Constructing Particulate p-n Heterojunction Mo:SrTiO3/NiO@Ni(OH)(2) for Enhanced H-2 Evolution under Simulated Solar Light

Author(s)

Centurion, Higor A. ; Rabelo, Lucas G. ; Rodriguez-Gutierrez, Ingrid ; Ferrer, Mateus M. ; Bettini, Jefferson ; Wender, Heberton ; Rossi, Liane M. ; Souza, Flavio L. ; Goncalves, Renato, V

• Document type: Journal article
• Source: ACS APPLIED ENERGY MATERIALS; v. 5, n. 10, p. 12-pg., 2022-10-12.

Abstract

The global environmental issues associated with the use of fossil fuels lead to an urgent need for renewable energy sources, especially those free of CO2 emissions, such as green hydrogen. In this work, we successfully synthesized Mo-doped SrTiO3 by a molten salt method for photocatalytic hydrogen production under simulated solar light (AM 1.5G illumination). As a strategy to enhance the photocatalytic performance of Mo:SrTiO3, nickel-based nanoparticles (NiO@Ni(OH)(2)) were deposited onto the surface of the particles by modified magnetron sputtering to form a p-n heterojunction (HJ), resulting in the photocatalytic improvement of around 30-fold concerning pristine SrTiO3. Theoretical investigation of the electronic band structure, by DFT, reveals that the addition of Mo as a dopant leads to the formation of midgap states near the conduction band, further attributed to the photoactivity of Mo:SrTiO3 under visible-light illumination (>400 nm). The obtained structure, Mo:SrTiO3/NiO@Ni(OH)(2), had its electronic behavior studied by XPS, Mott-Schottky analysis, and UV-vis spectroscopy, leading to the construction of a band diagram that confirms type-II p-n HJ formation. Remarkably, the formation of the HJ was responsible for establishing an internal electric field, which drives the photogenerated holes to the NiO@Ni(OH)(2) structure, leading to the suppression of electron-hole recombination, observed by the reduction of the PL signal. (AU)

• 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
• FAPESP's process: 20/15230-5 - Research Centre for Greenhouse Gas Innovation - RCG2I
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 18/11059-0 - Study of electronic and structural properties of SrTiO3/Fe2TiO5, SrTiO3 BiVO4 and SrTiO3/CuWO4 junctions for the formation of tandem systems for hydrogen production from water and sunlight
• Grantee: Higor Andrade Centurion
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program