Synthesis of p-Co₃O₄/n-TiO₂ Nanoparticles for Overall Water Splitting under Visible Light Irradiation.

Qiang Zhang,Zhenyin Hai,Chenyang Xue,Aoqun Jian,Shengbo Sang,Hongyan Xu

doi:10.3390/nano6080138

Abstract

p-Co3O4/n-TiO2 nanoparticles (~400 nm) for photocatalysis were prepared via carbon assisted method and sol-gel method in this work. The paper also studied the application of visible light illuminated p-Co3O4/n-TiO2 nanocomposites cocatalyst to the overall pure water splitting into H2 and O2. In addition, the H2 evolution rate of the p-Co3O4/n-TiO2 nanocomposites is 25% higher than that of the pure Co3O4 nanoparticles. Besides, according to the results of the characterizations, the scheme of visible light photocatalytic water splitting is proposed, the Co3O4 of the nanocomposites is excited by visible light, and the photo-generated electrons and holes existing on the conduction band of Co3O4 and valence band of TiO2 have endowed the photocatalytic evolution of H2 and O2 with higher efficiency. The optimal evolution rate of H2 and O2 is 8.16 μmol/h·g and 4.0 μmol/h·g, respectively.

Highlights

The sharp increase in global energy consumption makes efficient utilization of solar energy more urgent [1]
The p-Co3O4/n-TiO2 composites have a significant impact on the efficiency of photocatalytic water splitting
The formation of the p-Co3O4/n-TiO2 conjunction is proven by the TEM and H28i8g.6heVResolution Transmission Electron Microscopy (HRTEM) investigations of Co3O4, TiO2 and Co3O4-TiO2 nanoparticles

Summary

Introduction

The sharp increase in global energy consumption makes efficient utilization of solar energy more urgent [1]. Some studies researched on changing the band gap of Co3O4; the constraints of these methods are high cost and difficult controlling processes [12,13,14,15,16,17,24]. A new p-Co3O4/n-TiO2 photococatalyst is designed for overall pure water splitting under visible light irradiation, and the Co3O4 and TiO2 nanoparticles is, to the best of our knowledge, combined in nano-scale for the first time [25,26,27]. The paper presented the study on the application of visible light illuminated p-Co3O4/n-TiO2 nanocomposites cocatalyst to the overall pure water splitting into H2 and O2, and the H2 evolution rate of the p-Co3O4/n-TiO2 nanocomposites is 25% higher than that of the pure Co3O4 nanoparticles. The scheme of visible light photocatalytic water splitting is proposed based on the results of the characterizations

Synthesis

TiO2-Co3O4

Findings

Conclusions