Bismuth vanadate with electrostatically anchored 3D carbon nitride nano-networks as efficient photoanodes for water oxidation

In this study, we report a photoanode consisting of a polymeric/inorganic nanojunction between novel nanostructured 3D C ₃ N ₄ nano-networks and BiVO ₄ substrate. This nanojunction is formed such that 3D C ₃ N ₄ nano-networks with a positively charged surface are efficiently anchored on the BiVO ₄ photoanode with a negatively charged surface. This electrostatic self-assembly can initiate and contribute to an intimate contact at the interfaces, leading to an enhanced photoelectrochemical activity and stability compared with that fabricated by non-electrostatic assembly. The C ₃ N ₄ nano-network/BiVO ₄ photoanode achieved a remarkable photocurrent density of 4.87 mA cm ⁻² for water oxidation at 1.23 V (vs. reversible hydrogen electrode) after depositing FeOOH/NiOOH as oxygen-evolution co-catalyst, which is among the highest photocurrent densities reported so far for BiVO ₄ -based photoanodes.