Zhang Hao, Wang Zhiqiang, Ma Chenglong, Zhou Zhenhua, Cao Limei, Gong Xueqing, Dong Chunxiao, Yang Ji
State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Processes, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China.
Key Laboratory for Advanced Materials, Center for Computational Chemistry and Research Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, P. R. China.
ChemSusChem. 2021 Mar 5;14(5):1388-1395. doi: 10.1002/cssc.202002960. Epub 2021 Feb 2.
Identifying high-performance non-precious metal-based catalysts at the cathode is a major challenge for future practical applications. Herein, a soft-template route through a self-assembly arrangement of sulfur sources was successfully developed, facilitating the anion exchange. In addition, compared with pristine cobalt disulfide synthesized without templates, the cobalt disulfide prepared using the new method presented a lattice shrinking phenomenon due to the hindrance of cobalt hydroxide crystal cell. Based on X-ray absorption spectroscopy (XAS) and density functional theory (DFT) calculation, increased occupancy of e orbitals was verified for the cobalt disulfide after shrinkage, which was the main factor for enhancing the intrinsic activity of the catalyst. Besides the microscopic morphologic structure, elementary composition, and the valence state of the elements, the possible growth process of the cobalt disulfide was also discussed in detail. As catalyst for the oxygen reduction reaction, CoS showed a similar half-wave potential (0.81 vs. 0.84 V for Pt/C) and higher diffusion-limiting current density (reaching 5.33 vs. 5.19 mA cm for Pt/C) than a commercial Pt/C catalyst. Hence, our results provide a rational design direction for this type of catalysts.
识别高性能的阴极非贵金属基催化剂是未来实际应用中的一项重大挑战。在此，通过硫源的自组装排列成功开发了一种软模板路线，促进了阴离子交换。此外，与无模板合成的原始二硫化钴相比，采用新方法制备的二硫化钴由于氢氧化钴晶胞的阻碍而呈现出晶格收缩现象。基于X射线吸收光谱（XAS）和密度泛函理论（DFT）计算，验证了收缩后二硫化钴的e轨道占有率增加，这是提高催化剂本征活性的主要因素。除了微观形态结构、元素组成和元素的价态外，还详细讨论了二硫化钴可能的生长过程。作为氧还原反应的催化剂，CoS表现出与商业Pt/C催化剂相似的半波电位（0.81 V对Pt/C的0.84 V）和更高的扩散极限电流密度（达到5.33 mA cm对Pt/C的5.19 mA cm）。因此，我们的结果为这类催化剂提供了合理的设计方向。
