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Porous platinum–silver bimetallic alloys: surface composition and strain tunability toward enhanced electrocatalysis†
Nanoscale ( IF 5.8 ) Pub Date : 2018-10-22 00:00:00 , DOI: 10.1039/c8nr06192k
Erhuan Zhang 1, 2, 3, 4, 5 , Fenfen Ma 3, 6, 7, 8, 9 , Jia Liu 1, 2, 3, 4, 5 , Jingyao Sun 10, 11, 12, 13, 14 , Wenxing Chen 1, 2, 3, 4, 5 , Hongpan Rong 1, 2, 3, 4, 5 , Xiyue Zhu 1, 2, 3, 4, 5 , Jiajia Liu 1, 2, 3, 4, 5 , Meng Xu 1, 2, 3, 4, 5 , Zhongbin Zhuang 10, 11, 12, 13, 14 , Shilv Chen 3, 6, 7, 8, 9 , Zhenhai Wen 15, 16, 17, 18, 19 , Jiatao Zhang 1, 2, 3, 4, 5
Affiliation  

Promoting surface strains in heterogeneous catalysts and heteroatomic interactions in alloying offer an effective strategy for the development of electrocatalysts with greatly enhanced activity. In this work, we design platinum–silver nanotubes (PtAg NTs) with tunable surface compositions by a controlled galvanic replacement reaction of well-defined Ag nanowires (NWs). The optimized and porous PtAg NTs (PtAg-4 NTs), with the Pt5Ag3 surface composition and (111) facet-dominant surface features, exhibit an extraordinary oxygen reduction reaction (ORR) activity that reaches a specific activity of 1.13 mA cm−2 and a mass activity of 0.688 A mg−1Pt at 0.9 V versus a reversible hydrogen electrode (RHE), which are 4.5 times and 4.3 times those of commercial Pt/C catalysts (0.25 mA cm−2 and 0.16 A mg−1Pt). Moreover, PtAg-4 NTs/C can endure under the ORR conditions over the course of 10 000 cycles with negligible activity decay. Remarkably, density functional theory simulations reveal that the porous PtAg-4 NTs exhibit enhanced adsorption interaction with adsorbates, attributed to the catalytically active sites on high-density (111) facets and modulation of the surface strain, further boosting the ORR activity and durability.

中文翻译:

多孔铂-银双金属合金:表面组成和应变可调性,可增强电催化作用†

促进多相催化剂中的表面应变和合金化中的杂原子相互作用为开发活性大大提高的电催化剂提供了有效的策略。在这项工作中,我们通过定义明确的Ag纳米线(NWs)的受控电流置换反应,设计了具有可调表面成分的铂-银纳米管(PtAg NTs)。具有Pt 5 Ag 3表面组成和(111)小面主导表面特征的优化和多孔PtAg NTs(PtAg-4 NTs)表现出非凡的氧还原反应(ORR)活性,可达到1.13 mA cm的比活-2和0.688 A的质量活性毫克-1的Pt在0.9伏可逆氢电极(RHE),其是市售Pt / C催化剂(0.25 mA cm -2和0.16 A mg -1 Pt)的4.5倍和4.3倍。此外,PtAg-4 NTs / C可以在ORR条件下承受10,000个循环的过程中的活性衰减可忽略不计。值得注意的是,密度泛函理论模拟表明,多孔PtAg-4 NTs与被吸附物的吸附作用增强,这归因于高密度(111)小面上的催化活性位和表面应变的调节,从而进一步提高了ORR活性和耐久性。
更新日期:2018-10-22
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