Surface Of Reduced Graphene Oxide Research Articles

Electrocatalytic degradation of naphthenic acids using reduced graphene oxide modified nickel foam cathode: Role of surface structure and superoxide radical

In this work, the reduced graphene oxide (RGO) modified nickel foam (Ni-foam) was prepared via the hydrothermal reduction self-assembly method and was applied as the cathode for the effective electrocatalytic (EC) degradation of recalcitrant naphthenic acids (NAs) that are abundantly present in the petroleum industrial wastewater. The Ni@RGO cathode has greatly enhanced the production of H2O2 in the system to boost the degradation of 1-adamantanecarboxylic acid (ACA) that was a model NA compound. Results showed that the EC/Fe(III)/Ni@RGO system achieved complete ACA degradation within 15 min due to its elevated H2O2 generation and Fe(III)/Fe(II) circulation, compared to EC/Fe(III)/Ni-foam and EC/Fe(III)/Graphite systems. Interestingly, abundant ·O2– radicals, which were produced in EC/Fe(III)/Ni@RGO system as a key intermediate for 2e- oxygen reduction reaction (ORR), could effectively accelerate the circulation of Fe(III)/Fe(II) to activate H2O2 to generate ·OH for ACA degradation. Results of material characterization, electrochemical analysis and density functional theory (DFT) calculations showed that Ni@RGO cathode has obtained elevated electron transfer efficiency compared to that of Ni-foam cathode. Surface structure of RGO, such as carbon edge and vacancy with specific configuration, residual –COOH oxygenation groups on RGO surface are main catalytic sites to enhance the capacity of 2e- ORR and electron capture processes in the system. This study provides new insights regarding the synthesis process of catalytic electrodes, the influence of carbon-based material structure on catalytic activity, and the critical role of free radicals in the electro-Fenton system with Ni@RGO cathode.

Palladium–reduced graphene oxide nanocomposites enhance neurite outgrowth and protect neurons from Ishemic stroke

Currently, the construction of novel biomimetic reduced graphene oxide (RGO)-based nanocomposites to induce neurite sprouting and repair the injured neurons represents a promising strategy in promoting neuronal development or treatment of cerebral anoxia or ischemia. Here, we present an effective method for constructing palladium-reduced graphene oxide (Pd-RGO) nanocomposites by covalently bonding Pd onto RGO surfaces to enhance neurite sprouting of cultured neurons. As described, the Pd-RGO nanocomposites exhibit the required physicochemical features for better biocompatibility without impacting cell viability. Primary neurons cultured on Pd-RGO nanocomposites had significantly increased number and length of neuronal processes, including both axons and dendrites, compared with the control. Western blotting showed that Pd-RGO nanocomposites improved the expression levels of growth associate protein-43 (GAP-43), as well as β-III tubulin, Tau-1, microtubule-associated protein-2 (MAP2), four proteins that are involved in regulating neurite sprouting and outgrowth. Importantly, Pd-RGO significantly promoted neurite length and complexity under oxygen-glucose deprivation/re-oxygenation (OGD/R) conditions, an in vitro cellular model of ischemic brain damage, that closely relates to neuronal GAP-43 expression. Furthermore, using the middle cerebral artery occlusion (MCAO) model in rats, we found Pd-RGO effectively reduced the infarct area, decreased neuronal apoptosis in the brain, and improved the rats’ behavioral outcomes after MCAO. Together, these results indicate the great potential of Pd-RGO nanocomposites as a novel excellent biomimetic material for neural interfacing that shed light on its applications in brain injuries.

