SnNb2O6/NiCo-LDH Z-scheme heterojunction with regulated oxygen vacancies obtained by engineering the crystallinity for efficient and renewable photocatalytic H2 evolution

Abstract

Designing highly active and durable amorphous photocatalysts for hydrogen evolution via water splitting is still a significant challenge. Weakening of the crystallinity by engineering has been used to prepare four SnNb₂O₆/NiCo-LDH composites with different crystallinities. Among them, the amorphous–amorphous SnNb₂O₆/NiCo-LDH (SNO–LDH) Z-scheme heterojunction exhibits abundant oxygen vacancies (O_v). The as-prepared SNO–LDH (10 : 1) catalyst shows an optimal visible-light catalytic H₂ production rate of 82.2 μmol h⁻¹ g⁻¹ that is four times greater than that of pure SnNb₂O₆, and reveals a high renewability (retained rate of 75.1%) after five cyclic experiments, which is attributed to the high efficiency of the photogenerated carrier separation, and the self-recovery of active metal and oxygen vacancies by regulating the crystallinity of the recycled catalysts. This study offers a novel viewpoint into the design of highly active and durable amorphous photocatalysts for use in energy and environmental applications.