Reduced Graphene Oxide Layers Research Articles

High sensitivity in quantitative analysis of mixed-size polystyrene micro/nanoplastics in one step

As emerging environmental pollutants, microplastics (MPs) and nanoplastics (NPs) pose a serious threat to human health. Owing to the lack of feasible and reliable analytical methods, the separation and identification of MPs and NPs of different sizes remains a challenge. In this study, a hyphenated method involving filtration and surface-enhanced Raman spectroscopy (SERS) for the separation and identification of MPs and NPs is reported. This method not only avoids the loss of MPs and NPs during the transfer process but also provides an excellent SERS substrate. The SERS substrate was fabricated by electrochemically depositing silver particles onto the reduced graphene oxide layer coated on stainless steel mesh. Results show that polystyrene (PS) MPs and NPs are efficiently separated on the SERS substrate via vacuum filtration, resulting in high retention rates (74.26 % ± 1.58 % for 100 nm, 81.06 % ± 1.49 % for 500 nm, and 97.73 % ±0.11 % for 5 μm) and low limit of detection (LOD). The LOD values of 100 nm, 500 nm, and 5 μm PS are 8.89 × 10−5, 3.39 × 10−5, and 1.57 × 10−4 μg/mL, respectively. More importantly, a linear relationship for uniform quantification of 100 nm, 500 nm, 3 μm and 5 μm PS was established, and the relationship is Y = 225.61 lgX + 1076.36 with R2 = 0.980. The method was validated for the quantitative analysis of a mixture of 100 nm, 500 nm PS NPs, 3 μm and 5 μm PS MPs in a ratio of 1:1:1:1, which successfully approaches the evaluation of evaluated PS NPs in the range of 10−4–10 μg/mL with an LOD value of approximately 7.82 × 10−5 μg/mL. Moreover, this method successfully detected (3.87 ± 0.06) × 10−5 μg MPs and NPs per gram of oyster tissue.

Facile preparation and broadband microwave absorption of multilayered materials based on thin films of reduced graphene oxide

Microwave absorption (MA) materials have received extensive attention for their wide applications in both civil and military areas. However, many MA materials have a large thickness, high filling ratio, and narrow effective microwave absorption bandwidth (Reflection Loss, RL ≤ −10 dB) (EAB), and are prepared by complex processes. In this work, a reduced graphene oxide (RGO) film is prepared for the first time by an approach involving floating-dipping and chemical reduction. Compared with previous micrometers-thick RGO films, the present 200 nm-thick dense RGO film is critical for improving not only the impedance matching but also the capability of the material to attenuate incident microwaves. Based on such a thin RGO film, a multilayered material with a jaaumann structure is constructed with individual RGO layers alternating between low dielectric polyethylene terephthalate (PET) sheets. With the superb impedance matching, multilayer attenuation, and multi-cavity resonance, the present multilayered material can achieve a wide EAB of 13.75 GHz with a minimum reflection loss of −47.69 dB using only 3 layers of RGO films. This study provides a new and simple strategy for the development of layered materials with a thin thickness, low filling ratio, and strong absorption with a wide EAB.

Investigating the thermally induced p-n transition in reduced graphene oxide layers exposed to hydrogen sulfide

To investigate the origin of the p-n transition observed in graphene-based materials for chemical sensors, we developed sensing layers made of chemically reduced graphene oxide (rGO), prepared from graphene oxide (GO) using citrate as a reducing agent. We focused mainly on the thermally induced p-n transition when the sensing layers are exposed to H2S at a specific temperature. The rGO sensing layers are prepared through drop casting on interdigitated electrodes. Scanning electron and transmission electron microscopes allow the characterization of the rGO structure, while FTIR, X-ray photoelectron spectroscopy, and electrical characterization have revealed the reduction efficiency. The p-n transition occurs between 80 °C and 90 °C, whatever the resistance range and the exposition history to H2S. The temperature-dependent transition, which starts around 80–90 °C, is reversible if the temperature is kept below 80 °C, i.e., the rGO remains p-type material. When experiments are performed at a temperature above 90 °C, the transition from p-type to n-type takes place, and the n-type persists, showing an irreversible transition. The transition starts gradually at 80 °C during lower concentration exposure and ends at high concentration. Finally, the results show that temperature and H2S contribute to the inversion of the initial charge carriers.

