Direct growth of ultrasmall bimetallic AuPd nanoparticles supported on nitrided carbon towards ethanol electrooxidation
Direct growth of ultrasmall bimetallic AuPd nanoparticles supported on nitrided carbon towards ethanol electrooxidation
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DOI：
10.1016/j.electacta.2018.03.017
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发表时间：
2018-04
影响因子：
6.6
通讯作者：
Yue Yang;Lei Jin;Ben Liu;Peter Kerns;Jie He
中科院分区：
文献类型：
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作者：
Yue Yang;Lei Jin;Ben Liu;Peter Kerns;Jie He
双金属纳米粒子（NPs）显示出有趣的协同作用，以提高在电催化醇氧化的活性和耐久性相比，单组分金属纳米粒子。通常在溶液中进行的碳纳米颗粒的合成带来了在导电碳载体上分离、负载和分散这些纳米颗粒的挑战。本文报道了在氮化碳载体上直接生长尺寸范围为2-5 nm的明确定义的AuPd纳米颗粒。我们的方法是基于种子介导的生长方法，使用Au种子（1.8 ± 0.3 nm）支持氮化碳。我们表明，的尺寸和表面组成的cNONPs是精确可控的。所得核-壳AuPd NPs是热稳定的，并且当在250 °C下热活化1小时时，它们可以转化为合金化的AuPd NPs。结合电子显微镜、X射线衍射分析、X射线光电子能谱和电化学还原催化剂的表面氧脱附研究了AuPd合金化纳米颗粒的化学组成。与单组分纳米粒子相比，AuPd合金化纳米粒子对乙醇电氧化的催化活性、稳定性、抗中毒性和抗电荷转移性都有很大提高。Au 0.45 Pd 0.55 -5 nm催化剂对乙醇氧化的比活度为1.11 mA/cm 2，质量活度>0.4 A/mg金属，比市售Pd/C催化剂高5倍左右。我们预计，这种合成方法将有兴趣制备金属电催化剂，具有明确的纳米结构和组成直接在导电碳在燃料电池和电池的应用。
Bimetallic nanoparticles (NPs) show interesting synergy to enhance the activity and durability in electrocatalytic alcohol oxidation compared to single-component metal NPs. The synthesis of bimetallic NPs often carried out in solution brings challenges in separating, loading and dispersing these NPs on conductive carbon supports. We herein report the direct growth of well-defined AuPd bimetallic NPs in the size range of 2–5 nm on nitrided carbon support. Our method is based on a seed-mediated growth method using Au seeds (1.8 ± 0.3 nm) supported on nitrided carbon. We show that the sizes and surface compositions of bimetallic NPs are precisely controllable. The resultant core-shell AuPd bimetallic NPs are thermally stable and they can be converted to alloyed AuPd NPs when subjected to thermal activation at 250 °C for 1 h. The chemical compositions of the AuPd alloyed NPs have been investigated by combining electron microscopy dispersive X-ray analysis, X-ray photoelectron spectroscopy and surface oxygen desorption using electrochemical reduction of catalysts. The catalytic activity, stability, poisoning tolerance and charge transfer resistance of AuPd alloyed NPs for the ethanol electrooxidation are largely enhanced compared to single-component NPs. Au0.45Pd0.55-5 nm exhibited the superior specific activity of 1.11 mA/cm2and mass activity of >0.4 A/mgmetaltoward ethanol oxidation, approximately 5 times more active than commercial Pd/C. We expect that this synthetic method will be of interest to prepare metallic electrocatalysts having defined nanostructures and compositions directly on conductive carbon for applications in fuel cells and batteries.