Bismuth oxyhalide films as photoelectrodes

AACVD BiOX films show halide-tuned bandgaps; untreated BiOBr gives about 0.38 mA cm−2 photoanodic current without a sacrificial donor.

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How were the BiOX films grown?

AACVD in air at 300 °C for 60 minutes from BiX3 in DMF.

What morphologies does SEM show?

Nanoplatelets for BiOCl and BiOI; nanoflowers for BiOBr.

Why do optical gaps narrow from Cl to I?

Halide p orbitals that form the upper valence band change in energy.

Which untreated films fail as PEC electrodes?

BiOCl (p-type) and BiOI (n-type) show poor stability.

What photocurrent does BiOBr give?

About 0.38 mA cm−2 at 1 V vs Ag/AgCl without a sacrificial donor.

Under what illumination/electrolyte was PEC run?

100 mW cm−2 in 0.5 M Na2SO4.

What CBE is quoted for 3.2 eV BiOCl?

–0.77 V vs RHE, suggesting a possible photocathode.

How does Mott–Schottky classify BiOI?

n-type, from the negative slope of the M–S plot.

What optical range was scanned?

300–1100 nm (4.1 to 1.1 eV).

Is this the highest BiOBr photocurrent without a sacrificial donor?

The authors present it as the highest recorded for BiOBr electrodes without a sacrificial electron donor.

What crystal structure type are the films?

Phase-pure tetragonal matlockite BiOX.