Enhanced Electrochemical Water Splitting Activity Using Annealed TiO2 Nanoparticles As Photoanodes

Abstract

We present the photoelectrochemical characteristics of TiO 2 nanoparticle-based photoanodes. TiO 2 nanoparticles (P25) were deposited on fluorine-doped tin oxide (FTO) substrate by spin-coating and thermally annealed in a vacuum for enhancing the active photocatalyst. At a potential of 0.4 V (versus a reversible hydrogen electrode), the annealed TiO 2 nanoparticle-based photoanode in vacuum shows a photocurrent density of 0.27 mA/cm 2 and photoconversion efficiency of (η = 0.22%), which are higher than those an of annealed TiO 2 nanoparticle-based electrode in air. The improved photoelectrochemical properties are attributed to high oxygen vacancy (OV) density with more active sides while TiO 2 nanoparticles are annealed in a vacuum (~1.33 × 10 −2 kPa) with low oxide concentration conditions. From this finding, we propose that thermal annealing can serve as an approach for fabricating the photoanodes of TiO 2 -based material consisting of a more active photocatalyst.

Enhanced photoelectrochemical water splitting by a 3D hierarchical sea urchin-like structure: ZnO nanorod arrays on TiO2 hollow hemisphere

“…In the realm of PEC water splitting, TiO 2 , with a reported maximum efficiency of approximately 0.84% STH [12], grapples with a wide band gap, though it may be an advantage of absorbing a wide spectrum of light, especially in the UV range, hinders its absorption of significant portions of the solar spectrum and rendering it inefficient under visible light [18]. Moreover, TiO 2 -based photoanodes exhibit intrinsic shortcomings, including a large band gap, low electron mobility, and short hole diffusion length, leading to limited UV light utilization and rapid carrier recombination [19]. Conversely, ZnO, with the highest reported efficiency of around 0.38% [20], encounters similar challenges with its wide band gap, impeding solar spectrum absorption.…”