Enhanced photoelectrochemical water splitting performance using morphology-controlled BiVO4 with W doping.

Xin Zhao,Zhong Chen

doi:10.3762/bjnano.8.264

Abstract

Nanostructures exhibit numerous merits to improve the efficiency in solar-to-energy conversion. These include shortened carrier collection pathways, an increased volume ratio between depletion layer and bulk, enhanced light capture due to multiple light scattering in nanostructures, and a high surface area for photochemical conversion reactions. In this study, we describe the synthesis of morphology-controlled W-doped BiVO4 by simply tuning the solvent ratio in precursor solutions. Planar and porous W-doped BiVO4 thin films were prepared and compared. The porous film, which exhibits increased surface area and enhanced light absorption, has displayed enhanced charge separation and interfacial charge injection. Our quantitative analysis showed an enhancement of about 50% of the photoelectrochemical performance for the porous structure compared to the planar structure. This enhancement is attributed to improved light absorption (13% increase), charge separation (14% increase), and interfacial charge injection (20% increase).

Highlights

Solar hydrogen generation is one of the most promising approaches to create clean energy and to overcome the environmental problems associated with use of conventional fossil fuels
We report the synthesis of a morphologically controlled W-doped BiVO4 by tuning the composition of the precursor solution
Considering the poor electron conductivity of BiVO4, which leads to a poor photoelectrochemical performance, we employed tungsten as a doping element because it has a higher valence than vanadium and an ionic radius close to that of vanadium

Summary

Introduction

Solar hydrogen generation is one of the most promising approaches to create clean energy and to overcome the environmental problems associated with use of conventional fossil fuels. By changing the solvent ratio, planar and porous nanostructured W-doped BiVO4 thin films were prepared. Films prepared using water precursor solutions (Figure 1d–f) show nanoporous structures.

Results

Conclusion