In situ construction of noble-metal-free coaxial core-shell 1D/3D paraotwayite-type α-Ni(OH)2@ZnIn2S4 heterojunction for enhanced photocatalytic hydrogen evolution

Photocatalytic water splitting represents a sustainable pathway for hydrogen production, yet the development of efficient and cost-effective photocatalysts remains challenging. Herein, we report the in situ construction of a noble-metal-free coaxial core-shell 1D/3D heterojunction composed of paraotwayite-type α -Ni(OH) 2 nanowire (NIOH) and ZnIn 2 S 4 (ZIS) for significantly enhanced photocatalytic hydrogen evolution. The unique 1D/3D architecture of NIOH@ZIS synergistically combines the advantages of both components: the 1D NIOH nanowires suppress charge recombination by shortening in-plane migration distances, while the 3D ZIS nanoflowers provide abundant active sites and prevent structural aggregation. Under full-spectrum irradiation, the optimized NIOH@ZIS-3 heterojunction achieves an exceptional hydrogen production rate of 7.682 mmol·g⁻¹ ·h⁻¹ , 7.8 times higher than pristine ZIS. Mechanistic studies reveal that the pn heterojunction charge transfer pathway, driven by the built-in electric field at the NIOH/ZIS interface, facilitates efficient separation and utilization of photogenerated carriers. Furthermore, the heterojunction exhibits robust stability over four photocatalytic cycles without performance degradation. This work provides a rational design strategy for high-performance, low-cost photocatalysts through structural and interfacial engineering.