title: Temperature-boosted photocatalytic H2production and charge transfer kinetics on TiO2under UV and visible light.
abstract: This study investigates the effect of reaction temperature (298-353 K) on photocatalytic H2production in bare and platinized TiO2(Pt/TiO2) suspensions containing various organic hole scavengers (EDTA, methanol, and formic acid) under UV (λ > 320 nm) and visible light (λ > 420 nm for ligand-to-metal charge transfer). H2production rates are enhanced ∼7.8- and ∼2.5-fold in TiO2and Pt/TiO2suspensions, respectively, with EDTA under UV by simply elevating the reaction temperature from 298 K to 323 K (ΔT = 25 °C). Such a temperature-boosted increase in H2production is always observed, regardless of the TiO2crystalline structure (anatase, rutile, and an anatase/rutile mixture), type of hole scavenger, and irradiation wavelength range. It is estimated that approximately 90% of incident photons are utilized in H2production, for which the activation energy is 25.5 kJ mol-1. Detailed photoelectrochemical analyses show the positive relationship between reaction temperature and photocurrent generation, with charge carrier mobility and interfacial charge transfer improving at higher temperatures. Other possible factors, such as H2solubility and mass transport, play a limited role.
authors.affiliation: Department of Chemistry and Biology, Korea Science Academy of KAIST, Busan 47162, Korea.
authors.forename: Gonu
authors.initials: G
authors.lastname: Kim
authors.affiliation: Taejon Christian International School, Daejeon 34035, Korea.
authors.forename: Hee Joon
authors.initials: HJ
authors.lastname: Choi
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, USA.
authors.forename: Hyoung-Il
authors.initials: HI
authors.lastname: Kim
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, USA.
authors.forename: Jaehong
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Analytical and Applied Chemistry, Institut Químic de Sarrià (IQS) - School of Engineering, Universitat Ramon Llull, Barcelona 08017, Spain.
authors.forename: Damián
authors.initials: D
authors.lastname: Monllor-Satoca
authors.affiliation: School of Energy Engineering, Kyungpook National University, Daegu 41566, Korea. hwp@knu.ac.kr and School of Architectural, Civil, Environmental, and Energy Engineering, Kyungpook National University, Daegu 41566, Korea.
authors.forename: Minju
authors.initials: M
authors.lastname: Kim
authors.affiliation: School of Energy Engineering, Kyungpook National University, Daegu 41566, Korea. hwp@knu.ac.kr and School of Architectural, Civil, Environmental, and Energy Engineering, Kyungpook National University, Daegu 41566, Korea.
authors.forename: Hyunwoong
authors.initials: H
authors.lastname: Park