Synthesis of reduced graphene oxide and its application for the removal of anaionic dye TURQUOISE GN

Although graphene oxide (GO) and its derivatives showed excellent adsorption capacities for dyes and heavy metals, its application is limited to cationic and commercially used dyes. In this article reduced graphene oxide (RGO) was prepared and applied for the adsorption of a commercially used anionic dye. GO was prepared from graphite powder by modified Hummer’s method and reduced to RGO by hydrazine hydrate. Characterization of prepared RGO was carried out by Raman spectroscopy, ESEM, XRD, elemental analysis and the surface charge was determined by zeta potential analysis. An anionic dye TURQUOISE GN (TGN) was used to investigate the adsorption capacity of prepared RGO. To know the adsorption properties of RGO, the effects of solution pH, dosage of adsorbent, concentration of the dye, adsorption time and temperature on adsorption capacity of RGO were also studied. The distribution of the adsorbate on the RGO surface was studied with both Langmuir and Freundlich isotherm models and it was found that it preferably followed Langmuir model. The theoretical maximum adsorption capacity was found to be 588.24 mg/g at pH 7. To find out the mechanism of the adsorption of TGN on RGO pseudo-first-order and pseudo-second order kinetic models were applied and the results fitted perfectly with the second-order kinetic model. The exhausted RGO was regenerated by treating with 2 % HCl followed by washing with demineralized water and showed moderate adsorption capacity.

In-situ generation of enhanced Pd-Co nanoparticles using various stabilizing agents decorated on reduced graphene oxide as electrocatalyst for oxygen reduction reaction

The synthesis and characterization of PdCo nanoparticles deposited on reduced graphene oxide as an electrocatalyst for the oxygen reduction reaction have been successfully carried out. This research aims to investigate the influence of various stabilizing agents on the character of the metal nanoparticles towards the activity of the oxygen reduction reaction (ORR). Reduced graphene oxide (RGO) acts as a supporting material for the PdCo nanoparticles. This material was produced from graphite as a raw material that was oxidized using the Tour method. The PdCo/RGO material was synthesized by in-situ generation with the various stabilizing agent types of cetyltrimethylammonium bromide (CTAB), hexamethylenetetramine (HMTA) and a combination of CTAB-HMTA. The results showed that the optimal stabilizing agent type for PdCo/RGO is HMTA (PdCo-H/RGO), giving PdCo nanoparticles with the smallest size, the most uniform shape and the most dispersion on the RGO surface. The ORR catalytic test showed that PdCo-H/RGO displayed activity, with the number of electron transfers being 3.64, which follows the direct 4-electron reduction pathway of the ORR. The catalyst stability test showed that PdCo-H/RGO had relatively high durability with an E1/2 negative shift of 57.6 mV.

Synthesis, characterization, and FDTD simulations of Ag-enriched RGO nanosheets for catalytic reduction of 4-nitrophenol

Reduced graphene oxide-based nanocomposites are eminent materials having diverse applications including environmental remediation. The present work emphasizes the facile one-step co-reduction method for synthesizing silver nanoparticle (Ag NPs) decorated reduced graphene oxide (RGO) for catalytic reduction of 4-nitrophenol. FDTD simulation studies justify the experimental results, and XRD studies confirmed the reduction of graphene oxide and the formation of Ag NPs with reduced graphene oxide (AgRGO) composite. Raman analysis complements the structure, crystallinity, and defects in the fabricated material. XPS analysis verifies the reduction of graphene oxide (GO) into RGO and the decoration of metallic Ag on the surface of RGO. FESEM image showed the decoration of Ag NPs on the surface of RGO. AgRGO exhibited appreciable catalytic performance for reducing 4-nitrophenol in the presence of sodium borohydride compared to GO and RGO.

‘Ball-on-plane’ ZnS@RGO compound filler: effect on tribological properties of thermosetting polyimide film

ABSTRACT In this study, a compound filler consisting of zinc sulfide (ZnS) nanoparticles and reduced graphene oxide (RGO) was synthesized using the hydrothermal method and utilized to enhance the tribological properties of the polyimide (PI) film. The ZnS@RGO/PI composites displayed the lowest wear rate of 3.89 × 10−8 mm3 N−1 m−1 at a load of 200 N, which were significantly lower than that of both pure PI and RGO/PI films. Furthermore, the microstructure and chemical composition of the compound were characterized and analyzed, revealing that the ZnS nanoparticles were effectively attached to the surface of RGO through the chemical bonding between them. Finally, finite element analysis shows that the chemical bonding between ZnS and RGO have the effect to stop the crack expanding under pressure, and a wear mechanism is also given to demonstrate this ‘Ball-on-plane’ compound’s enhancement to the tribological properties.

