Sulfur-Doped Graphene-Supported Nickel-Core Palladium-Shell Nanoparticles as Efficient Oxygen Reduction and Methanol Oxidation Electrocatalyst
Sulfur-Doped Graphene-Supported Nickel-Core Palladium-Shell Nanoparticles as Efficient Oxygen Reduction and Methanol Oxidation Electrocatalyst
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DOI：
10.1021/acsaem.8b00631
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发表时间：
2018-08-01
影响因子：
6.4
通讯作者：
Tagmatarchis, Nikos
中科院分区：
文献类型：
--
作者：
Perivoliotis, Dimitrios K.;Sato, Yuta;Tagmatarchis, Nikos
用于氧还原反应（ORR）和甲醇氧化反应（MOR）的新型无铂高效电催化剂的设计一直被认为是商业化燃料电池设备开发的核心挑战。在这篇论文中，采用了一种简单的策略来制备无表面活性剂的镍核钯壳纳米颗粒，缩写为Pd@Ni-NPs，均匀分布在硫掺杂的石墨烯（SG）上。 Pd@Ni-NPs/SG杂化材料是通过采用改进的多元醇方法原位制备Ni-NPs/SG，然后通过电取代方法沉积Pd壳，并通过拉曼和红外光谱、STEM/EELS、SEM和EDS以及XRD和TGA进行补充表征来实现的。鉴于混合物的电催化性能，优化了 Pd-Ni 摩尔比。有趣的是，Pd@Ni-NPs/SG杂化物被证明是一种高效且稳定的ORR和MOR电催化剂。它表现出与基准 Pd/C 催化剂相当的初始 ORR 性能，并且重要的是具有更高的稳定性，因为在 2,000 次电位循环后，它的扩散极限和动力学电流密度分别高出 36% 和 67%，且初始活性损失最小。对反应动力学的进一步研究表明，Pd@Ni-NPs/SG 可以四电子直接将氧还原为水，塔菲尔斜率为 -48 mV dec(-1)/-116 mV dec(-1)，该值更接近多晶铂的值。此外，Pd@Ni-NPs/SG的MOR比活性比Pd/C提高了82%（2.26 mA cm(-2) vs 1.24 mA cm(-2)），并且具有更好的抗中毒能力。总体而言，Pd@Ni-NPs/SG杂化材料是一种高效、低成本的电催化剂，在高性能能量转换装置中展现出巨大的应用潜力。
The design of novel platinum-free highly efficient electrocatalysts for the oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) has been regarded as the core challenge toward the development of commercially available fuel cell devices. In this contribution, a facile strategy was applied to prepare surfactant-free nickel-core palladium-shell nanoparticles, abbreviated as Pd@Ni-NPs, uniformly distributed on sulfur-doped graphene (SG). The Pd@Ni-NPs/SG hybrid material was realized by employing a modified polyol method for the in situ preparation of Ni-NPs/SG, followed by deposition of a Pd shell through the galvanic replacement method and complementary characterization by Raman and IR spectroscopy, STEM/EELS, SEM, and EDS as well as XRD and TGA. The Pd-to-Ni molar ratio was optimized in view of the hybrid's electrocatalytic performance. Interestingly, the Pd@Ni-NPs/SG hybrid was proved to be a highly efficient and stable electrocatalyst toward ORR and MOR. It exhibited comparable initial ORR performance with the benchmark Pd/C catalyst and importantly greater stability, as after 2,000 potential cycles it possesses 36% and 67% higher diffusion-limited and kinetic current density, respectively, having a minimal loss of its initial activity. Further investigations on the reaction kinetics showed a four-electron direct reduction of oxygen to water for the Pd@Ni-NPs/SG as well as Tafel slopes of -48 mV dec(-1)/-116 mV dec(-1), values much closer to those proposed for the polycrystalline platinum. In addition, Pd@Ni-NPs/SG revealed enhanced MOR specific activity by 82% over Pd/C (2.26 mA cm(-2) vs 1.24 mA cm(-2)) and by far better antipoisoning abilities. Overall, Pd@Ni-NPs/SG hybrid is a highly efficient and low-cost electrocatalyst, revealing huge potential for application in high-performance energy conversion devices.