Fabrication of NH2-MIL-125(Ti) incorporated TiO2 nanotube arrays composite anodes for highly efficient PEC water splitting

Abstract

Rational designing novel kind of electrodes with excellent water splitting efficiency under visible light irradiation is one of the essential targets in facing the growing energy crisis. In this paper, a hybrid electrode of TNTAs@Ti-MOF composed by nanoscaled NH2-MIL-125(Ti) decorated TiO2 nanotube arrays (TNTAs) were fabricated through a simple hydrothermal process, which was then applied as an anode in the photoelectrocatalytic (PEC) water splitting. Field emission-scanning electron microscope (FE-SEM) results show that NH2-MIL-125(Ti) nanoparticles in size of about 300 nm are mainly incorporated into the pore channels of TNTAs. The highest hydrogen production rate by using TNTAs@Ti-MOF hybrid membranes as the photoanode and platinum as the counter electrode was 132.86 μmol h−1 cm−2, which data was nearly 14 times as that of the pristine TNTAs as an anode (9.44 μmol h−1 cm−2). The improved PEC mechanism suggests that the heterogeneous structure is accompanied by the excellent light utilization, promoted charge separation, as well as the long-term photo stability are all responsible for the enhanced PEC activities. To the best of our knowledge, it is the first time report on the PEC water splitting by Ti-MOF functionalized TNTAs, and this work highlights the extended potential applications of Ti-metal substrates modified by Ti-MOF nanoparticles in PEC water splitting owing to distinct synergistic effects.