The adsorption of tetracycline, ciprofloxacin on reduced graphene oxide surfaces: Role of intermolecular interaction

In this study, the adsorptions of tetracycline (TC) and ciprofloxacin (CIP) molecules on different surfaces of reduced graphene oxide (rGO) are investigated by using quantum chemical calculations. Our results reveal stable configurations for both the molecules, rGO surfaces, and their complexes, highlighting the favorable arrangements of TC and CP on the rGO surfaces, which facilitates intermolecular interactions at functional group sites such as -O-, –OH, >CO, and –COOH. While the physical adsorption is observed for TC and CIP molecules on the rGO surface, the introduction of Ca2+ cation promotes chemical adsorption of these molecules on rGO. It is noticeable that the adsorption of TC and CIP on Ca2+-supported rGO is stronger of five times than on rGO surfaces. Importantly, our findings demonstrate that the adsorption affinity of TC is higher than that of CIP on both the pristine rGO and Ca2+-supported surfaces. The existence and role of surface interactions are further elucidated through AIM and NBO analyses, revealing an essential role of O/N/CH‧‧‧O hydrogen bonds in stabilizing configurations of TC and CIP on the rGO surface models. Notably, the presence of Ca‧‧‧O attractive electrostatic interaction enhances the stability of the adsorption configuration on the Ca2+-supported rGO surface. These insights emphasize the potential usage of rGO-based materials in the adsorption of antibiotic molecules for various environmental related applications.

Effect of Fe3O4:RGO Ratios in Magnetic Nanocomposites Applied for Dye Discoloration

Nanocomposites of magnetite anchored on reduced graphene oxide with different magnetite:reduced graphene oxide mass ratios were synthesized and evaluated in indigo carmine photo Fenton discoloration. All nanocomposites are magnetic and showed comparable amounts of magnetite and hematite with a higher level of hematite for low iron contents. The highest value of 63.6 emu g-1 was obtained for the nanocomposite with the highest magnetite content. The nanocomposites presented high dispersion of iron oxide particles, at about 12 nm on reduced graphene oxide surface sheets. The samples also showed bandgap energies below that found for bulk magnetite, showing an important effect of reduced graphene oxide. The nanocomposite with an iron nitrate precursors mass ratio of 17:1 showed the best performance (99.7% of indigo carmine discoloration (2.1 × 10-5 mol L-1) at 30 min of reaction, hydrogen peroxide(2.3 × 10-1 mol L-1), and a catalyst dosage of 0.67 g L-1). Reusability tests were performed, and this nanocomposite was shown to be active for at least three recycles. X-ray photoelectron spectrum of Fe2p3/2 showed that the FeIII/FeII ratio was maintained even after three recycles (4 runs), meaning that reduced graphene oxide is responsible for stabilizing magnetite particles, thus maintaining its photocatalytic activity.

Insitu assembly of Fe3O4@FeNi3 spherical mesoporous nanoparticles embedded on 2D reduced graphene oxide (RGO) layers as protective barrier for EMI pollution

