# Optimized Copper-Modified Zinc Oxide Photoanodes for Solar-to-Hydrogen Evolution

## TL;DR

Researchers developed a cost-effective method to create copper-modified zinc oxide photoanodes that efficiently convert sunlight into hydrogen.

## Contribution

A single-step, scalable method for producing copper-modified zinc oxide photoanodes with high solar-to-hydrogen efficiency.

## Key findings

- The Cu-modified ZnO sample achieved a stable photocurrent of 1.22 mA cm–2 at 1.23 V RHE.
- Surface plasmon resonance from copper nanoparticles enhanced performance, confirmed by photoluminescence spectroscopy.
- Amorphous TiO2 coatings improved stability in alkaline solutions and conducted photogenerated holes effectively.

## Abstract

This work presents
a single-step method for producing cost-efficient
copper-modified zinc oxide photoanodes through scalable chemical vapor
deposition. The role of Cu incorporation is thoroughly investigated,
with the identification of an optimized loading of the metal in these
films. The optimally Cu-modified ZnO sample (CZO-5.6) achieved a stable
photocurrent of approximately 1.22 mA cm–2 at 1.23 V
RHE, along with a Faradaic efficiency of 89%.
This enhanced performance was attributed to surface plasmon resonance
(SPR) effects induced by copper nanoparticles, as evidenced by photoluminescence
spectroscopy results. To promote stability under the experimental
conditions of the PEC cell, the best-performing photoanode was further
protected using amorphous TiO2 deposited by atomic layer
deposition. Amorphous TiO2 coatings have been found to
be exceptionally stable in alkaline solutions and highly conductive
for photogenerated holes, offering a promising solution for PEC electrode
protection. This work not only describes a method for fabricating
photoanodes with high photocatalytic activity but also suggests a
low-cost route toward the development of photocatalysts for hydrogen
production.