Bifunctional PDDA-stabilized β-Fe2O3 nanoclusters for improved photoelectrocatalytic and magnetic field enhanced photocatalytic applications

Bifunctional β-Fe2O3@PDDA nanoclusters applied for the efficient photoelectrocatalytic oxygen evolution reaction and magnetic field enhanced photocatalytic degradation of pollutants.

Enhancing CO2 Conversion to CO over Plasma-Deposited Composites Based on Mixed Co and Fe Oxides

The hydrogenation of CO2 to produce CO and H2O, known as reverse-water-gas shift reaction (RWGS) is considered to be an important CO2 valorization pathway. This work is aimed at proposing the thin-film catalysts based on iron and cobalt oxides for this purpose. A series of Fe–Co nanocomposites were prepared by the plasma-enhanced chemical vapor deposition (PECVD) from organic cobalt and iron precursors on a wire-mesh support. The catalysts were characterized by SEM/EDX, XPS, XRD, and Raman spectroscopy and studied for hydrogenation of CO2 in a tubular reactor operating in the temperature range of 250–400 °C and atmospheric pressure. The Co-based catalyst, containing crystalline CoO phase, exhibited high activity toward CH4, while the Fe-based catalyst, containing crystalline Fe2O3/Fe3O4 phases, was less active and converted CO2 mainly into CO. Regarding the Fe–Co nanocomposites (incl. Fe2O3/Fe3O4 and CoO), even a small fraction of iron dramatically inhibited the production of methane. With increasing the atomic fraction of iron in the Fe–Co systems, the efficiency of the RWGS reaction at 400 °C increased up to 95% selectivity to CO and 30% conversion of CO2, which significantly exceeded the conversion for pure iron–based films (approx. 9%). The superior performance of the Fe–Co nanocomposites compared to “pure” Co and Fe–based films was proposed to be explained by assuming changes in the electronic structure of the catalyst resulting from the formation of p–n junctions between nanoparticles of cobalt and iron oxides.

WO3-decorated ZnO nanostructures for light-activated applications

Calyx-like ZnO nanostructures decorated by WO₃ nanoparticles are investigated for NO_X degradation and self-cleaning end-uses.

Novel two-step vapor-phase synthesis of UV-Vis light active Fe2O3/WO3 nanocomposites for phenol degradation

Supported Fe₂O₃/WO₃ nanocomposites were fabricated by an original vapor phase approach, involving the chemical vapor deposition (CVD) of Fe₂O₃ on Ti sheets and the subsequent radio frequency (RF)-sputtering of WO₃. Particular attention was dedicated to the control of the W/Fe ratio, in order to tailor the composition of the resulting materials. The target systems were analyzed by the joint use of complementary techniques, that is, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDXS), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), and optical absorption spectroscopy. The results showed the uniform decoration of α-Fe₂O₃ (hematite) globular particles by tiny WO₃ aggregates, whose content could be controlled by modulations of the sole sputtering time. The photocatalytic degradation of phenol in the liquid phase was selected as a test reaction for a preliminary investigation of the system behavior in wastewater treatment applications. The system activity under both UV and Vis light illumination may open doors for further material optimization in view of real-world end-uses.

Advances in photocatalytic NOx abatement through the use of Fe2O3/TiO2 nanocomposites

Supported Fe₂O₃/TiO₂ nanocomposites were prepared for the first time by a plasma-assisted route and successfully tested in photocatalytic NO_x abatement driven by solar illumination.

Vapor Phase Processing of α-Fe₂O₃ Photoelectrodes for Water Splitting: An Insight into the Structure/Property Interplay

Harvesting radiant energy to trigger water photoelectrolysis and produce clean hydrogen is receiving increasing attention in the search of alternative energy resources. In this regard, hematite (α-Fe2O3) nanostructures with controlled nano-organization have been fabricated and investigated for use as anodes in photoelectrochemical (PEC) cells. The target systems have been grown on conductive substrates by plasma enhanced-chemical vapor deposition (PE-CVD) and subjected to eventual ex situ annealing in air to further tailor their structure and properties. A detailed multitechnique approach has enabled to elucidate the interrelations between system characteristics and the generated photocurrent. The present α-Fe2O3 systems are characterized by a high purity and hierarchical morphologies consisting of nanopyramids/organized dendrites, offering a high contact area with the electrolyte. PEC data reveal a dramatic response enhancement upon thermal treatment, related to a more efficient electron transfer. The reasons underlying such a phenomenon are elucidated and discussed by transient absorption spectroscopy (TAS) studies of photogenerated charge carrier kinetics, investigated on different time scales for the first time on PE-CVD Fe2O3 nanostructures.

Magnetic ground state of nanosized β-Fe2O3 and its remarkable electronic features

In this study, we report on structural, magnetic, and electric features of β-Fe₂O₃ identifying its magnetic ground state and its potentiality in photoelectrochemical applications.

Pt-functionalized Fe2O3 photoanodes for solar water splitting: the role of hematite nano-organization and the platinum redox state

Pt/α-Fe₂O₃ nanocomposite photoanodes for solar water splitting are synthesized and deeply investigated to unravel the role of hematite nano-organization and the platinum redox state in photoelectrochemical performances.