Photoelectrochemical Water Oxidation and CO2 Reduction for Artificial Photosynthesis

A light harvesting semiconductor electrode is a key component in photoelectrochemical (PEC) fuel generation and carbon dioxide conversion. There are several n-type and p-type semiconductors available but most of them suffer from low photoconversion efficiency, short service lifetime, and limited operation condition. There are several ways to improve the PEC performance, among which the surface modification of photoelectrode should be the simplest and most viable strategy. This study presents a few experimental results that the PEC performances of photoanodes and photocathodes are significantly improved by surface modifications including doping of elements (e.g., Li-doped TiO₂ nanotube arrays, metal-doped hematite and BiVO₄) and loading of catalysts (e.g., metal-deposited p-Si nanowires arrays).