Cobalt-Doped Porous Carbon Protection Layer for Bismuth Vanadate Photoanodes with Enhanced Stability in Photoelectrochemical Water Splitting

Photoelectrochemical water splitting by bismuth vanadate (BiVO 4 ) photoanodes is a promising strategy for clean hydrogen production. However, poor stability caused by direct exposure to the electrolyte is one of the great obstacles to hinder its application. Herein, a cobalt-doped dopamine-derived porous carbon layer is designed as an efficient and low-cost protection for BiVO 4 photoanodes. The thick layer of around 10 nm can prevent BiVO 4 from direct exposure to the electrolyte. The electrical conductivity and porous structure of the carbon layer can guarantee the charge and mass transfer within the protection layer. As a result, the obtained BiVO 4 photoanode coated by cobalt-doped porous carbon exhibits an enhanced photocurrent density of 4.78 mA/cm 2 at 1.23 V vs reversible hydrogen electrode and stability.