Configuration-dependent hollow heterostructures for highly efficient photocatalytic hydrogen evolution

Photocatalytic water splitting systems based on semiconductor heterojunctions show great potential for producing hydrogen fuel from renewable resources. Extensive research has been conducted to improve heterojunctions through methods such as element doping, defect regulation, surface modification, and interface engineering. However, studies on the effects of configuration in heterostructures on photocatalytic performance are still insufficient. Herein, configuration-dependent photocatalytic performances are investigated for graphitic carbon nitride (g-C₃N₄)/anatase titanium dioxide (A-TiO₂) hollow core-shell heterostructures. Two types of hollow core-shell heterostructures are ingeniously synthesized with different configurations namely g-C₃N₄/A-TiO₂ and A-TiO₂/g-C₃N₄, where g-C₃N₄/A-TiO₂ denotes a hollow core-shell heterostructure with g-C₃N₄ shell and A-TiO₂ core. Experimental and theoretical calculations show that g-C₃N₄/A-TiO₂ heterostructures have broader light absorption spectra and stronger photocurrent responses compared to A-TiO₂/g-C₃N₄. Additionally, g-C₃N₄/A-TiO₂ features improved carrier transport efficiency and more effective electron-hole separation than A-TiO₂/g-C₃N₄, highlighting the influence of heterostructural configuration on photocatalytic performance. Therefore, the photocatalytic hydrogen production performance of g-C₃N₄/A-TiO₂ is 1.4 times higher than that of A-TiO₂/g-C₃N₄. This study underscores a promising configuration-dependent strategy to design heterostructured photocatalysts for efficient photocatalysis.