Synthesis and electrocatalytic performance of spherical core-shell tantalum (oxy)nitride@nitrided carbon composites in the oxygen reduction reaction
Synthesis and electrocatalytic performance of spherical core-shell tantalum (oxy)nitride@nitrided carbon composites in the oxygen reduction reaction
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DOI：
10.1016/j.electacta.2016.12.145
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发表时间：
2017-02
影响因子：
6.6
通讯作者：
M. Wassner;M. Eckardt;C. Gebauer;G. Bourret;N. Hüsing;R. Behm
中科院分区：
文献类型：
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作者：
M. Wassner;M. Eckardt;C. Gebauer;G. Bourret;N. Hüsing;R. Behm
作为一个正在进行的努力，以开发新型的，高活性和稳定的无铂催化剂的氧还原反应（ORR）的一部分，我们在这里报告的合成，结构特征和电化学/电催化性能的新型核壳复合材料，由一个球形氮化碳核和钽（氧）氮化物壳。（氮化）碳核应该改善材料的导电性，（氧）氮化物壳旨在保护核免受电化学腐蚀。通过溶胶-凝胶法在葡萄糖水热碳化和随后在不同温度（700 °C-1150 °C）下在氨蒸汽中氮化制备的预成型碳球上沉积钽氧化物来合成球形核壳TaOxNy@ CmNn复合颗粒。采用电子显微镜（SEM、TEM）、X射线衍射（XRD）、X射线光电子能谱（XPS）、元素分析、热重分析（TGA）、红外光谱和N2吸附测量等技术，研究了氮化温度对复合粒子结构和相组成的影响，并与电化学/电催化行为的变化进行了关联。与纯钽（氧）氮化物相比，这些核-壳复合材料显示出显著改善的ORR活性，特别是在1000 °C下氮化时，而对H2O的4-电子途径的选择性仍然需要改善。讨论了这些材料的高活性的物理起源和不同相的贡献。
As part of an ongoing effort to develop novel, highly active and stable Pt-free catalysts for the oxygen reduction reaction (ORR), we here report the synthesis, structural characteristics and electrochemical/electrocatalytic properties of novel core-shell composite materials, consisting of a spherical nitrided carbon core and a tantalum (oxy)nitride shell. The (nitrided) carbon core is supposed to improve the electrical conductivity of the material and the (oxy)nitride shell is intended to protect the core against electrochemical corrosion. Spherical core-shell TaOxNy@CmNncomposite particles were synthesized by sol-gel deposition of tantalum oxide on preformed carbon spheres, which were prepared by hydrothermal carbonization of glucose and subsequent nitriding in ammonia vapor at different temperatures (700 °C − 1150 °C). The influence of the nitriding temperature on the structure and phase composition of the resulting composite particles was evaluated, employing a variety of techniques, including electron microscopy (SEM, TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), elemental analysis, thermogravimetric analysis (TGA), IR spectroscopy and N2sorption measurements, and correlated with changes in the electrochemical/electrocatalytic behavior. These core-shell composite materials show a significantly improved ORR activity compared to pure tantalum (oxy)nitrides, in particular upon nitriding at 1000 °C, while the selectivity for the 4-electron pathway to H2O still requires improvement. The physical origin of the high activity of these materials and contributions from different phases are discussed.