Heteroatom‐Doped Carbon Nanomaterials as Metal‐Free Catalysts for the Reduction of 4‐Nitrophenol

Abstract

In this work it is described the preparation and characterization of multi-walled carbon nanotubes and graphene flakes doped with heteroatoms, namely N, P, B, and S, through simple ball milling procedures with adequate precursors, followed by thermal treatments. Ball milling the carbon nanomaterials with melamine resulted in the introduction of pyrrolic, pyridinic and quaternary N atoms on the graphitic structure. Using triphenylphosphine as the phosphorous precursor induced the formation of RÀO-PO(OH) 2 functionalities. Materials prepared with boric acid showed the presence of boronic groups (C-BO 2 ) and B atoms in B 2 O 3 . S-doped materials presented tiophene-S type atoms. The catalytic studies showed that all the doped carbon materials were active catalysts in the reduction of 4-nitrophenol (4-NP), and that the modifications introduced by the doping procedures, overall yielded catalysts with superior activity in regard to their pristine counterparts. Reusability experiments revealed no loss of catalytic activity up to three catalytic cycles for the doped carbon nanotubes, whereas the graphene flake materials showed some deterioration of catalytic performance.

Ni/NiO Nanocomposites with Rich Oxygen Vacancies as High-Performance Catalysts for Nitrophenol Hydrogenation

“…Estimations show that a quarter of all chemical processes include at least one catalytic hydrogenation step [6]. Hydrogenation of nitrophenol (NP) to aminophenol is a typical reaction important for both environmental remediation and chemical stock production, considering that nitrophenols are hard-to-degrade compounds and exist widely in industrial wastewater [7]. The aminophenols are important intermediate products for synthesizing fine chemicals [8][9][10].…”

3D Hierarchical N, O Co–Doped MoS2/NiO Hollow Microspheres as Reusable Catalyst for Nitrophenols Reduction

“…It has been shown that the MoS 2 nanomaterials is catalytically active for the reduction of 4‐NP to 4‐AP . However, most of the reported MoS 2 nanomaterials are ultrathin nanosheets, which are difficult to recycle from solution.…”

“…It has been shown that the MoS 2 nanomaterials is catalytically active for the reduction of 4-NP to 4-AP. [27][28][29][30] However, most of the reported MoS 2 nanomaterials are ultrathin nanosheets, which are difficult to recycle from solution. Moreover, the catalytic activity is mainly from the edge sites rather than the basal sites, which result in lower catalytic efficiency.…”

Mechanochemical Routes to Functionalized Graphene Nanofillers Tuned for Lightweight Carbon/Hydrocarbon Composites

“…[101] Alternatively, hydrogen addition is used in mechanochemical reduction of graphene oxide. [102] Meanwhile an extraordinarily wide range of MFG bearing hydroxyl, carboxylic acid, halogen, five-,and six-membered N-heterocycles, sulfonic acid, and even phosphate groups have been prepared via graphite mechanochemistry in the presence of gases like CO 2 , [96,99] N 2 , [103,104] NH 3 , [105] H 2 , [106] O 2 , [100] Cl 2 , [107] F 2 , [107] and SO 2 , [99] liquids like Br 2 , [106,107] H 2 O, [108] SO 3 , [99,109] CO 2 /SO 3 , [99] as well as solids like red phosphorous, [110,111] sulfur, [112][113][114][115] melamine, [116][117][118][119] urea, [104,120,121] KOH, [122] NaCl, [123] Mg, [101] Fe, [124] Si, [125][126][127] polystyrene, [128] cellulose, [64] chitin, [129] polyvinylpyrrolidone, [130] polyetherketone, [131] and I 2 . [106,…”

“…Meanwhile an extraordinarily wide range of MFG bearing hydroxyl, carboxylic acid, halogen, five‐ ,and six‐membered N ‐heterocycles, sulfonic acid, and even phosphate groups have been prepared via graphite mechanochemistry in the presence of gases like CO 2 , N 2 , NH 3 , H 2 , O 2 , Cl 2 , F 2 , and SO 2 , liquids like Br 2 , H 2 O, SO 3 , CO 2 /SO 3 , as well as solids like red phosphorous, sulfur, melamine, urea, KOH, NaCl, Mg, Fe, Si, polystyrene, cellulose, chitin, polyvinylpyrrolidone, polyetherketone, and I 2 . The applications of MFGs spans from catalysts to energy material systems and polymer nanocomposites .…”