Construction of 2D-composite HCa₂Nb₃O₁₀/CaNb₂O₆ heterostructured photocatalysts with enhanced hydrogen production performance

Semiconductor 2D-composite heterostructures are of great interest in water splitting due to their unique structure. In this work, we design and synthesize 2D-composite HCa₂Nb₃O₁₀/CaNb₂O₆ (HCNO/CNO) heterostructured nanosheets for the first time through sintering with a subsequent ion-exchange procedure. The achievement of such a 2D-composite nanostructure is attributed to the similar crystalline structure and intercalation-exfoliation of the layered bulk by employing tetra-n-butylammonium hydroxide (TBA⁺OH^-). Furthermore, the 2D-composite structure contributes to increasing the interfacial contact area and lattice mismatch occurring in the heterostructure. Benefiting from the construction of a heterostructure and the unique structure characteristics, the as-prepared 2D-composite HCNO/CNO nanosheets exhibit rapid photoinduced charge carrier separation and transfer, leading to significantly enhanced photo-electrochemical current response as well as photocatalytic hydrogen evolution.