Green synthesis and characterization of RGO/Cu nanocomposites as photocatalytic degradation of organic pollutants in waste-water

Recently, nanocomposite photocatalysts based on semiconductors have attracted much attention due to their suitable bandgap. Combination of tow of several semiconductors can slow down the electron-hole recombination. In this regard, we have depicted an eco-friendly and green fabrication technique to synthesize RGO/Cu nanocomposite by the reduction of graphene oxide and Cu²⁺ ion utilizing spearmint extract as a reductant and capping agent. The sample was identified by FTIR, XRD, FESEM, EDS, HRTEM, and CV. The results of photocatalytic performance revealed that RGO/Cu is an efficient catalyst for degrading organic pollutants. This compound can eliminate Rhodamine B (RhB) and Methylene blue (MB) 91.0% and 72.0%, respectively.     

Coupling CoFe2O4 and SnS2 nanoparticles with reduced graphene oxide as a high-performance electromagnetic wave absorber

The reduced graphene oxide (RGO)/CoFe₂O₄/SnS₂ composites have been successfully synthesized by two-step hydrothermal processes. TEM results show that CoFe₂O₄ and SnS₂ nanoparticles with both diameters about 5–10 nm are well dispersed on the surface of graphene. Compared with RGO/CoFe₂O₄ composites, the as-prepared RGO/CoFe₂O₄/SnS₂ composites exhibit excellent electromagnetic (EM) wave absorption properties in terms of both the maximum reflection loss and the absorption bandwidth. The maximum reflection loss of RGO/CoFe₂O₄/SnS₂ composites is −54.4 dB at 16.5 GHz with thickness of only 1.6 mm and the absorption bandwidth with the reflection loss below −10 dB is up to 12.0 GHz (from 6.0 to 18.0 GHz) with a thickness in the range of 1.5–4.0 mm. And especially, they cover the whole X band (8.0–12.0 GHz), which could be used for military radar and direct broadcast satellite (DBS).     

RGO-MIL-68(Fe)复合材料的静电自组装合成及光催化还原Cr(Ⅵ)的性能

采用静电自组装方法制备氧化石墨烯（GO）-MIL-68（Fe）复合物,并通过简单溶剂热处理,将GO还原为还原氧化石墨烯（RGO）,首次制得RGO-MIL-68（Fe）复合物。通过XRD、FESEM、紫外-可见漫反射光谱（UV-Vis DRS）等方法对RGO-MIL-68（Fe）复合催化剂的晶体结构、形貌、光吸收性能等物理化学性质进行表征。在可见光照射下,以草酸铵（（NH₄）₂C₂O₄）为牺牲剂,对RGO-MIL-68（Fe）复合材料进行光催化还原Cr（Ⅵ）性能评价,结果表明,只需复合少量的RGO,MIL-68（Fe）的光催化活性就能显著地提高。当RGO含量为1wt%时,RGO-MIL-68（Fe）复合材料表现出最优的光催化活性,反应60 min,体系中的Cr（Ⅵ）的还原率高达81%。结合电化学分析可知,这主要是由于RGO的引入在增强MIL-68（Fe）光吸收性能的同时也促进了光生载流子的分离。      

Efficient photothermal conversion of Fe2O3–RGO guided from ultrafast quenching effect of photoexcited state

In solar thermal utilization, effective photo capture and photothermal conversion are crucial. Improving the nonradiative transition rate of photoexcited electrons is important to enhance the photothermal conversion efficiency and develop efficient solar thermal utilization. Herein, we designed a new kind of light absorption-enhanced and efficient photothermal conversion material, namely, Fe₂O₃-functionalized reduced graphene oxide (Fe₂O₃–RGO). On the basis of the selective absorption (350–560 nm) of Fe₂O₃ and the synergistic effect of RGO on the quenching energy transfer of the excited state of Fe₂O₃ and ultrafast nonradiative thermal decay of RGO, the optical absorption capacity, and photothermal conversion efficiency of the composites were effectively improved. Fe₂O₃–RGO can be successfully applied to photothermal conversion phase change materials and seawater solar desalination, showing excellent photothermal conversion ability and application prospect.     

Ni-BTC/RGO复合材料的制备及其电化学性能EI北大核心CSCD

为了制备价格低廉且比电容高、循环稳定性好的电容器材料,采用电化学法合成石墨烯基含镍金属有机骨架材料Ni-BTC/RGO,研究含镍金属有机骨架材料Ni-BTC的合成条件以及Ni-BTC/RGO的电化学性能。对不同条件下的系列Ni-BTC材料进行XRD分析,并对Ni-BTC,RGO和Ni-BTC/RGO进行SEM测试、循环伏安测试和恒电流充放电测试。结果表明:工作电压为6 V、反应时间为3 h、反应体系温度为35℃是Ni-BTC的最佳合成条件;Ni-BTC和RGO成功复合且RGO对Ni-BTC的结构并未产生影响;复合材料主要表现赝电容电化学行为。在0.5 A·g^(-1)电流密度下,Ni-BTC/RGO的比电容为468.72 F·g^(-1),功率密度为0.249 W·g^(-1);在1.0 A·g^(-1)电流密度下循环500周次以后,比电容保留率为50.08%。     

