A novel vertical non-van der Waals (non-vdW) heterostructure of graphene and hexagonal boron nitride (G/hBN) is realized and its application in direct four-electron oxygen reduction reaction (ORR) in alkaline medium is established.

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Achieving room-temperature valley polarization in two-dimensional (2D) atomic layers (2D materials) by substitutional doping opens new avenues of applications. Here, monolayer MoS 2 , when doped with vanadium at low (0.1 atomic %) concentrations, is shown to exhibit high spin-valley coupling, and hence a high degree of valley polarization at room-temperature. The atomic layers of MoS 2 (MS) and V-doped MoS 2 (VMS) are grown via the chemical vapor deposition-assisted method. The formation of new energy states near the valence band is confirmed from band gap calculations and also from the density functional theory-based band structure analyses. Time-reversal symmetry broken energy shift in the equivalent valleys is predicted in VMS, and the roomtemperature chirality-controlled photoluminescent (PL) excitation measurements indicate such a shift in valley exciton energies (∼35 meV). An enhanced valley polarization in VMS (∼42%) is observed in comparison to that in MS (<12%), while in MS, the chirality-controlled excitations did not show the difference in emission energies. Spin Hall effect of light-based optical rotation measurements indicate the asymmetric absorption among the two different chiralities of the incident light, hence supporting the existence of room-temperature valley polarization. This study opens possibilities of room-temperature opto-spintronics using stable 2D materials.

Shape‐engineered atomically thin transition metal dichalcogenide (TMD) crystals are highly intriguing systems with regard to both fundamental and applied science. Herein, a chemical vapor deposition‐assisted generalized synthesis strategy for the triangular‐ and dendritic‐shaped TMDs and their ternary alloys is proposed, and the TMD structures' potential for electrocatalytic hydrogen evolution reaction (HER) applications is demonstrated. The alloy formation is confirmed via micro‐Raman and photoluminescence studies and further verified using transmission electron microscopy and X‐ray photoelectron spectroscopy. The HER activities of MoS2 and MoSe2 triangles are compared with those of their dendritic structures, and an enormous improvement in terms of overpotential and current density is observed for the dendritic structures. A further enhancement of the HER activity is observed in MoS2(1−x)Se2x triangular and dendritic structures, with dendritic MoS2(1−x)Se2x providing the best activity. The demonstrated nonequilibrium growth technique opens new avenues for the synthesis of morphology‐controlled, large area, complex, and atomically thin TMD structures, which can have unprecedented properties, such as the enormous catalytic activity, tunable luminescence, etc., as presented in this article.