Abstract:
Photocatalytic splitting water is a promising method to obtain hydrogen energy. While design and synthesis of efficient and economical photocatalysts is one of the important contents. Janus MoSSe and WSSe
monolayers are efficient and wide sunlight harvesting photocatalysts due to their intrinsic vertical electric fields. So how is the photocatalytic performance of lateral MoSSejWSSe heterojunctions, which possesses an intra-plane interface and intrinsic vertical electric field? In the present work, the structural
property, electronic characteristic, optical property, and photocatalytic application of MoSSejWSSe lateral
heterojunctions are systematically investigated. It is found that both zigzag and armchair configurations
are semiconductors with suitable bandgaps of 1.60 eV. Besides, they possess a type-II band alignment
where electrons tend to accumulate at the coupling interface of MoSSe side and holes at WSSe side, giving
rise to a paralleled electric field in heterojunctions, which can largely promote the separation of photogenerated carriers. More remarkably, these heterojunctions exhibit pronounced solar-spectrum absorption efficiency, proper valence, and conduction band positions by initializing the redox reactions of
H2O and high carrier mobility. Intriguingly, the zigzag MoSSejWSSe heterojunction has a better photocatalytic performance in an acidic environment, and the armchair MoSSejWSSe prefers to produce H2 and O2
in a neutral environment. These fascinating properties render the intra-plane MoSSejWSSe heterojunctions as the wide solar harvesting photocatalysts in further overall water splitting.