Electromagnetic interference (EMI) is a major issue due to the increased use of electronic devices operating in the gigahertz frequency range. Consequently, to reduce electromagnetic pollution, materials with considerable magnetic and dielectric loss can be used for the attenuation of electromagnetic waves. In this paper, Fe3O4 FeNi3 spherical mesoporous nanoparticles embedded on reduced graphene oxide (RGO) layers have been synthesized using the hydrothermal reduction method. The specific surface area of Fe3O4@FeNi3/RGO nanocomposite was 67.4 m2/g with a pore size diameter of 3.4 nm (i.e., mesoporous range). Fe3O4@FeNi3/RGO nanocomposites show an enhanced absorption dominant shielding effectiveness (SE) value of 46.49 dB as compared to its binary counterpart Fe3O4@FeNi3, having SE value of 25.21 dB. The synthesized Fe3O4@FeNi3/RGO nanocomposite of thickness 1.42 mm has SER of ∼10.32 dB and SEA of ∼36.15 dB at 15 GHz. Furthermore, it is observed that shielding efficiency increases with increasing reduced graphene oxide (RGO) content in Fe3O4@FeNi3, which is owing to an excellent interconnected network between RGO and Fe3O4@FeNi3. The RGO sheets can create a comprehensive conductive network for the distribution of charges and can enhance dielectric loss because of the layered structure, greater specific surface area and large aspect ratio. Additionally, the mesoporous Fe3O4@FeNi3 hybrid embellished on the surface of RGO may be employed as a multi-pole polarisation centre, enhancing the electronic and space charge polarization of the composites, which is helpful for strong EM wave absorption. It was believed that these nanocomposites would pave the way for the development of RGO-based mesoporous nanocomposites as broadband, lightweight and effective shielding material for practical applications.

Efficient formic acid oxidation over gallium oxide incorporated Pd containing electrocatalyst

In this work, a highly efficient Pd catalyst containing gallium oxides supported on reduced graphene oxides has been synthesized by sodium borohydride reduction method for the electro-oxidation of formic acid. The synthesized PdxGay/rGOs display outstanding electrocatalytic activity with considerably higher surface area and improved electrical conductivity during formic acid oxidation as compared to Pd/C. According to the electrochemical results the Pd6Ga4/rGO showed significantly higher electrochemical surface area (102.4 m2/g), improved catalytic activity (86 mA/cm2), smaller Tafel slope value (121 mV dec−1) and excellent durability during the electrocatalytic formic acid oxidation. Th higher turnover frequency of Pd6Ga4/rGO (4.2 × 10−1) further validates its better electrocatalytic activity. This work proves that adding gallium oxides to palladium-based electrocatalysts increases electrical conductivity and causes the uniform dispersion of palladium nanoparticles on reduced graphene oxide surface.

Efficient solar-driven carbon dioxide capture system for greenhouse using graphene-contained deep eutectic solvents

As photosynthesis progresses, the concentration of CO2 within greenhouses rapidly declines, significantly impairing crop growth. In light of the prevailing limitations associated with complex systems, high energy consumption, and safety concerns related to existing CO2 supplementation methods, a novel “solar-driven CO2 capture system” was proposed for the first time in current work, in which high photothermal conversion materials were incorporated into the deep eutectic solvents (DES). This nanofluid system aims to elevate the system's temperature, facilitating the desorption process and promoting the CO2 absorption–desorption cycle. The graphene nanofluid (GNF) prepared with varying mass fractions of reduced graphene oxide (RGO) can raise CO2 absorption capacity. The results indicate that the CO2 absorption capacity has improved from 0.286 g/g to 0.399 g/g, which can be attributed to abundant adsorption sites provided by the surface of RGO for capturing CO2. Furthermore, the addition of RGO improves the photothermal conversion performance of DES. Maximum photothermal conversion efficiency of 94.3 % and a maximum temperature of 75.9℃ have been achieved for DES-500 (with the addition of 500 ppm RGO in DES) under the irradiation of 1000 W/m2; while pure DES presents 32.7 % and 54.7℃, respectively. Notably, GNF also exhibits excellent recyclability and can effectively regulate CO2 concentration within the greenhouse, ensuring normal growth and development of crops.

Ni Nanoparticles on the Reduced Graphene Oxide Surface Synthesized in Supercritical Isopropanol.