Electrochemical coverage of reduced graphene oxide layers on sulfur supported by biochar for enhancing performance of Li-S battery

To improve the electrochemical performance of Li-S batteries, a cathodic material (rGO150/S/CF-75) was fabricated for Li-S batteries by adopting a melt-flow method to load sulfur on biomass-derived carbon fibers, then the reduced graphene oxide was electrochemically covered on the outside surface of the sulfur. The coverage of reduced graphite oxide layers endows the performance of S/CF-75 multiple improvements. The specific capacity of rGO150/S/CF-75 cathode delivers a specific capacity of 1451.4 mAh g−1 at 0.1 A g−1. The specific capacity of rGO150/S/CF-75 cathode can still maintain 537.3 mAh g−1 after 1000 cycles at 5 A g−1 (109 % capacity retention). The excellent performance of rGO150/S/CF-75 cathode is benefit from not only the conductive paths of reduced graphene oxide layers and protective function of reduced graphene oxide layers inhibiting that the soluble sulfur diffuse into bulk electrolyte, but also the redistribution of sulfur on conductive carbon components during the cycling process.

Ultrafast Bi-Directional Bending Moisture-Responsive Soft Actuators through Superfine Silk Rod Modified Bio-Mimicking Hierarchical Layered Structure.

Development of stimulus-responsive materials is crucial for novel soft actuators. Among these actuators, the moisture-responsive actuators are known for their accessibility, eco-friendliness, and robust regenerative attributes. A major challenge of moisture-responsive soft actuators (MRSAs) is achieving significant bending curvature within short response times. Many plants naturally perform large deformation through a layered hierarchical structure in response to moisture stimuli. Drawing inspiration from the bionic structure of Delosperma nakurense (D. nakurense) seed capsule, here the fabrication of an ultrafast bi-directional bending MRSAs is reported. Combining a superfine silk fibroin rod (SFR) modified graphene oxide (GO) moisture-responsive layer with a moisture-inert layer ofreduced graphene oxide (RGO), this actuator demonstrated large bi-directional bending deformation (-4.06±0.09 to 10.44±0.00cm-1) and ultrafast bending rates (7.06cm-1s-1). The high deformation rate is achieved by incorporating the SFR into the moisture-responsive layers, facilitating rapid water transmission within the interlayer structure. The complex yet predictable deformations of this actuator are demonstrated that can be utilized in smart switch, robotic arms, and walking device. The proposed SFR modification method is simple and versatile, enhancing the functionality of hierarchical layered actuators. It holds the potential to advance intelligent soft robots for application in confined environments.

Tin oxide quantum dots embedded between graphene sheets to improve non-aqueous aluminum ion battery performance

A composite of tin oxide quantum dots (SnO2QDs) and reduced graphene oxide (RGO), was synthesized using the rapid microwave synthesis method and used as cathode material in the non-aqueous aluminum ion battery. In addition, graphene oxide (GO) and RGO were also prepared separately, and the properties of the resulting cathode materials were compared using XRD, FESEM, Raman, and HRTEM. RGO/SnO2QDs, GO, and RGO were mixed separately with a binder at a ratio of 90:10 and the resulting slurries were coated on a graphite sheet. The electrochemical performance of the graphite sheet, GO, RGO, and RGO/SnO2QDs cathodes was investigated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge-discharge tests in an electrochemical cell containing an ionic liquid (AlCl3/Et3NHCl) as an electrolyte and aluminum as an anode. The battery with RGO/SnO2QDs cathode exhibited an excellent specific discharge capacity of 231 mAh g−1 at 2 A g−1 after 300 cycles with a Coulomb efficiency of 98.3 %. Furthermore, after 25,000 charge and discharge cycles at 2.5 A g−1, the Al||RGO/SnO2QDs battery demonstrated a specific discharge capacity of 163 mAh g−1, with a Coulombic efficiency of 89 %. Additionally, the superior battery also displayed impressive speed performance, achieving a specific discharge capacity of 124.6 mAh g−1 at 4 A g−1, with a Coulombic efficiency of 98.6 %. A comparison of the results of four prepared batteries showed that the synergistic effect of SnO2QDs and RGO layers makes for a suitable cathode material for rechargeable aluminum-ion batteries.

