Enhanced photocatalytic activity under visible light by the synergistic effects of plasmonics and Ti3+-doping at the Ag/TiO2-x heterojunction

A heterojunction of plasmonic Ag particles on Ti3+-doped macro-/meso-porous TiO2 framework consisting of parallel microchannels, denoted as Ag/TiO2-x has been fabricated by a simple microwave-assisted process employing vitamin C as the reducing agent for forming TiO2, framework followed by photochemical deposition of Ag particles. Charge transport and recombination processes were detected through transient photocurrent responses. The visible-light photocatalytic hydrogen production rate and the apparent reaction rate constant of RhB photodegradation with 3%-Ag/TiO2-x catalyst are about 5.3 and 14.0 fold higher than those with the pristine macro-/meso-porous TiO2 framework, respectively. A mechanism based on the synergistic effects of Ag plasmonics and Ti3+-doping at the Ag/TiO2-x heterojunction is proposed, which consistently explains the high photocatalytic performance in hydrogen evolution and the improved photocatalytic decomposition of RhB under visible light. This study demonstrates the effective route to synthesize new heterojunction photocatalytic materials with multifunctional properties using low-cost and rapid microwave processes.