abstract
Polymeric carbon nitride-hydrogen peroxide adduct (PCN-H2O2) has been prepared, thoroughly characterised and its application for selective photocatalytic conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxaldehyde (FDC) in aqueous suspension has been studied. The PCN-H2O2 adduct is stable in aqueous suspension under UV and solar irradiation up to 100 degrees C. It is also stable up to 200 degrees C if heated in air, while at temperatures close to 300 degrees C its decomposition takes place. Based on the obtained characterisation data it has been proposed that H2O2 attaches to the non-polymerised carbon nitride species and to the heptazine nitrogen atoms, thus producing strong hydrogen bonding within the PCN-H2O2 adduct. The blockage of the surface amino-groups in PCN-H2O2 by H2O2 hinders the interaction of HMF with these sites, which are responsible for unselective substrate conversion. PCN-H2O2, although being less active, possesses a superior selectivity in natural solar light assisted oxidation of HMF to FDC reaching 80% with respect to its thermally etched PCN counterpart, which gives rise to a 40-50% selectivity. We believe that the exceptional performance of the applied photocatalyst in the selective photocatalytic conversion of HMF to a high added value FDC in a green solvent under natural illumination makes a significant contribution to the development of environmentally friendly technologies for biomass valorisation. (C) 2018 Elsevier Inc. All rights reserved.
keywords
METAL-FREE OXIDATION; VISIBLE-LIGHT; AEROBIC OXIDATION; ORGANIC TRANSFORMATIONS; WATER; TIO2; CATALYSTS; BIOMASS; 2,5-DIFORMYLFURAN; PERFORMANCE
subject category
Chemistry; Engineering
authors
Ilkaeva, M; Krivtsov, I; Garcia-Lopez, EI; Marci, G; Khainakova, O; Garcia, JR; Palmisano, L; Diaz, E; Ordonez, S
our authors
Marina Ilkaeva
Junior Researcheracknowledgements
We gratefully acknowledge financial support from the Spanish MINECO (MAT2013-40950-R, MAT2016-78155-C2-1-R, CTQ2014-52956-C3-1-R, and Severo Ochoa PhD grant BP-14-029 to M.I.) and FEDER. IK acknowledges financial support from Ministry of Education and Science of the Russian Federation (grant No. 4.9722.2017/8.9) and grateful for the support by Act 211 Government of the Russian Federation, contract No. 02.A03.21.0011.