Boosting the oxygen bifunctional activity on cobalt nanocrystals/RGO with extended durability

Nanoengineering effective bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a major challenge in improving the performance of electrochemical energy conversion devices. In this study, we present a simple synthesis route for producing Co-Nx crystals that are effectively arranged on reduced graphene oxide layers (Co–N/RGO) through mechanochemical treatment. The Co–N/RGO catalyst performs well as a bifunctional oxygen electrocatalyst. Specifically, the Co–N/RGO-700 has an earlier ORR onset (0.91 V) and a half-wave potential (0.79 V) with a higher kinetic current density of 6.6 mA cm−2 than Pt/C, as well as a lower overpotential (430 mV) and Tafel slope (115 mV dec−1) for the OER. These results demonstrate outstanding performance compared to reported Co-based catalysts. Theoretical modeling and experimental results explore the Co–N/RGO active sites, as well as the vital role of electronic structure, abundant N content, and surface defects, confirming it as a potential electrode material for energy conversion applications.

A dual-carbon structured molybdenum selenide composites controlled via interface engineering and chemical bonding to attain high initial coulombic efficiency and rate capability of potassium-ion batteries

Molybdenum selenide (MoSe2) is considered representative anode material for Potassium-ion batteries (PIBs) by reason of its adjustable forbidden bandwidth and large interlayer spacing allowing the intercalation/deintercalation of large-sized K+. However, its inferior electronic conductivity, substantial volume variation, and aggregation make it difficult to achieve satisfactory cycling performance and rate capability. Herein, we reported a novel composite with MoSe2 nanosheets grown vertically on the surface of N-doped hollow porous carbon bowls and wrapped by ultrathin/wrinkled reduced graphene oxide layers (G-MoSe2/NHPCB) as the anode material for PIBs. The strong chemical bonds between MoSe2 and carbon materials (including C-Mo, C-O-Mo, and C-N-Mo bonds) were profitable for the charge-transfer kinetics and structural durability. The NHPCB substrate, with a large specific surface area, could significantly prohibit the aggregation of MoSe2 nanosheets and shorten the transmission path for electrons and ions. Meanwhile, the ultrathin/wrinkled graphene layers could effectively strengthen the composite structure stability and reinforce the overall conductivity. Benefitting from the distinctive structure, when evaluated as a K-ion half-cell anode, the G-MoSe2/NHPCB electrode exhibited a high discharge capacity of 601.59 mA h g−1 and initial coulombic efficiency (ICE) of 83.4% at 0.1 A/g, exceptional rate capability (261.3 mA h g−1 at 5.0 A/g) and long-term cycling stability (304.3 mA h g−1 at 1.0 A/g after 500 cycles and 214.9 mA h g−1 at 2.0 A/g after 1000 cycles). The electrochemical reaction mechanism and kinetic analysis were investigated using in-situ and ex-situ methods and first-principles calculation. This work demonstrates the advantages of G-MoSe2/NHPCB as KIBs anode materials and provides innovative thinking for the rational design of high-performance transition metal selenides with unique structures.

Enhanced Photocatalytic CO2 Reduction to CH4 Using Novel Ternary Photocatalyst RGO/Au-TNTAs

Photocatalytic CO2 reduction into hydrocarbon fuels is one of the most efficient processes since it serves as a renewable energy source while also lowering atmospheric CO2 levels. The development of appropriate materials and technology to attain greater yield in CO2 photoreduction is one of the key issues facing the 21st century. This study successfully fabricated novel ternary reduced graphene oxide (RGO)/Au-TiO2 nanotube arrays (TNTAs) photocatalysts to promote CO2 photoreduction to CH4. Visible light-responsive RGO/Au-TNTAs composite was synthesized by facile electrochemical deposition of Au nanoparticles (NPs) and immersion of RGO nanosheets onto TNTAs. The synthesized composite has been thoroughly investigated by FESEM, HR-TEM, XRD, XPS, FT-IR, UV-Vis DRS, and PL analyzer to explain structural and functional performance. Under the source of visible light, the maximum yield of CH4 was attained at 35.13 ppm/cm2 for the RGO/Au-TNTAs composite photocatalyst after 4 h, which was considerably higher by a wide margin than that of pure TNTAs, Au-TNTAs and RGO-TNTAs. The CO2 photoreduction of the RGO/Au-TNTAs composite has been improved due to the combined effects of Au NPs and RGO. Due to its surface plasmonic resonance (SPR) mechanism, Au NPs play a crucial role in the absorption of visible light. Additionally, the middle RGO layers serve as effective electron transporters, facilitating better separation of electron-hole pairs. The newly constructed composite would be a promising photocatalyst for future photocatalytic applications in other fields.

