An overview of the mechanism, synthesis and modification of nano zerovalent iron in water treatment is provided.

A strong driving force for charge separation and transfer in semiconductors is essential for designing effective photoelectrodes for solar energy conversion. While defect engineering and polarization alignment can enhance this process, their potential interference within a photoelectrode remains unclear. Here we show that oxygen vacancies in bismuth vanadate (BiVO₄) can create defect dipoles due to a disruption of symmetry. The modified photoelectrodes exhibit a strong correlation between charge separation and transfer capability and external electrical poling, which is not seen in unmodified samples. Applying poling at −150 Volt boosts charge separation and transfer efficiency to over 90%. A photocurrent density of 6.3 mA cm⁻² is achieved on the photoelectrode after loading with a nickel-iron oxide-based cocatalyst. Furthermore, using generated holes for methane partial oxidation can produce methanol with a Faradaic efficiency of approximately 6%. These findings provide valuable insights into the photoelectrocatalytic conversion of greenhouse gases into valuable chemical products.

This Feature Article highlights the use of mixed-metal single source precursors to directly access useful complex metal oxide materials.

Single‐source precursors are used to produce nanostructured BiVO₄ photoanodes for water oxidation in a straightforward and scalable drop‐casting synthetic process. Polyoxometallate precursors, which contain both Bi and V, are produced in a one‐step reaction from commercially available starting materials. Simple annealing of the molecular precursor produces nanocrystalline BiVO₄ films. The precursor can be designed to incorporate a third metal (Co, Ni, Cu, or Zn), enabling the direct formation of doped BiVO₄ films. In particular, the Co‐ and Zn‐doped photoanodes show promise for photoelectrochemical water oxidation, with photocurrent densities >1 mA cm⁻² at 1.23 V vs reversible hydrogen electrode (RHE). Using this simple synthetic process, a 300 cm² Co‐BiVO₄ photoanode is produced, which generates a photocurrent of up to 67 mA at 1.23 V vs RHE and demonstrates the scalability of this approach.