Promoting Overall Water Splitting in MoS₂/BSe Heterostructures: Insights from Time-Domain Atomistic Dynamics

The design of a suitable photocatalyst for overall water splitting is an important field of research in recent times because it leads to the production of hydrogen fuel, which is the cleanest fuel. By employing density functional theory and nonadiabatic molecular dynamics (NAMD) simulations, we herein propose MoS2/BSe van der Waals (vdW) heterostructure as a perfect photocatalyst for the water-splitting reaction. The proposed heterostructure was found to have excellent stability at ambient temperature (300 K) and in highly moist conditions. The electronic structure calculation confirms that this heterostructure has a proper band energy alignment that promotes both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The NAMD study reveals that photogenerated electron and hole transfer occurs within 245 and 401 fs, respectively, while the electron–hole recombination occurs within 576 ps. This implies that redox-active photogenerated electrons and holes are expected to participate successfully in driving the overall photocatalytic water splitting reaction. Additionally, a free energy calculation related to HER and OER reveals that the process takes place spontaneously on the respective surfaces without any cocatalyst.