Cu3(hexaamino triphenylhexane)2/reduced graphene oxide composites with boosting electron-transfer properties for acetaminophen electrocatalytic degradation

Electron-transfer properties, as great contributors for electrocatalytic oxidation on the anode, are crucial to pollution degradation. The strong relationship between electron-transfer properties and active species (such as radicals) generation of anode catalysts suggests a new strategy for pollution-degradation efficiency improvement. In this study, a novel composite of Cu3(hexaamino triphenylhexane)2 [Cu3(HITP)2] and reduced graphene oxide (RGO) was synthesized to construct electron-transfer pathways between the two layers. Benefiting from the connection formed through RGO-O-N-Cu, the electron transfer from RGO to Cu3(HITP)2 was accelerated. The resettled charge distribution led the C atoms in the RGO layer, and the Cu and C atoms in Cu3(HITP)2 layer acted as the main surface active sites. O2•–, 1O2, and reactive chlorine were then triggered to boost the degradation of acetaminophen. The source of O2•– and 1O2 was more likely from surface oxygen groups rather than dissolved O2. Overall, this research provided a perspective proof of conductive Cu3(HITP)2/RGO composite construction with 2D/2D structure for electrocatalytic-oxidation improvement.

Unlocking the Stability of Reduced Graphene Oxide Nanosheets in Biological Media via Use of Sodium Ascorbate

AbstractGraphene oxide and reduced graphene oxide (RGO) are carbon bidimensional nanomaterials largely exploited in biomedicine. Their unique interactions with eukaryotic and prokaryotic cells are used to obtain precise intracellular delivery, to create device coatings, and to design theranostic materials for both therapeutic and imaging applications, mainly in the cancer research field. It is known, however, that the hydrophobic behavior of RGO limits its stability in biological media. Here, the employment of sodium ascorbate (NaA) as a reducing agent for the preparation of RGO to provide a nanomaterial with remarkable suitability for applications in cell culture media is proposed. It is demonstrated via a combined experimental and theoretical approach that NaA is able to yield a peculiar RGO derivative, exerting a twofold effect, that is, C sp2 network restoration upon epoxide reduction and RGO edge functionalization via H‐bonding, lending RGO a so far unexampled dispersibility in aqueous‐based media. The kinetic stability of the bidimensional layers of RGO obtained from NaA is demonstrated together with its superior biocompatibility for drug delivery, unlocking outstanding potentialities for biological applications.

Modifying platinum microelectrodes with electrochemically reduced graphene oxide for application in electrochemical ascorbic acid sensor

Graphene oxide drop-casted on a platinum microelectrode was successfully changed to reduced graphene oxide by using a cyclic voltammetry method. The presence of an electrochemically reduced graphene oxide layer on the platinum electrode was proved by using scanning electron microscopy images, Raman and Fourier-transform infrared spectroscopy spectra. Cyclic voltammetry and linear sweep voltammetry results indicated that the platinum microelectrode modified with electrochemically reduced graphene oxide can be used as an electrochemical sensor for detection of ascorbic acid in aqueous solutions. In a cyclic voltammetry scan and a linear sweep voltammetry curve corresponding to the presence of ascorbic acid, a peak related to the direct oxidation of ascorbic acid appears. The electrochemical sensor based on the electrochemically reduced graphene oxide material works effectively with a detection limit of 0.04 mM, a detection linear range from 0.04 mM to 1.0 mM, a good repeatability, and especially, a rapid detection time thanks to a direct ascorbic acid detection based on the oxidation of ascorbic acid.

