Wei Zhan,Nan Li,Shixiang Zuo,Zhimin Guo,Chenghong Qiang,Zhengping Li,Jiangquan Ma
The rational design and synthesis of electrocatalysts for hydrogen evolution reaction (HER) remain great challenges. Herein, cubic RuSe2 (c-RuSe2) electrocatalysts with different 1T phase ratios (ranging from 20.53% to 64.97%) and crystallinities (ranging from 1.72% to 89.10%) were developed by a fast and efficient microwave-assisted synthesis method. Remarkably, the c-RuSe2 calcined at 500 °C (RuSe2-500) with 45.46% 1T phase and 86.75% crystallinity exhibited a small overpotential of 29 mV at 10 mA cm−2 and a Tafel slope of 64 mV dec−1, close to the commercial Pt/C (31 mV, 53 mV dec−1) and better than most of the reported materials. The enhanced performance of RuSe2-500 could be attributed to the crystallinity, and the 1T phase content reached a certain equilibrium at 500 °C. Moreover, RuSe2-500 had the smallest charge transfer resistance, mainly due to its abundant active centers and excellent conductivity brought by the 1T phase, which were in favor of the HER kinetics and catalytic performance. This study explored the relationship between the ratio of the 1T phase and crystallinity in c-RuSe2, and gives a new pathway to improve the activity by synergistic regulation.
1T-phase molybdenum disulphide (MoS2) is considered to be one of the most promising candidates to substitute noble metals in the hydrogen evolution reaction (HER). Fabricating single layer 1T-phase MoS2 with abundant sulfur vacancies as well as good stability to further enhance catalytic performance remains a challenge. Herein, we develop an efficient in situ TMA cation ((CH3)4N+) intercalation method to produce 1T-phase MoS2. The obtained MoS2 nanosheets comprise about 81% 1T-phase and abundant sulfur vacancies (>12%), as verified by aberration-corrected high-angle annular dark field scanning transmission electron microscopy (AC-HAADF-STEM), X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), etc. In addition, the surface of as-prepared ST-MoS2 is negatively charged, making it very stable in aqueous solution. The as-prepared ST-MoS2 exhibits excellent electrochemical HER performance with a low over-potential and a small Tafel slope as well as superior cycling stability. Furthermore, it is an excellent co-catalyst when coupled with CdS nanowires to form a CdS/ST-MoS2 heterojunction photocatalyst for the HER under visible light irradiation. It achieves a maximum H2 production rate and apparent quantum efficiency (AQE) of approximately 1187 μmol mg−1 h−1 and 73.4%, respectively, which are significantly higher than those of reported CdS/MoS2 photocatalysts.
Yue Tian,Xiaoyan Liu,Xiaoqing Cao,Dieqing Zhang,Shuning Xiao,Xinru Li,Zaiyuan Le,Xianyang Li,Hexing Li
1T MoS 2 has recently attracted growing interests for energy storage due to the excellent conductivity, expanded layer space and extra exposed active sites. However, its application is still limited due to the complicated synthesis under harsh condition and poor structural stability. Herein, we report a novel MoS 2 /Cu nanowires (NWs) by microwave-assisted self-assembly of ultrathin 1T MoS 2 onto Cu NWs with interconnected conductive network and robust one-dimensional (1D) structure. As anode material for LIBs, 1T MoS 2 /Cu NWs exhibits high capacity and stability owning to the enhanced electron transport and lithium ions intercalation. Meanwhile, the enriched nanovoids supply extended space for buffering the volume change and boosting electrolyte penetration during cycling process. Moreover, Cu doped MoS 2 could also stabilize the 1T phase, leading to the excellent anode durability. It delivers a high reversible capacity of 570.6 mAh g −1 after 250 cycles at a current density of 0.5 A g −1 . Enhanced rate performance is also achieved with excellent capacity retention of 914.6 mAh g −1 at 0.1 A g −1 and 465.2 mAh g −1 at 2 A g −1 , respectively.
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