Metal-free graphene-carbon nitride hybrids for photodegradation of organic pollutants in water

Abstract

Hybrid photocatalysts of graphitic carbon nitride (g-C 3 N 4) and reduced graphene oxide (rGO) composites were prepared in one-pot via a thermal condensation of melamine with different amounts of graphene oxide (GO). As metal-free hybrids, the prepared photocatalysts presented enhanced performances in photooxidation of both methylene blue and phenol in water solutions under various light irradiations. The level of rGO significantly affected MB photodegradation efficiencies. The introduced graphene can improve the MB adsorption and optical absorption in visible light region, therefore enables the hybrids to efficiently degrade MB under visible light with wavelengths longer than 430 nm. The metal-free photocatalysts were also able to degrade phenol effectively and the effects of catalyst loading and initial phenol concentration were investigated. This study provided an efficient and environmentally benign photocatalyst for degradation of organic pollutants in water, with complete prevention of secondary contamination from metal-leaching.

Ordered Mesoporous C3N5 with a Combined Triazole and Triazine Framework and Its Graphene Hybrids for the Oxygen Reduction Reaction (ORR)

“…Forc omparison study,b ulk g-C 3 N 4 and bulk triazole-based C 3 N 5 were prepared using precursors of dicyandiamide and 5-ATTZ respectively without any KIT-6 or KIT-6-graphene templates. [11] TheM CN-11, MCN-11-G1, MCN-11-G2, MCN-11-G3, and MCN-11-G4 have chemical compositions of C 3 N 5.1 ·(H 2 O) 0.05 , C 3 N 5.1 ·(H 2 O) 0.05 -C 0.06 ,C 3 N 5.1 ·(H 2 O) 0.05 -C 0.12 ,C 3 N 5.1 ·(H 2 O) 0.05 -C 0.18 ,a nd C 3 N 5.1 ·(H 2 O) 0.05 -C 0.24 respectively,r evealing that Nrich C 3 N 5 and its graphene hybrids are successfully synthesized using the precursor of 5-ATTZ. [11] TheM CN-11, MCN-11-G1, MCN-11-G2, MCN-11-G3, and MCN-11-G4 have chemical compositions of C 3 N 5.1 ·(H 2 O) 0.05 , C 3 N 5.1 ·(H 2 O) 0.05 -C 0.06 ,C 3 N 5.1 ·(H 2 O) 0.05 -C 0.12 ,C 3 N 5.1 ·(H 2 O) 0.05 -C 0.18 ,a nd C 3 N 5.1 ·(H 2 O) 0.05 -C 0.24 respectively,r evealing that Nrich C 3 N 5 and its graphene hybrids are successfully synthesized using the precursor of 5-ATTZ.…”

“…[2b, 10] While graphene-free MCN-11 is bright yellow,M CN-11-G1, MCN-11-G2, MCN-11-G3, and MCN-11-G4 are green, indicating the successful hybridization of mesoporous C 3 N 5 and graphene ( Figure S1 in the Supporting Information). [11] TheM CN-11, MCN-11-G1, MCN-11-G2, MCN-11-G3, and MCN-11-G4 have chemical compositions of C 3 N 5.1 ·(H 2 O) 0.05 , C 3 N 5.1 ·(H 2 O) 0.05 -C 0.06 ,C 3 N 5.1 ·(H 2 O) 0.05 -C 0.12 ,C 3 N 5.1 ·(H 2 O) 0.05 -C 0.18 ,a nd C 3 N 5.1 ·(H 2 O) 0.05 -C 0.24 respectively,r evealing that Nrich C 3 N 5 and its graphene hybrids are successfully synthesized using the precursor of 5-ATTZ.…”

Enhanced Dispersibility of Graphitic Carbon Nitride Particles in Aqueous and Organic Media via a One-Pot Grafting Approach

“…6,7 As heterogeneous catalyst, it raised interest e.g. in CO 2 reduction, 8 water splitting, 9111 designed organic reactions, 12 photodegradation 13,14 and very recently as an amphiphile and Pickering emulsion1dispersion stabilizer. 15 The high chemical and thermal stability of g1CN as well as convenient synthesis and low cost precursors make it also a promising candidate for many photocatalytic applications.…”

Otimização da síntese de compósitos rGO/g-C>sub<3>/sub<N>sub<4>/sub< para a fotodegradação de poluentes orgânicos empregando-se o bisfenol A como modelo

“…Dentre os materiais lamelares estudados para a formação de heteroestruturas tipo II ativas sob luz visível, destaca-se o nitreto de carbono grafítico, g-C3N4, um sólido amarelo formado por uma estrutura lamelar bidimensional e polimérica de anéis derivados de unidades de s-triazina de grande extensão. Sua rota de síntese mais simples consiste na pirólise em atmosfera de ar, a partir de vários precursores, tais como a ureia e a melamina (AI et al, 2015;GAO et al, 2015;ALEKSANDRZAK;KUKULKA;MIJOWSKA, 2017;HAO et al, 2017;WEN et al, 2017).…”

“…ANTONIETTI, 2012;AI et al, 2015). Dessa forma, a busca por fotocatalisadores não metálicos principalmente baseados em estruturas derivadas de carbono, para a formação de heteroestruturas do tipo II, em particular, com o grafeno, vem chamando a atenção no campo da ciência dos materiaisLI et al, 2017;MASIH;ROHANI, 2017;NAVALON et al, 2017;XIAO et al, 2018b).2.3 Grafeno, Óxido de Grafeno e Óxido de Grafeno reduzidoO óxido de grafeno, GO, pode ser obtido a partir do grafite via condições oxidativas diversas.…”