Photolytic Nanostructures for Hydrogen Production

Abstract

The present work demonstrates hydrogen generation by nanowire-nanoparticle conjugate structures under visible radiation. The mechanism of hydrogen generation is attributed to photolytic cleavage of water. The nanostructures are synthesized by sol-gel and reduction chemistries and characterized by XRD, SEM, TEM, and optical spectroscopy. Photolysis is analyzed by gas chromatography. We discuss the possible mechanisms involved in the observed photolysis in terms of unique attributes of the multifunctional nanostructures, such as efficient channeling of photocarriers to redox reactions at the interfaces and self-alignment of energy levels leading to efficient charge transfer. We demonstrate conversion and quantum efficiencies of 10.6% and 22.5%, respectively, for the first hour of photolysis, under 470 nm excitation.