Differently substituted aniline functionalized MWCNTs to anchor oxides of Bi and Ni nanoparticles

Abstract: We have studied the consequence of different functionalization types onto the decoration of multi-wall carbon nanotubes (MWCNTs) surface by nanoparticles of bismuth and nickel oxides. Three organic molecules were considered for the functionalization: 5-amino-1,2,3-benzenetricarboxylic acid, 4-aminobenzylphosphonic acid and sulfanilic acid. Nanotubes modification with in situ created diazonium salts followed by their impregnation with suitable salts [ammonium bismuth citrate and nickel (II) nitrate hexahydrate] utilizing infrared (IR) irradiation was found the crucial stage in the homogeneous impregnation of functionalized CNTs. Furthermore, calcination of these samples in argon environment gave rise to controlled decorated MWCNTs. The currently used technique is simple as well as effective. The synthesized materials were characterized by XPS, PXRD, FESEM, EDX, HRTEM and Raman spectroscopy. Bismuth oxide decorations were successfully performed using 5-amino-1,2,3-benzenetricarboxylic acid (particle size ranges from 1 to 10 nm with mean diameter ~ 2.4 nm) and 4-aminobenzylphosphonic acid (particle size ranges from 1 to 6 nm with mean diameter ~ 1.9 nm) functionalized MWCNTs. However, only 4-aminobenzylphosphonic acid functionalized MWCNTs showed strong affinity towards oxides of nickel nanoparticles (mainly in hydroxide form, particles size ranging from 1 to 6 nm with mean diameter ~ 2.3 nm). Thus, various functions arranged in the order of their increasing anchoring capacities are as follows: sulfonic < carboxylic < phosphonic. The method is valid for large-scale preparations. These advanced nanocomposites are potential candidates for various applications in nanotechnology. Graphic abstract: [Figure not available: see fulltext.].