Reduction of Graphene Oxide by Thiourea

Abstract

Various compounds with sulfur or diamine structure have been served as efficient reducing agents to convert graphene oxide to reduced graphene oxide. In this work, we used thiourea with both sulfur and diamine structure to synthesize reduced graphene oxide by the general wet chemical reduction method. The effective deoxygenation of graphene oxide was confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy analysis and Raman spectroscopy. The as-prepared reduced graphene oxide is consisted of few-layered (no more than seven) and over 60% single-layered graphene sheet determined by atomic force microscopy and transmission electron microscopy. It also exhibits good dispersion in organic solvents such as ethanol and N,N-dimethylformamide, which is useful for the further modification of graphene and preparation of novel nanocomposites. This newly found reducing agent is of low toxicity and nonvolatile, which makes the reduction much safer.

Enhanced Photocatalytic Hydrogen‐Production Performance of Graphene–ZnxCd1−xS Composites by Using an Organic S Source

“…Furthermore, the diamine structure of thiourea can also help to reduce GO to graphene. [33] Our preliminary experiments showed that, among pristine Zn x Cd 1Àx S solid solutions with different stoichiometries prepared by using thiourea as the S source, the Zn 0.5 Cd 0.5 S solid solution exhibited the highest H 2 -production rate. Therefore, Zn 0.5 Cd 0.5 S solid solution was used in the following study.…”

“…On the other hand, the amino groups in thiourea are activated by the C=S bonds, and thus thiourea molecules are grafted to the GO nanosheet through surface functional groups. [33] Thus, the metal cations (Zn 2+ and Cd 2 + ) and thiourea molecules tend to both be adsorbed on the surface of GO nanosheets through electrostatic attractions, and this leads to a predominantly heterogeneous nucleation process of ZCS NPs in the following reactions ( Figure 4). [38][39][40] Such in situ generation of ZCS NPs on graphene nanosheets facilitates close contact between the two phases, in agreement with Figure 2 a and b.…”

Synthesis, toxicity, biocompatibility, and biomedical applications of graphene and graphene-related materials

“…96,97 The most commonly used chemical reducing agents for the reduction of GO are hydrazine, [98][99][100][101] sodium borohydride, [102][103][104] Lawesson's reagent, 105 and thiourea. 106,107 Chemical reduction seems to be a very simple approach; however, it generates a graphene-like film containing low C:O ratio and a considerable quantity of residual functional groups, which leads to highly resistive film. [108][109][110] However, chemical reducing agents are toxic or explosive, resulting in challenges for large-scale production.…”

“…153 Ag-GO NPs may cause cell death by the following mechanisms: (i) GO could adhere to or wrap around E. coli through hydrogen bonds between the lipopolysaccharides of the bacteria and the oxygenated functional groups of GO. 107,152,155 (ii) GO could prevent uptake of nutrients from the surroundings while increasing the interaction between Ag NPs and the bacteria, 152 after which Ag NPs favor disruption of the bacterial membrane, leading to inhibition of respiration and replication of bacteria and eventually to cell death. 153,[155][156][157][158][159] (iii) The antibacterial effect of Ag-GO NPs could be caused by the "capturing-killing process", in which Ag-GO NPs contribute to the deposition of bacteria and increase the contact between the cells and the as-synthesized Ag NPs.…”

Synthesis and electrochemical properties of reduced graphene oxide via chemical reduction using thiourea as a reducing agent

“…Moreover the mechanism remains unclear. In view of this, the present investigation has been focussed on the use of thiourea as a reducing agent [16]. Compared to other reducing agents thiourea is less hazardous.…”