Nanocomposites based on ferromagnetic nickel nanoparticles and graphene-related materials are actively used in various practical applications such as catalysis, sensors, sorption, etc. Therefore, maintaining their dispersity and homogeneity during deposition onto the reduced graphene oxide substrate surface is of crucial importance to provide the required product characteristics. This paper demonstrates a new, reproducible method for preparing a tailored composite based on nickel nanoparticles on the reduced graphene oxide surface using supercritical isopropanol treatment. It has been shown that when a graphene oxide film with previously incorporated Ni2+ salt is treated with isopropanol at supercritical conditions, nickel (2+) is reduced to Ni (0), with simultaneous deoxygenation of the graphene oxide substrate. The resulting composite is a solid film exhibiting magnetic properties. XRD, FTIR, Raman, TEM, and HRTEM methods were used to study all the obtained materials. It was shown that nickel nanoparticles on the surface of the reduced graphene oxide had an average diameter of 27 nm and were gradually distributed on the surface of reduced graphene oxide sheets. The data obtained allowed us to conduct a reconnaissance discussion of the mechanism of composite fabrication in supercritical isopropanol.

Green synthesis of recyclable reduced graphene oxide-gold nanocatalyst using Alstonia scholaris: Applications in waste water purification and microbial field

The green synthetic approaches are the alternative methods for the preparation of various types of nanoparticles to keep sustainable evolution. A novel green synthesis of gold- reduced graphene oxide nanocomposites was conducted through simple heating method using Alstonia scholaris (A. scholaris) bark extract. There are several techniques that confirm the formation of the nanocomposites for synthesis of gold nanoparticles on reduced graphene oxide (RGO), such as X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis) and Fourier transformed infrared spectroscopy (FT-IR). The size distributions of the gold nanoparticles (Au NPs) grown on RGO surface was measured using two different methods: particle distribution study and transmission electron microscopy (TEM) image. These two methods provided similar size distribution which is around 5–8 nm. Subsequently, the catalytic performance was evaluated by 4-nitro aniline (4-NA). The photocatalytic activities were investigated using different organic hazardous dyes, such as methylene blue (MB), methyl orange (MO) and the change of photocatalytic behaviour was shown by varying the catalyst amount and pH. The chemical oxygen demand (COD) analyses for complete removal of organic dye were carried out using the two nanocomposite samples. To perceive the effect on different bacterial strains, antibacterial and antiprotozoal studies have been carried out with this nanocomposite.

Facile sonochemical synthesis of nanostructured FeWO4-rGO and CuCo2O4 nanocomposite for high-rate capability and stable asymmetric (CuCo2O4//FeWO4-rGO) supercapacitors

The present work reports iron tungstate (FeWO4) nanostructures with reduced graphene oxide (rGO) as a novel anode material for enhancing the electrochemical properties of asymmetric supercapacitors. The FeWO4-rGO composite nanostructures were successfully synthesized by the one-pot sonochemical method. The synthesized nanocomposites crystal structure and phase purity were investigated using the powder X-ray diffraction (XRD) technique. The Fourier transform infrared (FT-IR) spectrograms demonstrate the presence of functional groups in the composite. The composite's morphology was examined using the high-resolution transmission electron microscopy (HR-TEM) and the field emission scanning electron microscopy (FE-SEM), and it was observed that the FeWO4 nanostructures were uniformly distributed on the reduced graphene oxide surface. The cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) analyses were used to evaluate the electrochemical performance. After 5000 cycles at 10 mA cm− 2, the FeWO4-rGO composite achieved a better rate of efficiency and outstanding cycling performance, with capacitance retained at 68% and 77.8%, respectively. In 1 M Na2SO4, an asymmetric device (CuCo2O4//FeWO4-rGO composite) achieved a high energy density of 21.5 W.h Kg−1 and a power density of 147 W Kg−1. In the FeWO4-rGO nanocomposite, the reduced graphene oxide could enhance the conductivity and the free diffusion processes for the quick ion transport and easy ion access to the storage sites. The obtained results indicated that the FeWO4-rGO nanocomposite could be a good anode electrode material for the next-generation energy storage applications.

