Reduced graphene oxide: an introduction

Researchers from Taiwan's National Cheng Kung University and Chung Yuan Christian University have developed an interface-engineering strategy to overcome key efficiency bottlenecks in mesoporous perovskite solar cells by introducing APTS-functionalized reduced graphene oxide (APTS-rGO) into the electron transport structure.

In this work, reduced graphene oxide (rGO) was chemically modified using 3-aminopropyltriethoxysilane (APTS), a silane coupling agent with both amine and silane functional groups. This dual functionality enables strong bonding with oxide surfaces such as TiO₂ while simultaneously improving compatibility with the perovskite layer.

Researchers from Hebei University of Technology, Zhejiang Sci-Tech University, Nanjing University of Information Science and Technology and The Pennsylvania State University recently reported on a high-performance flexible pressure sensor based on an anisotropic reduced graphene oxide aerogel (rGOA), addressing the long-standing challenge of simultaneously achieving ultra-high sensitivity and a wide detection range in wearable and robotic sensing systems.

The device architecture integrates the rGOA sensing layer between a polyimide (PI) film with interdigital electrodes and a thin polydimethylsiloxane (PDMS) encapsulation layer. The aerogel itself is fabricated via a freeze-casting process that induces a highly ordered anisotropic structure. By controlling the freezing direction of the graphene oxide precursor, the researchers form a lamellar, porous 3D network that enables controlled deformation under pressure and efficient modulation of electrical pathways.

Researchers at India's Cochin University of Science and Technology have developed a bifunctional polyaniline/reduced graphene oxide (PRGO) interlayer integrated into a lithium-sulfur (Li-S) battery separator, demonstrating a practical route to mitigating polysulfide shuttling while improving electrochemical performance.

Li-S systems offer a theoretical specific capacity of 1675 mAh g⁻¹ and energy density approaching 2600 Wh kg⁻¹, but their commercialization has been hindered by sulfur’s extremely low conductivity (~5×10⁻³⁰ S cm⁻¹) and the dissolution and migration of lithium polysulfides (LiPSs). These soluble intermediates form during discharge - initially at 2.1–2.4V (long-chain polysulfides, ~25% of capacity, 418 mAh g⁻¹) and then at 1.6–2.1V (short-chain species, ~75%, 1257 mAh g⁻¹) - and readily diffuse toward the lithium anode, causing active material loss and rapid capacity fading.

Researchers at Oregon State University (OSU), National Taipei University of Technology and Ming Chi University of Technology have developed a nanoscale electrochemical sensor that can measure theobromine in beverages with high sensitivity and accuracy. The central concept is engineered interfacial chemistry: the material creates localized alkaline microdomains directly at the electrode surface, enabling efficient electrochemical oxidation of theobromine while the bulk solution remains at neutral pH.

The sensing layer is a ternary nanocomposite combining strontium oxide (SrO), functionalized carbon black (f‑CB) and reduced graphene oxide (r‑GO). SrO forms nanoscale alkaline domains that facilitate interfacial proton abstraction from theobromine, effectively activating this weakly electroactive molecule at neutral pH. Reduced graphene oxide provides a highly conductive, high-surface-area network and engages in π–π interactions with the heterocyclic xanthine core of theobromine, enhancing adsorption at the electrode. Functionalized carbon black strengthens cross‑nanointerface electron transfer and remains a dominant pathway for charge transport, improving overall electrochemical performance.

Researchers from Hangzhou Normal University, Zhejiang Province Environmental Engineering Co., Hangzhou Hengjun Environmental Engineering Co., Zhejiang Carbon Reduction Technology Co., Princess Nourah bint Abdulrahman University, Kimyo International University in Tashkent, Urgench State University and Islamic University of Madinah have developed a graphene-enhanced electroadsorbent that tackles persistent PFAS pollutants in water.

PFAS are fluorinated pollutants that resist breakdown, accumulate in supplies, and challenge conventional treatments like carbon filters or membranes, which generate waste.

