Non-covalent Functionalization of Graphene to Tune Its Band Gap and Stabilize Metal Nanoparticles on Its Surface

Abstract

Controlling graphene conductivity is crucial for its potential applications. With this focus, this paper shows the effect of the non-covalent bonding of a pyrimidine derivative (HIS) on the electronic properties of graphene (G). Several G-HIS hybrids are prepared through mild treatments keeping unaltered the structures of both G and HIS. The attachment of HIS to G occurs by π–π stacking of the HIS-aromatic residue with the G surface. This partially blocks the p z electrons of G, giving rise to the splitting of both the valence and conduction bands. Moreover, the width of the splitting is directly related to the HIS content. This fact allows the fine-tuning of the band gap of G-HIS hybrids. Furthermore, HIS keeps its metal-complexing ability in the G-HIS hybrids. Taking advantage of this, a G-HIS–Cu(0) composite was prepared by H 2 plasma reduction of a precursor of the G-HIS–Cu(II) type. G-HIS−Cu(0) contains Cu(0) clusters stabilized on the G surface due to interactions with the COO – functions of HIS. In an analogous hybrid, G-HIS–Au(0), the Au(0) NPs are also stabilized by COO – functions. This material, consisting of the coupling of Au(0) NPs and G-HIS, photocatalyzed water reduction under visible light radiation producing 12.5 μmol·g –1 ·h –1 of hydrogen.

Covalent organic functionalization of graphene nanosheets and reduced graphene oxidevia1,3-dipolar cycloaddition of azomethine ylide

“…[52][53][54][55][56][57] In contrast, the non-covalent chemical modication is oen realized by intermolecular interactions such as van der Waals forces, 58 electrostatic interactions, 59 or p-p stacking interaction. [60][61][62] In particular, the covalent functionalization of graphene sheets using organic functional groups has been explored as a pivotal step towards the formation of graphene composites at the nanoscale. A commonly diffuse approach is the use of diazonium salts, oen done through electrochemical or heating processes.…”

Noncovalent Assembly and Catalytic Activity of Hybrid Materials Based on Pd Complexes Adsorbed on Multiwalled Carbon Nanotubes, Graphene, and Graphene Nanoplatelets

“…Both GNPT-L1-Pd and GNPT-L2-Pd were prepared using, as a carbon support, commercial GNPTs with an average diameter (<1.5 μm) 5 times lower than that of G. 54 The preparation was carried out by following a two-step procedure similar to that described in the previous section for MWCNT-L1-Pd and G-L2-Pd. Notably, the maximum adsorption capacities of L1 and L2 on the used GNPTs are significantly higher than those on G, especially in the case of L2 (L2, 0.82 mmol g –1 ; L1, 0.55 mmol g –1 ).…”

“…Before use, it was suspended in water under stirring for 24 h to remove the labile oxygen groups and then separated by filtration and air-dried. Characterization data of the obtained material, G, were published previously. ,, …”

“…Characterization data of the obtained material, G, were published previously. 52,54,55 Commercial multiwalled carbon nanotubes (MWCNTs) were purchased from NanoAmor (USA). According to the data from the supplier, the product has an outside diameter of 8−15 nm, an inside diameter of 3−5 nm, and lengths of between 10 and 50 μm.…”

Covalent Organic Functionalization of Graphene Nanosheets and Reduced Graphene Oxide via 1,3-Dipolar Cycloaddition of Azomethine Ylide

“…[52][53][54][55][56][57] In contrast, the non-covalent chemical modification is often realized by intermolecular interactions such as van der Waals forces, 58 electrostatic interactions, 59 or π − π stacking interaction. [60][61][62] In particular, the covalent functionalization of graphene sheets using organic functional groups has been explored as a pivotal step towards the formation of graphene composites at the nanoscale. A commonly diffuse approach is the use of diazonium salts, often done through electrochemical or heating processes.…”