An earth-abundant, low-cost cobalt porphyrin complex (CoTCPP) is designed as a molecular catalyst to work on three-dimensional BiVO₄ film electrode for water oxidation for the first time. Under illumination of a 100 mW cm^–2 Xe lamp, the CoTCPP-functionalized BiVO₄ photoanode exhibits a 2-fold enhancement in photocurrent density at 1.23 V vs RHE and nearly a 450 mV cathodic shift at 0.5 mA cm⁻² photocurrent density relative to bare BiVO₄ in 0.1 M Na₂SO₄ (pH = 6.8). Simultaneously, stoichiometric oxygen and hydrogen are generated with a faradic efficiency of 80% over 4 h. The activity and stability of the BiVO₄ photoanode are dramatically increased by molecular CoTCPP, giving rise to higher performance than previously reported noble metal ruthenium complex-modified BiVO₄ photoanode. By using hydrogen peroxide as the hole scavenger, we demonstrate that molecular CoTCPP catalyst greatly suppresses the hole–electron recombination on the surface of BiVO₄ semiconductor, which offers a promising route toward high efficiency, low cost, practical solar fuel generation device.

ACS Appl. Mater. Interfaces, Article ASAP

DOI: 10.1021/acsami.6b04510

Publication Date (Web): June 30, 2016