Synthesis of cellulose/reduced graphene oxide/polyaniline nanocomposite and its properties

A series of conductive nanocomposites cellulose/reduced graphene oxide/polyaniline (cellulose/RGO/PANi) were synthesized via in situ oxidative polymerization of aniline on cellulose/RGO with different RGO loading to study the effect of RGO on the properties of nanocomposites. The results showed that when RGO is inserted into cellulose/PANi structure, its thermal stability and conductivity are increased. So that adding of only 0.3 wt% RGO into the cellulose/PANi structure, its conductivity is increased from 1.1 × 1 10^?1 to 5.2 × 110^?1 S/cm. Scanning electron microscopy results showed that the PANi nanoparticles are formed a continuous spherical shape over the cellulose/RGO template; this increases the thermal stability of nanocomposite.     

FeS2/RGO纳米复合材料的制备及热电池放电性能

以氯化亚铁、硫代硫酸钠和氧化石墨烯(GO)为原料, 采用水热法制备FeS₂/还原氧化石墨烯(RGO)纳米复合材料, 并采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、激光粒度分布仪和差热分析仪(DTA)等对FeS₂/RGO复合材料进行了表征。结果表明, 在水热反应过程中加入GO可以防止FeS₂颗粒的团聚, 使FeS₂形成疏松的球状颗粒。采用LiCl-KCl电解质, 在450℃以100mA/cm²电流密度放电时, 截止1.5 V时, FeS₂/RGO比容量为314.9 mAh/g, 较FeS₂高65.6 mAh/g; 采用LiF-LiCl-LiBr电解质, 在500℃以100 mA/cm²电流密度放电, 截止1.5 V时, FeS₂/RGO放电比容量为302.3 mAh/g, 较FeS₂高29.8 mAh/g。与FeS₂相比, 加入石墨烯提高了正极材料的导电性, 单体电池在放电过程中极化电阻相对较小, 使得FeS₂/RGO复合材料表现出较高的放电比容量。     

SnO2/还原氧化石墨烯/聚吡咯三元复合物的合成及其电化学电容性能

采用两步法制备出均匀分散的SnO2/还原氧化石墨烯(SnO2/RGO)二元复合物,再以二元复合物为模板,通过化学氧化法聚合吡咯(Py)单体,制备出SnO2/还原氧化石墨烯/聚吡咯(SnO2/RGO/PPy)三元复合材料。利用红外光谱(FTIR)、X射线衍射(XRD)和场发射扫描电镜(FESEM)对复合材料结构和形貌进行物性表征,利用循环伏安、恒电流充放电和交流阻抗对复合材料进行电化学性能研究,并讨论了不同含量的PPy对复合材料的结构和性能的影响。结果表明,所合成的三元复合材料的比电容随PPy含量的增加而增大,最大达到305.3F/g。三元复合物电容性能增强源于SnO2、RGO与PPy三者的相互协同作用,以及材料层状结构和大的比表面积。     

Bandgap control of p-n heterojunction of Cu–Cu2O @ ZnO with modified reduced graphene oxide nanocomposites for photocatalytic hydrogen evolution

Here, we describe the in-situ synthesis of multicomponent ZnO-based photocatalysts for hydrogen production. We fabricated ZnO coupled with Cu–Cu₂O nanoparticles and modified reduced graphene oxide (mRGO) to ameliorate hydrogen production. The simultaneous introduction of mRGO and Cu–Cu₂O enhanced the generation rate of photocatalytic hydrogen to 3085.02 μmol g^?1 h^?1 due to significant alteration of the electronic structure. The bandgap energy of the prepared catalysts decreased from 3.2 eV for pristine ZnO to 2.64 eV for a composite containing 15% Cu–Cu₂O. The optimal designed heterostructure efficiently separates photo charge carriers and prevents charge carriers’ recombination by accelerating charge transfer with the help of mRGO and metallic Cu and as a result leading to efficient hydrogen yields.     

RGO/MgO hybrid nanocomposites with high specific capacitance

A scalable, cost effective synthesis of reduced graphene oxide (RGO)-magnesium oxide (MgO) hybrid nanocomposite (RGOMOHNC) is reported in the present work. The process involves an in-situ sonication method in aqueous medium at room temperature e.g., 30 °C. The as synthesized graphene oxide (GO) and RGOMOHNC powders are characterized by the XRD, FESEM, TEM, FTIR, RS and XPS techniques. The results indicate that in-situ growth of 20–30 nm MgO nanoparticles effectively increases the graphitic nature of the layered RGO microstructure. The experimentally measured cyclic voltammetry (CV) plots show that the specific capacitance of the RGOMOHNC powders is three orders of magnitude higher than that of the GO powders. A mechanism of RGOMOHNC formation has been proposed.