Optical and Electrical Enhancement of Hydrogen Evolution by MoS₂@MoO₃ Core–Shell Nanowires with Designed Tunable Plasmon Resonance

The design of transition-metal chalcogenides (TMCs) photocatalysts for water splitting is highly important, in which both light absorption and interfacial engineering play vital roles in photoexcited electron generation, electron transport, and ultimately speeding up water splitting. To this end, plasmonic metal nanomaterials with surface plasmon resonances are promising candidates. However, it is very difficult to enhance the light absorption and manage the interfacial engineering simultaneously, thus, resulting in suboptimal photocatalytic performance. Here, a doped semiconductor plasmon is proposed to optically and electrically enhance TMCs hydrogen evolution. With the tunability of plasmon resonance in a doped MoO₃ semiconductor via hydrogen reduction, the broadband absorption and good interfacial engineering are simultaneously demonstrated in flexible MoS₂@MoO₃ core–shell nanowire photocatalysts. Better energy-band alignment with MoS₂ can also be realized, thereby achieving improved photoinduced electron generation. More importantly, the defects at the interface between MoO₃ and MoS₂ are effectively reduced because of precise tunability of plasmon resonance, which enhances electron transport. As a proof of concept, this optimized hybrid nanostructure exhibits outstanding H₂ evolution characteristics (841.4 μmol h⁻¹ g⁻¹), excellent stability, and good flexibility. The value is also one of the highest hydrogen evolution activity rates to date among the two dimensional-layered visible-light photocatalysts.