The demand of clean energy calls for efficient and low‐cost hydrogen evolution reaction electrocatalysts. Fabricating hybrid catalysts from noble/non‐noble catalysts is a practical route to reducing the consumption of noble metals and enhancing catalytic efficiency. Here, 2H‐MoS2 is etched and edge‐doped with Pt nanoparticles using focused ion beam and photoreduction techniques. Precise comparison of as‐prepared samples demonstrates that the enhancement of catalytic performance can be controlled through tuning the catalyst defect length. On this basis, remarkably high performance is obtained by designing a specific defect array that is superior to commercial Pt/C with less Pt loading and higher mass activity. It has been proved by experimentation and COMSOL Multiphysics simulations that the promotion of catalytic activity not only benefits from the synergistic effect of Pt and edge active sites, but also contributes to the increased potential at the edges of the designed defect. This study sheds light on the mechanism of understanding nanoscale edge‐doped hybrid catalysts and provides a feasible strategy for the full utilization of noble metals.
Microsupercapacitors (MSCs) are of increasing interest for powering microelectronic systems, while their applications are still limited by insufficient energy densities due to relatively large sizes. To address this critical challenge,...
Molybdenum disulfide (MoS 2 ), a typical transition metal dichalcogenide, has drawn massive attention in the field of electrocatalytic hydrogen (H 2 ) production. Defect engineering is one of the most feasible ways to enhance the hydrogen evolution reaction (HER) activity of MoS 2 , while there still remains a great challenge to achieve precise adaptation of defect structures to desirable electronic structures and surface properties. Herein, MoS 2 electrocatalysts with stepped edge defect structures are manufactured by focused ion beam etching for superior HER performance. Comparing with defects with ordinary vertical edges, the stepped samples demonstrate much lower overpotential (−115 mV at the current density of −10 mA•cm −2 ), tremendously accelerated kinetics (Tafel slope of 36.0 mV•dec −1 ), and relatively high stability. The great leap of HER activity mainly benefits from the direct control of both the electronic structure and surface property of the material via accurate manipulation. According to the results of density functional theory calculation, contact angle test, and COMSOL Multiphysics simulation, the stepped edges not only speed up the generation rate of H 2 by more optimized free energy of hydrogen adsorption and more suitable band structure for higher conductivity but also shorten the desorption time of H 2 on the electrode surface attributing to its unique hydrophilic structure. It is believed that this study would play a constructive role in extending the design ideas of ultrahigh-performance MoS 2 -based electrocatalysts.
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