Improving g-C3N4:WO3 Z-scheme photocatalytic performance under visible light by multivariate optimization of g-C3N4 synthesis

Author(s)

Cadan, Fellipe Magioli ^[1] ; Ribeiro, Caue ^[2] ; Azevedo, Eduardo Bessa ^[1]

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Chem Inst, Dept Mol Chem & Phys, Trabalhador Sao Carlense Ave 400, Sao Carlos - Brazil

^[2] Brazilian Agr Res Corp Embrapa, Natl Nanotechnol Lab Agr, 15 Novembro St 1452, Sao Carlos - Brazil

• Document type: Journal article
• Source: Applied Surface Science; v. 537, JAN 30 2021.
• Web of Science Citations: 0

Abstract

This study reports the optimization of the g-C3N4 synthesis by the melamine-annealing route using the Response Surface Methodology (RSM) and its direct coupling to WO3 by a simple sono-assisted synthesis of g-C3N4:WO3 heterojunctions, with good materials homogenization, effective interface, and proper energy levels. The optimized synthetic conditions were: 605 degrees C, 183 min, and 5 degrees C min(-1), producing a high-quality material in comparison with the ones reported in papers published between 2016 and 2020, as far as bandgap energies and specific surface areas are concerned (SSA/Eg ratio). The highest photocatalytic activity was observed in the 80:20 (wt.%) heterostructure. That material presented a high visible response, being capable of completely degrading the model-pollutant approximately four times faster than g-C3N4. The efficient flux of photo-generated electrons though a Z -Scheme heterojunction promoted a superior superoxide radical formation, resulting in increased pollutant degradation. Finally, a complete mechanism for the heterostructure photocatalysis was proposed based on theoretical and experimental results. (AU)

• FAPESP's process: 14/02739-6 - Water reuse in irrigation and aquaculture: inactivation of pharmaceuticals and endocrine disruptors by solar photo-fenton
• Grantee: Eduardo Bessa Azevedo
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/14330-8 - Studies in the synthesis and application of semiconducting nanocrystal heterostructures in artificial photosynthetic processes
• Grantee: Cauê Ribeiro de Oliveira
• Support Opportunities: Research Program on Global Climate Change - Regular Grants
• 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