Graphene modification with chrysin molecules as a high performance electrode material for supercapacitor

In this study, chrysin (CHY) molecules are immobilized on the surfaces of graphene oxide (GO) via π-π interactions to obtain organic molecular-modified reduced graphene oxide (RGO) composite electrode material (CHY/RGO) by one-step hydrothermal. On one hand, CHY molecules can contribute to capacitance through faradic reactions. On the other hand, they act as spacers that impede the accumulation of graphene nanosheets and promote electrolyte ion migration. As a result, CHY/RGO exhibits excellent capacitance performance. The specific capacitance is up to 707F g−1 (1 A g−1), and the capacitance remains 100% after 10 000 circles. In addition, the symmetrical supercapacitor (CHY/RGO//CHY/RGO) displays excellent energy storage performance, achieving an energy density of 38 Wh kg−1 at a power density of 800 W kg−1. Two CHY/RGO//CHY/RGO devices in series is capable of lighting 50 LEDs. Density functional theory (DFT) calculations show that CHY molecules are adsorbed parallel to the RGO by the π-π stacking. The DFT calculations also indicate that the modification of CHY molecules alters the charge distribution on the surface of RGO. Therefore, CHY/RGO composites offer a higher capacitance and superior cycle stability, making them a promising choice for future energy storage electrode materials.

Structural and chemical engineering of metal-organic framework-derived nickel disulfide nanosheets as the compacted cathode matrix for lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries are recognized as promising high-energy-density storage systems. It is crucial to develop the compacted sulfur cathodes with high sulfur content and high sulfur loading for practical applications. The metal-containing nanosheets are promising cathode matrix to mediate the accompanying problems, such as low sulfur utilization, unavoidable polysulfides shuttling and poor rate performance. Herein, we develop Ni-MOF-based strategy to fabricate nickel disulfide nanosheets on the reduced graphene oxide surface (NSG). Benefiting from nanosheets structure, strong polysulfides affinity, high electronic conductivity and superior electrocatalytic effect of NSG heterostructure, the resultant electrode exhibits high electrochemical performance with 0.021% capacity decay per cycle in 1000 cycles. Remarkably, the electrode with 88 wt% sulfur content and 5.9 mg cm−2 sulfur loading delivers reversible capacity of 945 mA h g−1, areal capacity of 6.1 mA h cm−2 and volumetric capacity of 997 mA h cm−3 at 0.5 C, which is comparable with the state-of-the-art those in the reported energy storage systems. This work provides methodology guidance for the development of cathode matrix to achieve high-energy-density and long-life Li–S batteries.

Nanogold-decorated reduced graphene oxide for catalytic hydrogenation of 4-nitrophenol

The current work focuses on the efficacious synthesis of Au nanoparticles (NPs) decorated on reduced graphene oxide (RGO) sheets and evaluating and comparing the catalytic efficiency of the latter with graphene oxide (GO) and reduced graphene oxide (RGO) for the hydrogenation of 4-nitrophenol (4-NP). 4-NP is one of the most hazardous and widely investigated nitro compounds. Here, we report a single-step co-reduction approach for synthesizing AuRGO using hydrazine monohydrate as a reducing agent. X-ray diffraction (XRD) patterns of prepared samples confirmed the formation of GO, RGO, and AuRGO. Raman analysis gave insight into the structure and defects of prepared samples. The various oxygen-containing moieties are identified using Fourier transform infrared (FTIR) spectra and confirmed the loss of these functional groups during the reduction of GO into RGO. UV absorption analysis is carried out and is also reinforced by the finite difference time domain (FDTD) simulation studies. X-ray photoelectron spectroscopy (XPS) analysis yielded quantitative information regarding the reduction of GO into RGO and the decoration of zerovalent Au NPs on the RGO surface. Thermogram of the prepared samples manifests the thermal stability of the samples. Field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) images depicted the morphology of GO, RGO, and AuRGO. The catalytic efficiency of AuRGO is tested by reducing 4-nitrophenol (4-NP) in the presence of sodium borohydride. AuRGO has shown enhanced catalytic efficiency compared to GO and RGO.

Photocatalytic Degradation of Methylene Blue and Anticancer Response of In2O3/RGO Nanocomposites Prepared by a Microwave-Assisted Hydrothermal Synthesis Process.

