Enhancement of the photoelectrochemical performance of CuWO4 films for water splitting by hydrogen treatment

- Hydrogen-treated CuWO4 film was synthesized on FTO substrates.
- Hydroxyl groups and oxygen vacancies were confirmed for the H-treated CuWO4.
- The donor density of H-treated CuWO4 was improved one order of magnitude.
- The photocurrent density for H-treated CuWO4 tripled compared with pristine CuWO4.