2D hydroxylated MXene (OH-MXene)/RGO composites modification toward superior electrocatalytic degradation of paracetamol

The MXene precursor was adjusted with a combination of –OH grafting and reduced graphene oxide (RGO) via alkalization and hydrothermal method to improve the electrocatalytic performance. The as-prepared hydroxylated MXene (OH-MXene)/RGO composites possess maximum 100 % paracetamol (APAP) degradation efficiency under an applied current of 15 mA, temperature of 25 °C, and electrolyte of 1 g/L NaCl. All characterization and experiment results showed that the grafting of –OH groups into MXene could access the active site of Ti-OH, strengthen the linking of OH-MXene and RGO layers (as C-Ti-Ox), accelerate the free electrons transfer from OH-MXene to RGO; thus, enhancing the catalytic activity of OH-MXene/RGO composites. Then, •OH, 1O2, O2•−, and active chlorine were determined as secondary active species in the solution, which dominated the APAP degradation. Three degradation pathways of APAP were further proven by gas chromatography-mass spectrum (GC–MS) with cleavage of N-branched chain and benzene rings. In addition, the superior and stable performance of OH-MG-15h under various operation conditions confirmed the application perspective of self-prepared material. The research not only provides feasible methods for MXene adjustment and electrocatalytic activity improvement but also proves its possibility for environmental application.

Reduced graphene oxide-functionalized zinc oxide nanorods as promising nanocomposites for white light emitting diodes and reliable UV photodetection devices

We present a breakthrough in the development of novel nanocomposites based on reduced graphene oxide (RGO)-functionalized zinc oxide (ZnO) nanorods that hold exceptional promise for their use in white light emitting diodes (LEDs) and reliable UV photodetection. The nanorods had a pristine hexagonal wurtzite structure, as confirmed by XRD analysis. SEM images revealed sandwich-like nanocomposites with ZnO nanorods coated in reduced graphene oxide and embedded between two layers of RGO. The study also confirmed the hybridization and interactions between the layers using Raman measurements. The resulting nanocomposites displayed a lower band gap energy than ZnO and exhibited unique photoluminescence spectra with a white PL light. The photodetector based on RGO/ZnO/RGO sandwich structures demonstrated exceptional photoresponse, with higher photocurrent under UV illumination, making it highly promising for a wide range of optoelectronic applications. Overall, this study offers a novel and powerful approach to create nanocomposite structures with enhanced optical characteristics.

Three-dimensional multimodal porous graphene-carbonized wood for highly efficient solar steam generation

Recently, solar steam generation systems have become a promising solar energy technology that can alleviate the energy crisis and reduce water pollution. However, because of weak solar radiation energy, rapid heat loss, and negative environmental impacts, there are still numerous challenges that must be overcome before solar steam generation systems can be used for practical energy utilization. Inspired by natural tree transpiration, this paper reports a 3D carbonized wood (hydrophilic)-based photothermal system coated with 2D porous reduced graphene oxide (hydrophobic) to promote solar steam generation. Wood with vertically aligned microchannels and high hydrophilicity is used to efficiently pump water, which is then spread to a 2D porous reduced graphene oxide layer with a sufficient evaporation surface. The unique 3D micro-sized water reservoirs formed between the wood and reduced graphene oxide maximize the thermal energy use of the graphene layer by preventing heat loss from its transference to the water and reducing light reflection. The evaporation rate and solar energy conversion efficiency were 1.492 kg⋅m−2⋅h−1 and 94.7% under 1 sun illumination, respectively. Moreover, our solar steam evaporator maintained its original evaporation rate after 20 h. This work provides new insights into the structural design for highly efficient solar steam generation devices.

Speech Recognition Using Intelligent Piezoresistive Sensor Based on Polystyrene Sphere Microstructures

Rapid advances in wearable sensing technology have demonstrated unprecedented opportunities for artificial intelligence. In comparison with the traditional hand‐held electrolarynx, a wearable and intelligent artificial throat with sound‐sensing ability is a more comfortable and versatile method to assist disabled people with communication. Herein, a piezoresistive sensor with a novel configuration is demonstrated, which consists of polystyrene (PS) spheres as microstructures sandwiched between silver nanowires and reduced graphene oxide layers. In fact, changes in the device's conducting patterns are obtained by spay‐coating the various weight ratios and sizes of the PS microspheres, which is a fast and convenient way to establish microstructures for improving sensitivity. The wearable artificial throat device also exhibits high sensitivity, fast response time, and ultralow intensity level detection. Moreover, the device's excellent mechanical–electrical performance allows it to detect subtle throat vibrations that can be converted into controllable sounds. In this case, an intelligent artificial throat is achieved by combining a deep learning algorithm with a highly flexible piezoresistive sensor to successfully recognize five different words (help, sick, patient, doctor, and COVID) with an accuracy exceeding 96%. Herein, new opportunities in voice control as well as other human‐machine interface applications are opened.

