Enhanced Photoelectrocatalytic Performance of TiO₂ Nanorods in Photoelectrochemical Water Splitting Cell by Using an Alcoholic Sacrificial Agent

Abstract

Photoelectrocatalytic water splitting by using various TiO2 nanostructures is a promising approach to generate hydrogen without harmful byproducts. However, their effective performance is restricted by some drawbacks such as high rapid electron-hole pair recombination and backward reaction producing H2O. Thus in this study, the probability of enhancing hydrogen generation rate by adding methanol as a sacrificial agent to the anodic chamber of a two-compartment photoelectrochemical cell is investigated. Herein, one-dimensional elongated TiO2 nanorods that were fabricated via a facile one-pot hydrothermal method are utilized as potent photoanode. Voltammetric characterizations confirm that addition of alcoholic sacrificial agent has a significant effect on photoelectrochemical properties of TiO2 nanorods which by adding 10 wt% of methanol, the photocurrent density and photoconversion efficiency increased from 0.8mA.cm-2 to 1.5mA.cm-2 and from 0.28% to 0.45%, respectively. The results of photoelectrocatalytic water splitting indicated that the hydrogen generation rate in the presence of methanol was about 1.2 times higher than that from pure water splitting. These enhancements can be attributed to the key role of methanol. Methanol molecules not only inhibit the electron-hole pair recombination but also accelerate the hydrogen generation rate by sharing their hydrogen atoms.

Photoelectrocatalytic conversion of biomethane and biogas to hydrogen over a nanostructured Ti/ TiO 2 semiconductor

“…20 Among the semiconductor materials available, TiO 2 is still widely used in photoelectrocatalytic processes, [24][25][26][27] due to advantages such as its high availability, nontoxicity, low cost, photostability, and, most importantly, adequate band gap energy levels for action as both an oxidant and a reductant. 28 Various TiO 2 nanostructures have been studied, such as nanopores, 29 nanowires, 30,31 nanorods, 32 and nanotubes. 25,27,33 Among these, arrays of TiO 2 nanotubes grown on titanium substrates by means of anodization have advantages including high surface area, which provides more active reaction sites and increases the photocatalytic activity of the material, 33 oriented electron transport, higher catalytic reaction rates, and better efficiency of light utilization.…”