Formation of Mo–Polydopamine Hollow Spheres and Their Conversions to MoO2/C and Mo2C/C for Efficient Electrochemical Energy Storage and Catalyst

4 years ago

Formation of Mo–Polydopamine Hollow Spheres and Their Conversions to MoO2/C and Mo2C/C for Efficient Electrochemical Energy Storage and Catalyst

Feifei Zhang, Limin Wang, Lianshan Sun, Yong Cheng, Qujiang Sun, Chunli Wang, Xuxu Wang

Highly uniform hierarchical Mo–polydopamine hollow spheres are synthesized for the first time through a liquid-phase reaction under ambient temperature. A self-assembly mechanism of the hollow structure of Mo–polydopamine precursor is discussed in detail, and a determined theory is proposed in a water-in-oil system. Via different annealing process, these precursors can be converted into hierarchical hollow MoO2/C and Mo2C/C composites without any distortion in shape. Owing to the well-organized structure and nanosize particle embedding, the as-prepared hollow spheres exhibit appealing performance both as the anode material for lithium-ion batteries and as the catalyst for hydrogen evolution reaction (HER). Accordingly, MoO2/C delivers a high reversible capacity of 940 mAh g−1 at 0.1 A g−1 and 775 mAh g−1 at 1 A g−1 with good rate capability and long cycle performance. Moreover, Mo2C/C also exhibits an enhanced electrocatalytic performance with a low overpotential for HER in both acidic and alkaline conditions, as well as remarkable stability. Hierarchical Mo–polydopamine hollow spheres are prepared in the water-in-oil system. Enlarged surface area and stable structure greatly enhance electrochemical and catalytic properties when applied in lithium-ion batteries and hydrogen evolution reaction. The simple and powerful synthetic procedure opens a new route to design and construct advanced functional materials for future.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/smll.201701246