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

Photoelectrochemical water splitting by bismuth vanadate (BiVO4) 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 BiVO4 photoanodes. The thick layer of around 10 nm can prevent BiVO4 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 BiVO4 photoanode coated by cobalt-doped porous carbon exhibits an enhanced photocurrent density of 4.78 mA/cm2 at 1.23 V vs reversible hydrogen electrode and stability.