Periodic density functional theory calculations are used to elucidate the mechanism of the hydrogen evolution reaction on the Mo edge of graphene-and Au(111)-supported molybdenum disulfide (MoS 2 ) electrocatalysts. Calculated potential-dependent energy barriers, employing a detailed model of the electrochemical cell, reveal that the Volmer− Heyrovskýmechanism (barrier: 1.3 eV) is favored over the Volmer−Tafel mechanism at potentials close to 0 V vs the standard hydrogen electrode (SHE). In this mechanism, H preferentially adsorbs to a S atom, but the formation of H 2 occurs with H ads on Mo. Therefore, surface diffusion of H ads is required, which contributes to the overall barrier. The Volmer−Heyrovskýbarrier is similar on both supports, which is consistent with experimental rate measurements. However, H ads diffusion is the limiting step in the overall reaction on graphene-supported MoS 2 , whereas on Au-supported MoS 2 , the Volmer and Heyrovskýbarriers both contribute. This differing behavior between supports affects how the reaction rate changes with the potential, showing the importance of considering explicit reaction barriers. Our results provide a thorough understanding of hydrogen evolution kinetics and support-tuning effects, contributing to the optimization of MoS 2 as a catalyst for this key reaction in sustainable energy production.
Hybrid nanomaterials
(HNs), the combination of organic semiconductor
ligands attached to nanocrystal semiconductor quantum dots, have applications
that span a range of practical fields, including biology, chemistry,
medical imaging, and optoelectronics. Specifically, HNs operate as
discrete, tunable systems that can perform prompt fluorescence, energy
transfer, singlet fission, upconversion, and/or thermally activated
delayed fluorescence. Interest in HNs has naturally grown over the
years due to their tunability and broad spectrum of applications.
This Review presents a brief introduction to the components of HNs,
before expanding on the characterization and applications of HNs.
Finally, the future of HN applications is discussed.
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