Biomass Lignin Integrated Polymeric Carbon Nitride for Boosted Photocatalytic Hydrogen and Oxygen Evolution Reactions

• Published in: Molecular Catalysis
• Main Author: Hayat A.; Sohail M.; Hamdy M.S.; Amin M.A.; Alharthi S.; Taha T.A.; Rahman M.M.; Palamanit A.; Khan J.; Mane S.K.B.; Nawawi W.I.
• Format: Article
• Language: English
• Published: Elsevier B.V. 2022
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85121762687&doi=10.1016%2fj.mcat.2021.112064&partnerID=40&md5=fe2e05416bd1d27bef03e87552d13241

The carbon nitride (CN) has good stability, a comprehensive band structure, and a more straightforward fabrication process that makes them a top candidate for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). So far, scientists have been involved broadly in utilizing smaller carbon-based molecules to modify the CN framework for better-quality solar to fuel energy conversion. Still, the modification of material with a natural macromolecule has been explored insufficiently. In this regard, we firstly copolymerized carbon nitride (CN) by conjugating a novel monomer 2,6-dibenzolumazine through molecular integration (CNPx). The copolymerized catalyst demonstrated noteworthy improvement in photocatalytic activities as compared to pristine CN. Following this, we further combine our superior sample (CNP5.0) with the underlying biomass-based lignin molecules forming CNP-Lx. The biomass-modified CNP-Lx obtained through this process has an increased hydrogen evolution rate (HER) and oxygen evolution rate (OER) under visible light (λ=420 nm). Findings demonstrate the catalytic performance seven times higher for CNP-Lx and three times enhanced for CNPx sample than CN catalyst. These improvements can be attributed to the ultrathin nanostructure and efficient visible light absorption of the CN, well-balanced exciton states of the organic monomer, and the synergetic effect of lignin's on its surface. Lignin-activated CNP0.5 photocatalysts produced through this method can prove cost-effective and efficient alternatives for solar overall water splitting. © 2021 Elsevier B.V.