Cobalt-DopedPorousCarbon Protection Layer for BismuthVanadate Photoanodes with Enhanced Stability in PhotoelectrochemicalWater 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.