Bi2O3@MoS2 heterojunction for enhanced photoelectrocatalytic hydrogen evolution

A Z-type Bi2O3@MoS2 heterojunction was successfully synthesized using a hydrothermal method. Bi2O3 microflowers served as a growth support for MoS2. The Bi2O3@MoS2-10 heterojunction demonstrated optimal photoelectrocatalytic performance as a result of adjusting the loading of MoS2. It exhibited excellent electrocatalytic hydrogen evolution performance, with an overpotential of only 223 mV vs. RHE. This value is approximately half that of pure MoS2 and one-third of Bi2O3. Under illumination, the overpotential for the hydrogen evolution reaction of the Bi2O3@MoS2-10 heterojunction decreased by ∼ 35 mV when the current density reached −10 mA cm−2, compared to dark conditions. The improved performance can be attributed to the growth of MoS2 on the Bi2O3 support, which prevents the aggregation of MoS2 nanosheets and results in a layered structure with a large surface area. Furthermore, the introduction of Bi2O3 as a co-catalyst lowers the bandgap energy of the heterojunction, facilitating efficient separation and rapid transfer of photogenerated electrons and holes. As a result, this growth induces band bending near the heterojunction interface, leading to the rearrangement of energy levels and the redistribution of charges through the interaction between Bi2O3 and MoS2. Moreover, photogenerated electrons can efficiently transfer to the heterojunction surface, participating in the reduction of H+/H3O+ ions to produce H2. This enhances the photoelectrocatalytic hydrogen evolution performance of the Bi2O3@MoS2-10 heterojunction.