Cerium oxide integration and oxygen doping of g-C₃N₄ for boosted solar removal of emerging pollutants and water disinfection
Eryk Fernandes, Paweł Mazierski, Magdalena Miodyńska, Kostiantyn Nikiforow, Tomasz Klimczuk, Adriana Zaleska‐Medynska, Rui C. Martins, João Gomes
Abstract
The high recombination of electron/hole pairs and a low specific surface area are typical limiting characteristics of graphitic carbon nitride, resulting in low photoactivities. The development of modifications to surpass such drawbacks is fundamental for the further application of this material. Herein, the addition of low concentrations of citric acid and cerium nitrate in the catalyst thermal polymerization synthesis was employed and optimized to enhance its solar photocatalytic performance. The introduction of oxygen and the formation of cerium oxide deeply affected the catalyst light absorption and structure, achieving up to 3 times higher surface areas and distinct morphologies. Incorporating cerium oxide significantly increased the material's photocatalytic activity, while adding citric acid may facilitate the metal oxide impregnation and act as a structural-directing agent. The catalyst with an optimum concentration of additives achieved 74–76 % removals of a paraben's mixture in 180 min of solar photocatalysis, with its main activation occurring in the near-visible wavelengths (390 nm). The increase in the water matrix complexity reduced the catalyst activity. Still, the modified materials significantly improved the removal of the six chemical contaminants evaluated and Escherichia coli bacteria in synthetic and secondary wastewater effluent. • CeO 2 and oxygen atoms were successfully introduced into the g-C 3 N 4 structure. • The modifications performed led to an increased surface area and extended absorption spectrum. • Best modified catalyst, Ce22, led to 74–76 % paraben's removal in 180 min of solar photocatalysis. • Ce22 presented improved performance in more complex matrices and E. coli disinfection.