title: Impact of Covalent Functionalization on the Aqueous Processability, Catalytic Activity, and Biocompatibility of Chemically Exfoliated MoS2Nanosheets.
abstract: Chemically exfoliated MoS2(ce-MoS2) has emerged in recent years as an attractive two-dimensional material for use in relevant technological applications, but fully exploiting its potential and versatility will most probably require the deployment of appropriate chemical modification strategies. Here, we demonstrate that extensive covalent functionalization of ce-MoS2nanosheets with acetic acid groups (∼0.4 groups grafted per MoS2unit) based on the organoiodide chemistry brings a number of benefits in terms of their processability and functionality. Specifically, the acetic acid-functionalized nanosheets were furnished with long-term (>6 months) colloidal stability in aqueous medium at relatively high concentrations, exhibited a markedly improved temporal retention of catalytic activity toward the reduction of nitroarenes, and could be more effectively coupled with silver nanoparticles to form hybrid nanostructures. Furthermore, in vitro cell proliferation tests carried out with murine fibroblasts suggested that the chemical derivatization had a positive effect on the biocompatibility of ce-MoS2. A hydrothermal annealing procedure was also implemented to promote the structural conversion of the functionalized nanosheets from the 1T phase that was induced during the chemical exfoliation step to the original 2H phase of the starting bulk material, while retaining at the same time the aqueous colloidal stability afforded by the presence of the acetic acid groups. Overall, by highlighting the benefits of this type of chemical derivatization, the present work should contribute to strengthen the position of ce-MoS2as a two-dimensional material of significant practical utility.
authors.affiliation: Instituto Nacional del Carbón, INCAR-CSIC , Apartado 73, 33080 Oviedo, Spain.
authors.forename: Juan I
authors.initials: JI
authors.lastname: Paredes
authors.affiliation: Instituto Nacional del Carbón, INCAR-CSIC , Apartado 73, 33080 Oviedo, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Munuera
authors.affiliation: Instituto Nacional del Carbón, INCAR-CSIC , Apartado 73, 33080 Oviedo, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Villar-Rodil
authors.affiliation: Instituto Nacional del Carbón, INCAR-CSIC , Apartado 73, 33080 Oviedo, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Guardia
authors.affiliation: Instituto Nacional del Carbón, INCAR-CSIC , Apartado 73, 33080 Oviedo, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Ayán-Varela
authors.affiliation: Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA) , Calle Mayor 1, 30150 La Alberca, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Pagán
authors.affiliation: Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA) , Calle Mayor 1, 30150 La Alberca, Spain.
authors.forename: Salvador D
authors.initials: SD
authors.lastname: Aznar-Cervantes
authors.affiliation: Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA) , Calle Mayor 1, 30150 La Alberca, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Cenis
authors.affiliation: Instituto Nacional del Carbón, INCAR-CSIC , Apartado 73, 33080 Oviedo, Spain.
authors.forename: Amelia
authors.initials: A
authors.lastname: Martínez-Alonso
authors.affiliation: Instituto Nacional del Carbón, INCAR-CSIC , Apartado 73, 33080 Oviedo, Spain.
authors.forename: Juan M D
authors.initials: JMD
authors.lastname: Tascón
keywords: MoS2; catalytic reduction; colloidal dispersion; functionalization; metal nanoparticles; transition metal dichalcogenides (TMDs); two-dimensional material