The Influence of Dispersion State of Graphene Sheets on the Microstructure and Thermal Conductivity of Free-Standing Reduced Graphene Oxide Films

NANO ◽  
2019 ◽  
Vol 14 (03) ◽  
pp. 1950038 ◽  
Author(s):  
Xiaorui Wang ◽  
Shuangling Jin ◽  
Rui Zhang ◽  
Yan Liu ◽  
Jiangcan Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Hydrothermal Process ◽  
Weight Ratio ◽  
Atomic Ratio ◽  
Ammonia Solution ◽  
Free Standing ◽  
Reduced Graphene ◽  
Dispersion State

Reduced graphene oxide (rGO) aqueous dispersions were synthesized from GO suspensions with hydrazine as reducing agent via a microwave-hydrothermal process in ammonia solution. The rGO films were fabricated by vacuum filtration of above dispersions. When the weight ratio of hydrazine to GO (R[Formula: see text]) increases from 0.125 to 9, the dispersion stability of rGO nanosheets in hydrazine/ammonia solution degrades gradually, the surfaces of resultant films become rough from smooth and large interspaces turn up in the transverse section. With the increasing of R[Formula: see text], the C/O atomic ratio and orientation degree of (002) plane of rGO films increase, and the in-plane thermal conductivity also increases, achieving a maximum value of 1056[Formula: see text]W/m K when R[Formula: see text] is 3.375, then decreases because large interspaces in the rGO film with higher reduction degree greatly limit the thermal transport due to the severe phonon scatterings at the sheets boundaries.

Strongly Anisotropic Thermal Conductivity of Free-Standing Reduced Graphene Oxide Films Annealed at High Temperature

2015 ◽  
Vol 25 (29) ◽  
pp. 4664-4672 ◽  
Author(s):  
Jackie D. Renteria ◽  
Sylvester Ramirez ◽  
Hoda Malekpour ◽  
Beatriz Alonso ◽  
Alba Centeno ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
High Temperature ◽  
Reduced Graphene Oxide ◽  
Oxide Films ◽  
Free Standing ◽  
Anisotropic Thermal Conductivity ◽  
Reduced Graphene

scholarly journals Free-standing reduced graphene oxide (rGO) membrane for salt-rejecting solar desalination via size effect

Nanophotonics ◽  
2020 ◽  
Vol 9 (15) ◽  
pp. 4601-4608 ◽  
Author(s):  
Pengyu Zhuang ◽  
Hanyu Fu ◽  
Ning Xu ◽  
Bo Li ◽  
Jun Xu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Conversion Efficiency ◽  
High Salinity ◽  
Interlayer Spacing ◽  
Structural Instability ◽  
Solar Thermal ◽  
Free Standing ◽  
Solar Desalination ◽  
Reduced Graphene

AbstractInterfacial solar vapor generation has revived the solar-thermal-based desalination due to its high conversion efficiency of solar energy. However, most solar evaporators reported so far suffer from severe salt-clogging problems during solar desalination, leading to performance degradation and structural instability. Here, we demonstrate a free-standing salt-rejecting reduced graphene oxide (rGO) membrane serving as an efficient, stable, and antisalt-fouling solar evaporator. The evaporation rate of the membrane reaches up to 1.27 kg m−2 h−1 (solar–thermal conversion efficiency ∼79%) under one sun, out of 3.5 wt% brine. More strikingly, due to the tailored narrow interlayer spacing, the rGO membrane can effectively reject ions, preventing salt accumulation even for high salinity brine (∼8 wt% concentration). With enabled salt-antifouling capability, flexibility, as well as stability, our rGO membrane serves as a promising solar evaporator for high salinity brine treatment.

scholarly journals Boron from net charge acceptor to donor and its effect on hydrogen uptake by novel Mg-B-electrochemically synthesized reduced graphene oxide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marla V. V. Satya Aditya ◽  
Srikanta Panda ◽  
Sankara Sarma V. Tatiparti
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Incubation Time ◽  
Photoelectron Spectroscopy ◽  
Weight Ratio ◽  
Hydrogen Uptake ◽  
Binding Energies ◽  
Unit Cell ◽  
Net Charge ◽  
Reduced Graphene

AbstractHydrogen uptake (H-uptake) is studied in ball milled Mg-B-electrochemically synthesized reduced graphene oxide (erGO) nanocomposites at PH2 ≈ 15 bar, ~ 320 °C. B/C (weight ratio): 0, ~ 0.09, ~ 0.36, ~ 0.90 are synthesized maintaining erGO≈10wt %. B occupies octahedral interstices within Mg unit cell—revealed by electron density maps. Persistent charge donations from Mg and B to C appear as Mg-C (~ 283.2 eV), B-C (~ 283.3–283.9 eV) interactions in C-1s core X-ray photoelectron spectroscopy (XPS) at all B/C. At B/C > 0.09, charge reception by B from Mg yields Mg-B interaction. This net charge acceptor role of B renders it electron-rich and does not alter Mg unit cell size significantly. Despite charge donation to both C and B, the Mg charge is <  + 2, resulting in long incubation times (> 5 h) at B/C > 0.09. At B/C≈0.09 the minimal Mg-B interaction renders B a charge donor, resulting in Mg-B repulsion and Mg unit cell expansion. Mg-C peak shift to lower binding energies (C-1s XPS), decreases incubation time to ~ 2.25 h and enhances H-uptake kinetics. Various atomic interactions influence the reduction of incubation time in H-uptake and increase its kinetics in the order: (Mg → C; B → C)B/C≈0.09, B: donor > (Mg → C)B/C=0 > (ternary Mg → B → C)B/C>0.09, B: acceptor.

scholarly journals Simple synthesis of ZnO nanoparticles on N-doped reduced graphene oxide for the electrocatalytic sensing of l-cysteine

RSC Advances ◽  
2017 ◽  
Vol 7 (56) ◽  
pp. 35004-35011 ◽  
Author(s):  
Suling Yang ◽  
Gang Li ◽  
Chen Qu ◽  
Guifang Wang ◽  
Dan Wang
Keyword(s):  
Graphene Oxide ◽  
Low Temperature ◽  
Reduced Graphene Oxide ◽  
Zno Nanoparticles ◽  
Low Cost ◽  
Hydrothermal Process ◽  
Simple Synthesis ◽  
Zno Nanoparticle ◽  
Reduced Graphene ◽  
One Step

A new kind of ZnO nanoparticle/N-doped reduced graphene oxide nanocomposite (ZnONPs/N-rGO) was synthesized through a low temperature, low-cost and one step hydrothermal process.

Highly conductive free-standing reduced graphene oxide thin films for fast photoelectric devices

Carbon ◽  
2017 ◽  
Vol 115 ◽  
pp. 561-570 ◽  
Author(s):  
Hua Yang ◽  
Yang Cao ◽  
Junhui He ◽  
Yue Zhang ◽  
Binbin Jin ◽  
...  
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Oxide Thin Films ◽  
Free Standing ◽  
Reduced Graphene ◽  
Photoelectric Devices
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