Interfacial active-site-rich 0D Co3O4/1D TiO2 p-n heterojunction for enhanced photocatalytic hydrogen evolution

The hydrogen evolution activity of photocatalysts could be optimized by improving charge separation, light absorption capacity, and surface-active site number. In an attempt to engineer these critical factors in semiconductor photocatalytic processes, herein, we construct an active-site-rich 0D/1D Co3O4/TiO2 p-n hetero-junction by growing p-type Co3O4 nanoparticles onto the surface of n-type TiO2 porous fibers. The in situ-generated porous outer walls formed over the surface of TiO2 fibers can increase the accessible active sites and enhance the light capture capacity. The optimal 0D/1D Co3O4/TiO2 heterojunction exhibits the excellent H-2 evolving rate of 3.46 mmol g(-1)h(-1) and considerably higher stability than its counterparts, including TiO2 fibers, 2D/1D and 3D/1D Co3O4/TiO2 hybrids. The main reason for this eminent photocatalytic performance was due to the synergistic effect of the porous outer-walls of the TiO2 nanofibers, favourable intimate interface between Co3O4 and TiO2, built-in electric field induded by p-n heterojunction and the cocatalytic effect of Co3O4, which can create more active sites and lead to rapid charge carrier migration. This study provides an important guideline for designing surface-engineered heterostructures in photocatalytic applications.

Automated summary

The hydrogen evolution activity of photocatalysts was optimized by constructing a 0D/1D Co3O4/TiO2 heterojunction, which exhibited excellent performance due to the porous outer-walls, favorable interface contact, built-in electric field, and cocatalytic effect leading to rapid charge carrier migration. This study provides an important guideline for designing surface-engineered heterostructures in photocatalytic applications.