Pseudobrookite Fe2TiO5 Nanoparticles Loaded with Earth-Abundant Nanosized NiO and Co3O4 Cocatalysts for Photocatalytic O-2 Evolution via Solar Water Splitting

Author(s)

Melo, Mauricio A. ; Centurion, Higor A. ; Lucas, Thalles T. A. ; Muche, Dereck N. F. ; Souza, Flavio L. ; Goncalves, Renato, V

• Document type: Journal article
• Source: ACS APPLIED NANO MATERIALS; v. 3, n. 9, p. 15-pg., 2020-09-25.

Abstract

Semiconductor-based solar water splitting is a promising strategy for the production of fuels from a clean and sustainable source, following the global trend of replacing fossil fuels. Herein, a systematic study of the application of single-phase pseudobrookite Fe2TiO5 nanoparticles as oxygen-evolving photocatalyst for water splitting, in a suspended particle system, is presented. A solvothermal route was employed for the synthesis of Fe2TiO5 nanoparticles with average diameter of (34 +/- 8) nm. The obtained orange powder absorbs a broad portion of the solar spectrum (band gap of 2.1 eV) and produces 7.0 mu mol of O-2 within 5 h, under visible light irradiation. In order to enhance the catalytic activity of Fe2TiO5, NiO and Co3O4 cocatalyst nanoparticles were, separately, attached to the surface through the conventional impregnation and the magnetron sputtering deposition (MSD) methods. The homogeneous coverage with cocatalysts nanoparticles provided by the latter, allied to the reduced dimensions of the formed oxide nanoparticles (similar to 1 nm), resulted in an enhanced photoactivity of Fe2TiO5. The Co3O4-modified materials prepared through magnetron sputtering and impregnation depositions produced 58.8 and 26.2 mu mol of O-2 within 5 h under visible light, respectively. Similar behavior was observed for the NiO-modified nanomaterial, which generated 25.5 and 12.6 mu mol of O-2, respectively. These results reflect the potentiality of Fe2TiO5 nanoparticles to be employed as a particulate water splitting photocatalyst, especially when containing homogeneously distributed nanoparticles of the Co3O4 cocatalyst on the surface. Photoelectrochemical measurements further confirmed these conclusions, as Co3O4 and NiO fine deposits substantially reduce the water oxidation overpotential of a Fe2TiO5 photoanode and enhance the intensity of the anodic photocurrent due to the improved oxidation kinetics, the reduced charge recombination rates, and the lowered charge transfer resistance at the solid/liquid interface. (AU)

• FAPESP's process: 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country
• Grantee: Ana Flávia Nogueira
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 17/18716-3 - Artificial photosynthesis: development of Tandem systems for hydrogen production from water and sunlight
• Grantee: Renato Vitalino Gonçalves
• Support Opportunities: Research Grants - Young Investigators Grants