# Photocatalytic Activity of Thin Layers Obtained via Electrodeposition and Annealing of Nanostructured WFeZn and WFeCu Alloys

## TL;DR

This paper introduces a new method for creating efficient photocatalysts for water splitting using nanostructured alloys of tungsten, iron, and zinc or copper.

## Contribution

The study presents a novel two-step synthesis method for creating light-activated oxygen evolution catalysts with high efficiency.

## Key findings

- The conversion efficiency of the photocatalysts reached approximately 30%.
- The structure of the alloy precursors favors the formation of highly active tungstate forms.
- Electrodeposition allowed precise control of composition at low cost.

## Abstract

Improvement of the efficiency of the water-splitting
process is
one of the crucial issues to be dealt with in the coming years. In
this study, a new method for the preparation of photocatalysts is
presented. Two novel light-activated oxygen evolution catalysts were
developed, consisting of oxidized forms of tungsten, iron, and zinc
or copper. In the two-step synthesis, thin layers of nanostructured
tungsten–iron–third metal alloys are electrodeposited
from an aqueous bath initially, and then they are annealed in an oxidizing
atmosphere. The electroplating technique was used in the designed
process to combine high precision in deposition and control of composition
with relatively low economic and environmental costs. In addition,
the easier formation of highly active tungstate forms in the catalysts
may be favored by the structure of the alloy precursors. Conditions
for obtaining the layers were optimized based on recorded photocurrents.
The analysis of electrode surfaces was performed using spectroscopic
and microscopic techniques. The oxygen released during the photooxidation
of water with ternary metal oxide semiconductors was monitored using
an O2 membrane sensor (Clark electrode), and the conversion
efficiency was found to be approximately 30%.