In this work, we report a typical Mott-Schottky electrocatalyst composed of metallic Co and semiconducting MoSe2 on carbon nanotubes (Co/MoSe2@CNT), prepared by sol-gel process followed by thermal reduction treatment. The characterization results and theoretical calculations reveal that Co/MoSe2 Mott-Schottky heterojunction can cause electron redistribution and establish an build-in electric field, which can not only optimize the adsorption energy of the reaction intermediates, but also promote the charge transfer during the hydrogen evolution process. Thus, Co/MoSe2@CNT deliver excellent catalytic activity with a low overpotential of 185 mV at 10 mA cm-2 and a small Tafel slope of 69 mV dec-1. This work provides a new strategy for constructing Co/MoSe2 Mott-Schottky heterojunc-tions and highlighting the Mott-Schottky effect, which may inspire the development of more efficient Mott Schottky electrocatalysts for H2 production in the future.

MoSe2 as one graphene-like 2D transition metal selenide has attracted great attention. However, its application for the hydrogen evolution reaction (HER) is still restricted by the poor electrical conductivity and structural restacking. In this work, an excellent electro-catalyst for hydrogen production is developed based on the in-situ synthesis of V-doped MoSe2 confined on carbon black nanoparticles (denoted as V-MoSe2/CB) via a sol-gel process. The characterization results show the carbon black nanoparticles can protect the V-MoSe2 nanosheets from agglomeration, resulting in ultra-thin thickness and short vertical lattice arrays. Meanwhile, Density func-tional theory (DFT) calculations indicate that vanadium doping can optimize the electronic structure of MoSe2. Accordingly, compared to pure MoSe2, V-MoSe2 and MoSe2/CB electrocatalyst, V-MoSe2/CB exhibits improved electrocatalytic activity with a small overpoten-tial of 166 mV at -10 mA cm-2 and a small Tafel slope of 65 mV dec-1. This work paves a new way for improving the HER performance through synergistic morphology, structure and electronic regulation.