Natural Wollastonite-Derived Two-Dimensional Nanosheet Ni3Si2O5(OH)4 as a Novel Carrier of CdS for Efficient Photocatalytic H2 Generation

Abstract

Ni3Si2O5(OH)4 rods (NS) were synthesized via a hydrothermal method, employing natural wollastonite as a template. The hierarchical Ni3Si2O5(OH)4 rods exhibited vertically oriented nanosheets, resulting in a substantial increase in the specific surface area (from 2.24 m2/g to 178.4 m2/g). Subsequently, a CdS/Ni3Si2O5(OH)4 composite photocatalyst (CdS/NS) was prepared using a chemical deposition method. CdS was uniformly loaded onto the surface of the Ni3Si2O5(OH)4 nanosheets, successfully forming a heterojunction with Ni3Si2O5(OH)4. The CdS/NS photocatalyst in the presence of lactic acid as a sacrificial agent demonstrated an impressive H2 production rate of 4.05 mmol h−1 g−1, around 40 times higher than pure CdS. The photocorrosion of CdS was effectively solved after loading. After four cycles, the performance of CdS/NS remained stable, showing the potential for sustainable applications. After photoexcitation, electrons moved from Ni3Si2O5(OH)4 to the valence band of CdS, where they interacted with the holes via an enhanced interface contact. Simultaneously, electrons in CdS transitioned to its conduction band, facilitating hydrogenation. The enhanced performance was attributed to the improved CdS dispersion by Ni3Si2O5(OH)4 loading and efficient photogenerated carrier separation through the heterojunction formation. This work provides new perspectives for broadening the applications of mineral materials and developing heterojunction photocatalysts with good dispersibility and recyclability.