Enhanced Photoelectrocatalytic Water Splitting at Hierarchical Gd3+:TiO2 Nanostructures through Amplifying Light Reception and Surface States Passivation. Issue 3 (1st January 2015)

• Record Type: Journal Article
• Authors: Sudhagar, P.; Devadoss, Anitha; Nakata, K.; Terashima, C.; Fujishima, A.
• Is Part Of: Journal of the Electrochemical Society. Volume 162:Issue 3(2015)
• Page Start: H108
• Page End: H114
• Publication Date: 2015-01-01
• Subjects: Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0161503jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The influence of rare earth gadolinium (Gd 3+ ) ion doping on optical and photoelectrochemical properties of TiO2 is studied. The hierarchical clump-type TiO2 nanostructure was fabricated using poly-vinyl acetate as soft-template. The optical absorbance quantity of TiO2 was strikingly promoted at bandgap energy region (380 nm) by Gd 3+ doping, as well as it extend a wide absorbance in visible wavelength region (400 – 800 nm) elucidating the sub-bandgap formation. As a result, Gd 3+ :TiO2 exhibits high photocurrent density than undoped TiO2 in photoelectrocatalytic experiments. Another plausible reason for enhancing the photocurrent density at Gd 3+ :TiO2 was analyzed through electrochemical impedance spectroscopy. The underlying mechanism of surface states controlled charge transfer at TiO2 /electrolyte interfaces affected the photoelectrocatalytic hydrogen fuel generation, and compete with Gd 3+ ion doping through bottlenecking of photoelectrons trapping at surface states. The improved charge separation (e − /h + ) at Gd 3+ :TiO2 result effective photoelectron collection and thus yield 180 % higher hydrogen gas (∼ 2.34 mL.h −1 .cm −2 ) generation compare to pristine TiO2 (1.28 mL.h −1 .cm −2 ) under UV light irradiation. The improved optical and charge transfer characteristics of hierarchical TiO2 by Gd 3+ ions can be implemented to wide range of other metal oxide based photocatalytic fuel generation.