展计划(2016YFB0100201),国家自然科学基金(51671003,21802003,51571072,51871078)和中国博士后基金(2018M631239)资助项目 （JQ18005）
