The role of TiO2:SnO2 heterojunction for partial oxidation of methane by photoelectrocatalytic process at room temperature

Author(s)

Marques e Silva, Ricardo ; Souza, Fernanda de Lourdes ; Dias, Eduardo ; da Silva, Gelson Tiago dos Santos Tavares ; Duran, Florymar Escalona ; Rego, Arjun ; Higgins, Drew ; Ribeiro, Caue

• Document type: Journal article
• Source: Journal of Alloys and Compounds; v. 968, p. 7-pg., 2023-09-19.

Abstract

Partial Oxidation of Methane into hydrocarbons using photoelectrochemical routes is attractive from a sustainability point of view owing to the possibility of using renewable energy (i.e., solar illumination) to activate this stable molecule. However, the process demands the development of novel catalysts that can promote methane activation and oxidation in a controlled manner to increase energy conversion efficiency. Herein, we demonstrated that semiconductor heterostructures improved charge separation compared to the individual materials alone. A more effortless transfer between bands favors the separation of the electron-hole (e -/h+) pairs generated by the photoelectrocatalytic system and prevents them from recombining. This process produces reactive oxygens, essential to driving methane oxidation conversion of the C-H bond cleavage. TiO2:SnO2 semiconductor heterojunction catalysts in film shape were investigated for methane oxidation via a photo-electrocatalytic process. The methane oxidation reactions were carried out in an inflow and sealed electro-chemical system for 1 h. Liquid-state nuclear magnetic resonance revealed methanol and acetic acid as the main liquid products, where the TiO2:SnO2 heterojunction exhibited better performance with values of 30 and 8 mu mol. cm-2.h-1, respectively. Compared to their materials alone, the superior performance of the TiO2:SnO2 hetero-junction is attributed to the formation of heterostructure type II that enables a more effortless transfer between bands, facilitating the separation of the generated e -/h+ pairs under UV-Vis irradiation. The outcomes achieved here will motivate further studies for developing semiconductor heterojunction structure catalysts in photo-electrocatalysis to partially oxidize methane into valuable chemicals. (AU)

• FAPESP's process: 21/13065-0 - Development of heterostructured semiconducting nanoparticles for methane conversion by photoelectrocatalytic process
• Grantee: Ricardo Marques e Silva
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 22/10255-5 - Architectures based on metal phosphides and nitrides for photo(electro)chemical conversion of CO2 into C2+ compounds
• Grantee: Gelson Tiago dos Santos Tavares da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/21496-0 - Photoelectrochemical system design for CO2 and CH4 conversion to valuable products
• Grantee: Jéssica Ariane de Oliveira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/05149-1 - Tuning the CH4 reforming toward to green hydrogen driven by piezo-enhanced photoelectrochemical reaction
• Grantee: Jéssica Ariane de Oliveira
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 18/01258-5 - Novel chemical catalytic and photocatalytic processes for the direct conversion of methane and CO2 to products
• Grantee: José Maria Correa Bueno
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 20/09628-6 - Development of heterostructured semiconducting nanoparticles for methane conversion by photocatalytic process
• Grantee: Ricardo Marques e Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 19/10689-2 - Preparation of reaction systems for photocatalytic methane-to-methanol selective oxidation
• Grantee: Eduardo Henrique Dias
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)