Inexpensive and efficient catalysts are crucial to industrial adoption of the electrochemical hydrogen evolution reaction (HER) to produce hydrogen. Although two‐dimensional (2D) MoS2 materials have large specific surface areas, the catalytic efficiency is normally low. In this work, Ag and other dopants are plasma‐implanted into MoS2 to tailor the surface and interface to enhance the HER activity. The HER activty increases initially and then decreases with increasing dopant concentrations and implantation of Ag is observed to produce better results than Ti, Zr, Cr, N, and C. At a current density of 400 mA cm−2, the overpotential of Ag500‐MoS2@Ni3S2/NF is 150 mV and the Tafel slope is 41.7 mV dec−1. First‐principles calculation and experimental results reveal that Ag has higher hydrogen adsorption activity than the other dopants and the recovered S sites on the basal plane caused by plasma doping facilitate water splitting. In the two‐electrode overall water splitting system with Ag500‐MoS2@Ni3S2/NF, a small cell voltage of 1.47 V yields 10 mA cm−2 and very little degradation is observed after operation for 70 hours. The results reveal a flexible and controllable strategy to optimize the surface and interface of MoS2 boding well for hydrogen production by commercial water splitting.
Flexible rechargeable Zn//Ni batteries are attractive owing to their high energy density, good safety, inexpensive cost, and simple manufacturing process. However, the effects of metal doping on the properties of Ni 3 S 2 cathodes in Zn/Ni batteries are not well understood. Herein, a binder-free Ni 3 S 2 electrode is doped with Zn and Co and the nanocomposite structures are prepared on nickel foam (named ZCNS/NF) by a simple two-step hydrothermal technique. The ZCNS/NF//Zn battery delivers excellent electrochemical performance such as a working voltage window can be as high as 2.05 V, a capacity of 2.3 mAh cm −2 at 12 mA cm −2 , and 82% retention going through 2000 cycles at 20 mA cm −2 . The battery has a maximum output area energy density of 1.8 mWh cm −2 (462 Wh kg −1 ) and a power density of 36.8 mW cm −2 (9.2 kW kg −1 ). In addition, the flexible battery remains operational while being bent at a large angle and even punctured. The high performance and robustness of the composite cathode suggest that the design principle and materials have large commercial potential in Ni//Zn batteries.
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