Metal-organic framework derived Co3O4/TiO2 heterostructure nanoarrays for promote photoelectrochemical water splitting

In this work, we proposed a simple and new method to fabricate Metal-organic frameworks (MOFs) derived Co3O4 modified TiO2 nanorods (NRs) photoelectrode by immersion and anneal treatment. The positively charged Co-MOF (ZIF-67) was adsorbed on the negatively charged TiO2 NRs by electrostatic interaction, and then annealed in air to obtain the Co3O4/TiO2 photoelectrodes. The photoelectrochemical (PEC) performance of the Co3O4/TiO2 photoelectrodes has been significantly improved compared with the pure TiO2, the best photocurrent density of Co3O4/TiO2 photoelectrode could reach 1.04 mA/cm2 (1.23 V vs RHE) which was almost 1.65 times than that of pure TiO2. On the Co3O4/TiO2 photoelectrodes, the significant improvement in PEC performance could be attributed to the constructed p-n heterostructure, which can promote charge transfer within the system and improve the efficiency of electron/hole separation. Meanwhile, under the action of the MOFs-derived Co3O4, the number of active sites increases significantly and visibly improve the photoresponse performance.