Interface Engineering of MoS2-Modified Graphitic Carbon Nitride Nano-photocatalysts for an Efficient Hydrogen Evolution Reaction
Journal
ChemPlusChem
Date Issued
July 2020
Abstract
Understanding of photochemical charge transfer processes at nanoscale heterojunctions is essential in developing effective catalysts. Here, we utilize a controllable synthesis method and a combination of optical absorption, photoluminescence, and electrochemical impedance spectroscopic studies to investigate the effect of MoS2 nanosheet lateral dimension and edge length size on the photochemical behavior of MoS2-modified graphitic carbon nitride (g-C3N4) heterojunctions. These nano-heterostructures, which comprise interlayer junctions with variable area (i. e., MoS2 lateral size ranges from 18 nm to 52 nm), provide a size-tunable interfacial charge transfer through the MoS2/g-C3N4 contacts, while exposing a large fraction of surface MoS2 edge sites available for the hydrogen evolution reaction. Importantly, modification of g-C3N4 with MoS2 layers of 39±5 nm lateral size (20 wt % loading) creates interfacial contacts with relatively large number of MoS2 edge sites and efficient electronic transport phenomena, yielding a high photocatalytic H2-production activity of 1497 μmol h−1 gcat−1 and an apparent QY of 3.3 % at 410 nm light irradiation. This study thus offers a design strategy to improve light energy conversion efficiency of catalysts by engineering interfaces at the nanoscale in 2D-layered heterojunction materials.