Synergistic Regulation of S-Vacancy of MoS2-Based Materials for Highly Efficient Electrocatalytic Hydrogen Evolution

Abstract

Low or excessively high concentration of S-vacancy (CS-vacancy) is disadvantageous for the hydrogen evolution reaction (HER) activity of MoS2-based materials. Additionally, alkaline water electrolysis is most likely to be utilized in the industry. Consequently, it is of great importance for fine-tuning CS-vacancy to significantly improve alkaline hydrogen evolution. Herein, we have developed a one-step Ru doping coupled to compositing with CoS2 strategy to precisely regulate CS-vacancy of MoS2-based materials for highly efficient HER. In our strategy, Ru doping favors the heterogeneous nucleation and growth of CoS2, which leads to a high crystallinity of Ru-doped CoS2 (Ru-CoS2) and rich heterogeneous interfaces between Ru-CoS2 and Ru-doped MoS2-x (Ru-MoS2-x). This facilitates the electron transfer from Ru-CoS2 to Ru-MoS2-x, thereby increasing CS-vacancy of MoS2-based materials. Additionally, the electron injection effect increases gradually with an increase in the mass of Co precursor (mCo), which implies more S2- leaching from MoS2 at higher mCo. Subsequently, CS-vacancy of the as-synthesized samples is precisely regulated by the synergistic engineering of Ru doping and compositing with CoS2. At CS-vacancy = 17.1%, a balance between the intrinsic activity and the number of exposed Mo atoms (EMAs) to boost highly active EMAs should be realized. Therefore, the typical samples demonstrate excellent alkaline HER activity, such as a low overpotential of 170 mV at 100 mA cm−2 and a TOF of 4.29 s−1 at -0.2 V. Our results show promise for important applications in the fields of electrocatalysis or energy conversion.

Engineering Rich Active Sites and Efficient Water Dissociation for Ni-Doped MoS2/CoS2 Hierarchical Structures toward Excellent Alkaline Hydrogen Evolution

“…Figure a displays X-ray diffraction (XRD) patterns of Ni-MoS 2 -CoS 2 -CC-0.3 and MoS 2 -CoS 2 -CC. Besides a peak at 2θ = 26.2° being from CC, these two samples almost exhibit the same diffraction peaks located at 2θ = 32.8, 36.3, 39.8, 46.3, and 55.0° that exactly match the (200), (210), (211), (220), and (311) planes of CoS 2 (JCPDS: 41-1471), respectively. Remarkably, the weak peak at 2θ = 14.4° is attributed to the (002) plane of 2H-MoS 2 (JCPDS: 37-1492) from Figure a.…”

In situ laser-assisted synthesis of MoS2 anchored on 3D porous graphene foam for enhanced alkaline hydrogen generation

“…37 Third, S defect engineering induces the exposure of Mo atoms, which act as newborn active sites for the HER process, introducing gap states that allow for favorable hydrogen binding. 39,50,51 Finally, conductive LIG endows LIG/MoS 2 with effective charge transferability.…”

“…states that allow for favorable hydrogen binding. 39,50,51 Finally, conductive LIG endows LIG/MoS 2 with effective charge transferability. To verify the above opinion, electrical C dl was studied to calculate the ECSA.…”

Emerging heterostructured C3N4photocatalysts for photocatalytic environmental pollutant elimination and sterilization

“…[2][3][4][5][6] Furthermore, the photocatalysis method has been considered as a feasible means for harvesting light energy in chemical bonds through different photoexcited reactions, like organic pollutant oxidation, CO 2 reduction, H 2 O splitting, H 2 O 2 preparation and valued organics synthesis. [7][8][9][10][11][12][13][14][15] Over recent decades, a considerable number of semiconductors such as metal oxides, metal sulfides, and nitride materials have been exploited as photocatalysts for various photocatalytic reactions. [16][17][18][19][20] Among them, graphitic carbon nitride (g-C 3 N 4 ) possessing outstanding light-response ability has shown great promise because of its facile synthesis, tunable band gap structure, good chemical stability, and environmentally friendly properties.…”