Researchers from the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and Institute of Microelectronics of Barcelona (CSIC) recently presented graphene-based brain interfaces that are more robust and durable, thanks to a hybrid coating of organic and inorganic materials. This represents an important step toward developing a new generation of neural interfaces designed for long-term clinical use.

Graphene-based neural interfaces, which are thin, flexible devices that can record and stimulate brain activity with remarkable precision,  are already being tested in clinical procedures, including brain tumor surgeries. They are also being explored as potential tools for treating neurological disorders, such as Parkinson's disease.

Researchers from India and the U.S have examined the application of nitrogen-doped reduced graphene oxide (NRGO) sponge electrodes within bioelectrochemical systems (BES) for simultaneous water and soil remediation. This approach addresses critical limitations in conventional disinfection and decontamination techniques, which often involve high energy consumption, extensive chemical usage, and the formation of secondary pollutants such as perchlorates and chlorinated byproducts.

The study highlights NRGO electrodes as an efficient and environmentally compatible platform for integrated detoxification. In aqueous systems, NRGO anodes achieved complete inactivation of Escherichia coli (5-log reduction) at a current density of 115 A m⁻², primarily through electrosorption and electroporation mechanisms, without producing chlorine-based residuals. In soil environments, embedded NRGO electrodes facilitated enhanced microbial extracellular electron transfer and pollutant adsorption, resulting in a 75% decrease in polycyclic aromatic hydrocarbons (PAHs) and a 32% immobilization of lead (Pb) within 20 days.

Monash University researchers have developed a new form of multiscale graphene that overcomes long-standing limitations in supercapacitor technology. While supercapacitors offer rapid power delivery, their use has been restricted by low volumetric energy density and inefficient ion transport in conventional carbon materials. The Monash team addressed this by applying a rapid thermal annealing step to graphite oxide, producing highly curved, turbostratic graphene crystallites interwoven with disordered domains. This architecture creates efficient ion pathways and enables partial charge transfer within the graphene interlayers, significantly boosting accessible surface area.

The differences between lamellar, disordered and multiscale graphene with morphological characterization of M-rGO. Image from: Nature Communications

The resulting material, termed multiscale reduced graphene oxide (M-rGO), delivers a Brunauer–Emmett–Teller capacitance of 85 μF/cm² and enables supercapacitor electrodes with both high energy and power densities. When assembled into symmetric pouch-cell devices, M-rGO supercapacitors achieved stack-level volumetric energy densities of up to 99.5 Wh/L in ionic liquid electrolytes and demonstrated rapid charge-discharge performance with power densities as high as 69.2 kW/L, along with excellent long-term stability.

Researchers from Brazil's Federal University of Paraíba – UFPB and Portugals' University of Aveiro and LASI (Intelligent Systems Associate Laboratory) have presented a simple and cost-effective approach for the one-step synthesis of MnCo₂O₄-reduced graphene oxide (MCO-rGO) for use as an anode material in the oxygen evolution reaction (OER). 

Both MCO and rGO were formed on a porous Ni foam through a wet chemical process, via oxidation of the spinel phase and the simultaneous thermal reduction of graphene oxide (GO) in an air atmosphere at 300 °C. The (electro)catalytic properties of the MCO-based electrodes were studied in an alkaline medium (1 M KOH) to evaluate the impact of rGO on various OER activity parameters, in controlled amounts of 10 wt% and 20 wt% GO. 

Electromagnetic wave absorption materials inevitably encounter corrosive conditions during service, making corrosion-resistant design essential for their practical deployment. 

Researchers from China's Northwestern Polytechnical University have developed a magnetic graphene composite aerogel (reduced graphene oxide (rGO)/ porous hollow Ni/C microspheres (PHNiC)). The new aerogel reportedly demonstrates excellent impedance matching and electromagnetic attenuation, achieving a minimum reflection loss of −51.3 dB at a thickness of 2.5 mm and a broad effective absorption bandwidth of 6.64 GHz.