超低铂合金与纳米碳结构直接集成的高效氧还原催化剂的设计

开发高效的铂(Pt)基电催化剂对于燃料电池的发展具有极其重要的意义。华中科技大学夏宝玉教授课题组报道了一种氮掺杂纳米碳结构包覆的超低Pt合金集成电催化剂并用于燃料电池氧还原反应。该Pt基催化剂复合材料在0.9 V vs. RHE的电位下展现出3.46 A mg_Pt⁻¹的质量活性, 并且在10000圈循环后几乎没有衰减。单电池测试结果表明, 其Pt利用率高达10.22 W mg_Pt⁻¹阴极, 并具有30000圈循环的优异耐久性。实验和理论研究表明, 将Co/Ni掺入Pt晶格可产生具有最佳Pt−O结合能的高应变Pt结构, 这可显著加快反应动力学。氮掺杂纳米碳结构和活性Pt组分产生的协同催化作用是提高催化活性的主要原因, 同时增强的金属-载体相互作用和优化的亲水性能可促进传质过程和水管理。这项工作可为燃料电池及其他领域的低Pt集成电催化剂的设计提供重要见解。

【图文摘要】

Fig. 1  (a) Schematic preparation, (b, c) SEM images, and (d, e) TEM images of PtCoNi@CNTs. Inset (c, d) are enlarged area of carbon encased low-Pt alloy.

Fig. 2 (a) XRD patterns, and XPS profiles for (b) Pt 4f (c) C 1s, (d) N 1s, and (e) Co 2p of various catalysts.

Fig. 3 (a) CV profiles, (b) ORR polarization curves at a sweep rate of 10 mV s⁻¹ at 1600 r min⁻¹, inset (b) is Tafel plots. (c) Mass and specific activities at a potential of 0.9 V vs. RHE. (d) Single-cell polarization curves and power density normalized by geometric MEA area and (e) MEA cathodic Pt loadings. (f) Mass activities at the voltage of 0.7 V and power densities normalized by the cathodic and total Pt loadings for both cells.

Fig. 4  Durability analysis at half-cell (a−c) and single-cell (d−f). (a) CVs and (b) LSV polarization curves before and after 10,000 potential cycles in a potential range of 0.6−1.0 V vs. RHE for PtCoNi@NCNTs and Pt/C catalysts. (c) Corresponding mass activity before and after the durability cycles. (d) Single-cell stability polarization curves before and after 30,000 cycles for PtCoNi@NCNTs and (e) Pt/C, (f) BOL and EOL cathodic mass activities at a voltage of 0.7 V for PtCoNi@NCNTs and Pt/C based single-cell before and after 30,000 ADT cycles at a voltage range of 0.65−0.95 V.

Fig. 5 (a) Pt-L₃ edge XANES spectra, (b) Fourier transform EXAFS spectra in r space, and (c) wavelet transform EXAFS of reference Pt (top), PtCo@NCNTs (middle) and PtCoNi@NCNTs (bottom). (d) DFT determined adsorption energies of atomic O and (e) projected density of states of d-orbitals for surface Pt atom in Pt(111), PtCo@NCNTs, and PtCoNi@NCNTs.

 研究详情请阅原文：

[点击下方“阅读原文”可获取全文] 

Shahid Zaman, Xinlong Tian, Yaqiong Su, Weiwei Cai, Ya Yan, Ruijuan Qi, Abdoulkader Ibro Douka, Shenghua Chen, Bo You, Hongfang Liu, Shujiang Ding, Xingpeng Guo, Bao Yu Xia. Direct integration of ultralow-platinum alloy into nanocarbon architectures for efficient oxygen reduction in fuel cells. Science Bulletin, 2021, 66(21): 2207-2216

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Science Bulletin是中国科学院主管、中国科学院和国家自然科学基金委员会共同主办、《中国科学》杂志社和Elsevier合作出版的自然科学综合性学术刊物，半月刊。报道范围主要涵盖物理学与天文学、化学、生命科学、医学科学、地球科学、材料科学、工程科学等新兴和前沿交叉学科。除Short Communication、Article、Perspective、Review等论文和评述类栏目外，还开设了News & Views、Research Highlight、Commentary、Correspondence等观点、消息类栏目。2020年影响因子11.780，位列全球73种多学科综合类期刊第7位，处于国际综合类期刊Q1区。中科院文献情报中心SCI期刊分区1区；中国科技期刊卓越行动计划领军期刊。