title: Synergetic Effect of Ti3+and Oxygen Doping on Enhancing Photoelectrochemical and Photocatalytic Properties of TiO2/g-C3N4Heterojunctions.
abstract: To improve the utilization of visible light and reduce photogenerated electron/hole recombination, Ti3+self-doped TiO2/oxygen-doped graphitic carbon nitride (Ti3+-TiO2/O-g-C3N4) heterojunctions were prepared via hydrothermal treatment of a mixture of g-C3N4and titanium oxohydride sol obtained from the reaction of TiH2with H2O2. In this way, exfoliated O-g-C3N4and Ti3+-TiO2nanoparticles were obtained. Simultaneously, strong bonding was formed between Ti3+-TiO2nanoparticles and exfoliated O-g-C3N4during the hydrothermal process. Charge transfer and recombination processes were characterized by transient photocurrent responses, electrochemical impedance test, and photoluminescence spectroscopy. The photocatalytic performances were investigated through rhodamine B degradation test under an irradiation source based on 30 W cold visible-light-emitting diode. The highest visible-light photoelectrochemical and photocatalytic activities were observed from the heterojunction with 1:2 mass ratio of Ti3+-TiO2to O-g-C3N4. The photodegradation reaction rate constant based on this heterojuction is 0.0356 min-1, which is 3.87 and 4.56 times higher than those of pristine Ti3+-TiO2and pure g-C3N4, respectively. The remarkably high photoelectrochemical and photocatalytic performances of the heterojunctions are mainly attributed to the synergetic effect of efficient photogenerated electron-hole separation, decreased electron transfer resistance from interfacial chemical hydroxy residue bonds, and oxidizing groups originating from Ti3+-TiO2and O-g-C3N4.
authors.affiliation: College of Chemistry and Materials Science, Ludong University , Yantai 264025, People's Republic of China.
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.affiliation: College of Chemistry and Materials Science, Ludong University , Yantai 264025, People's Republic of China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Xiaoqiao
authors.initials: X
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Crystal Materials, Shandong University , Jinan 250100, People's Republic of China.
authors.forename: Baibiao
authors.initials: B
authors.lastname: Huang
authors.affiliation: College of Chemistry and Materials Science, Ludong University , Yantai 264025, People's Republic of China.
authors.forename: Shanmin
authors.initials: S
authors.lastname: Gao
authors.affiliation: Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Jun
authors.identifier: http://orcid.org/0000-0003-0858-8577
authors.initials: J
authors.lastname: Lu
keywords: PEC; Ti3+ self-doped TiO2; cold LED light; heterojunctions; oxygen-doped g-C3N4; photocatalysis