A comparison of the crystal structure and optical properties of reduced graphene oxide and aminated graphene nanosheets for optoelectronic device applications

Optical properties of graphene transform in presence of amine or amide groups. So, the comparison of the linear and nonlinear optical (NLO) properties of reduced graphene oxide (RGO) nanosheets and aminated graphene (AMG) nanosheets will significantly accelerate the development of a flexible optoelectronic device based on this material in the future. In this paper, the structural and optical properties of RGO and AMG are investigated by TEM, XRD, Raman, and UV-Vis analysis. TEM images show the formation of the very thin layer of RGO and AMG nanosheets. The peak of XRD spectra (26.6◦) for both indicate the good quality of crystallization of RGO and AMG. Raman spectra result in ID/IG of about 0.9 and 1.1 for RGO and AMG, respectively. Also, different functional groups for RGO and AMG nanosheets are shown in FTIR spectra. Then, Kramers-Kronig (KK) method was employed to determine the dielectric function, ε̃(λ), extinction coefficient, k(λ) and refractive index, n(λ). Third-order optical nonlinearities of nanosheets dispersed in DMF are investigated with the Z-scan method. The nanosheets achieve an appropriate figure of merit (FOM) due to their high nonlinear refractive (NLR) index, n2 (10−8cm2/W) and low nonlinear absorption (NLA) coefficient, β (10−4cm/W).

Piezoresistive Pressure Sensor Based on a Conductive 3D Sponge Network for Motion Sensing and Human-Machine Interface.

Flexible sensors have attracted increasing attention owing to their important applications in human activity monitoring, medical diagnosis, and human-machine interaction. However, the rational design of low-cost sensors with desirable properties (e.g., high sensitivity and excellent stability) and extended applications is still a great challenge. Herein, a simple and cost-effective strategy is reported by immersing polyurethane (PU) sponge in graphene oxide solution followed by in situ chemical reduction to construct a reduced graphene oxide (RGO)-wrapped PU sponge sensor. Ascribed to the excellent compressive resilience of PU sponge and an electrically conductive RGO layer, the constructed flexible sensor exhibits satisfactory sensing performance with high sensitivity (17.65 kPa-1) in a low-load range (0-3.2 kPa), a wide compression strain range (0-80%), and reliable stability (8000 cycles). In addition, these sensors can be successfully applied to monitor human movements and identify the weight of objects. Through the use of a sensor array integrated with a signal acquisition circuit, the reasonably designed sensors can realize tactile feedback via mapping real-time spatial distribution of pressure in complicated tasks and show potential applications in flexible electronic pianos, electronic skin, and remote real-time control of home electronics.

Reduced graphene oxide layers full of bubbles for electromagnetic interference shielding

The rGO bubbles are prepared by a template-free method and show a high EMI SE, ascribed to the multiple reflections and absorption of their conductive network.

Effects of TiO2-Modified RGO Composites on the Mechanical and Durability Properties of Ordinary Portland Cement Mortars

Various applications of graphene-based materials in construction are an alternative to improve the properties of ordinary Portland cement (OPC)-based binders. This paper used a titanium dioxide in situ intercalation method to enhance the dispersibility of reduced graphene oxide (RGO) and then explored the effects of the incorporation of the obtained TiO2–RGO composite and RGO on the mechanical and durability-related properties of the OPC-based binders. Experimental results showed that TiO2 was successfully intercalated into the RGO layers and could improve the dispersion of RGO in water or synthesized OPC pore solution significantly, probably due to the greater spacing between each RGO layer. Besides, a proper amount of TiO2-modified RGO composite (0.03 wt % in this study) could elevate the mechanical strengths of OPC mortars, evidenced by a large increment of 24.78% and up to 34.94% in the compressive strength and flexural strength, respectively. The TiO2–RGO composite led to higher flexural-to-compressive strength ratios with the given dosages (0.01–0.05 wt %), implying a higher fractural toughness. Moreover, the resistance of the enhanced OPC-based mortars toward chloride attacks and freeze–thaw cycles was significantly improved. Based on the microstructural analyses including scanning electron microscopy and X-ray diffraction results, it is found that the modified RGO could to some extent promote the hydration of OPC and densify the overall microstructure of bulk specimens, leading to enhanced mechanical and durability properties. Compared to normal RGO, the TiO2–RGO composite was more effective in enhancing the properties of OPC mortars, due in large part to its better dispersion state.