The incorporation of graphene with metal oxide has been widely explored in various fields, including energy storage devices, optical applications, biomedical applications, and water remediation. This research aimed to assess the impact of reduced graphene oxide (RGO) doping on the photocatalytic and anticancer properties of In2O3 nanoparticles. Pure and In2O3/RGO nanocomposites were effectively synthesized using the single-step microwave hydrothermal process. XRD, TEM, SEM, EDX, XPS, Raman, UV-Vis, and PL spectroscopy were carefully utilized to characterize the prepared samples. XRD data showed that synthesized In2O3 nanoparticles had high crystallinity with a decreased crystal size after RGO doping. TEM and SEM images revealed that the In2O3 NPs were spherical and uniformly embedded onto the surface of RGO sheets. Elemental analysis of In2O3/RGO NC confirmed the presence of In, O, and C without impurities. Raman analysis indicated the successful fabrication of In2O3 onto the RGO surface. Uv-Vis analysis showed that the band gap energy was changed with RGO addition. Raman spectra confirmed that In2O3 nanoparticles were successfully anchored onto the RGO sheet. PL results indicated that the prepared In2O3/RGO NCs can be applied to enhance photocatalytic activity and biomedical applications. In the degradation experiment, In2O3/RGO NCs exhibited superior photocatalytic activity compared to that of pure In2O3. The degradation efficiency of In2O3/RGO NCs for MB dye was up to 90%. Biological data revealed that the cytotoxicity effect of In2O3/RGO NCs was higher than In2O3 NPs in human colorectal (HCT116) and liver (HepG2) cancer cells. Importantly, the In2O3/RGO NCs exhibited better biocompatibility against human normal peripheral blood mononuclear cells (PBMCs). All the results suggest that RGO addition improves the photocatalytic and anticancer activity of In2O3 NPs. This study highlights the potential of In2O3/RGO NCs as an efficient photocatalyst and therapeutic material for water remediation and biomedicine.

Photocatalytic degradation of naphthol blue from Batik wastewater using functionalized TiO2-based composites

This work provides a first-time comparative study examining the photocatalytic activity of functionalized TiO2-based composites to eliminate naphthol blue in Batik wastewater. Reduced graphene oxide (RGO) was synthesized by oxidizing solid graphite using the Hummers' method followed by sonication and reduction. N-doped TiO2 (N–TiO2) was synthesized from titanium tetrachloride (TiCl4) and urea (CH₄N₂O) precursors by the sol-gel method. N–TiO2 modified RGO (RGO/NT) was synthesized using a hydrothermal method from N–TiO2 and RGO. Prepared TiO2-based composites and commercial TiO2, for comparison were characterized using Fourier transform infrared spectrometer (FTIR), X-Ray diffractometer (XRD), scanning electron microscope-energy dispersive X-ray (SEM-EDX), and UV–Vis diffuse reflectance spectrometer (UV–Vis DRS). FTIR characterization indicated Ti–N bonding in N–TiO2 and RGO/NT. XRD patterns showed that commercial TiO2 had a rutile phase, while N–TiO2 and RGO/NT had an anatase phase with crystal sizes of 30.09, 16.28, and 12.02 nm, respectively. SEM results displayed the presence of small and glossy white N–TiO2 dispersed on the surface of RGO. Characterization using UV–Vis DRS showed that the band gap energy values for TiO2, N–TiO2, and RGO/NT were 3.25, 3.12, and 3.08 eV with absorption regions at the wavelengths of 382, 398, and 403 nm, respectively. The highest photocatalytic activity for RGO/NT for degrading naphthol blue was obtained at pH 5, with a photocatalyst mass of 60 mg, and an irradiation of 15 min. Photocatalytic degradation by RGO/NT on Batik wastewater under visible light showed higher effectivity than under UV light.

Novel cyclic undecapeptides immobilized on reduced graphene oxide surface for enhanced antibacterial properties

Novel cyclic undecapeptides immobilized on reduced graphene oxide surface for enhanced antibacterial properties