Platinum (Pt) remains the benchmark catalyst for the hydrogen evolution reaction (HER), yet its performance in alkaline media is limited by sluggish water dissociation kinetics. Herein, we report a facile polyol synthesis of Pt nanoparticles supported on delaminated Mo2CTz MXene labeled d-Mo2CTz and comparison is made with a reference Pt/carbon (C) catalyst at similar metal loadings. While structural analyses reveal comparable particle sizes, enabling isolation of support effects, XPS and electrochemical measurements evidence metal support interaction in Pt/d-Mo2CTz, leading to modified hydrogen adsorption behavior. As a result, Pt/d-Mo2CTz exhibits enhanced HER activity in alkaline media, requiring an overpotential as low as 48 mV at − 10 mA cm− 2 to be compared to 70 mV for Pt/C. This enhanced activity is attributed to two different phenomena: Pt ensures hydrogen recombination and the MXene support promotes water adsorption, activation, and hydroxide removal thanks to its hydrophilic/oxophilic properties. These findings highlight the active role of MXene supports in tuning Pt electrocatalysis properties and provide new design strategies for efficient alkaline electrolyzers.
Graphene-based materials, including graphene, graphene oxide (GO), reduced graphene oxide (rGO), graphane, graphone, fluorographene, graphyne, and graphdiyne, have emerged as a versatile family of two-dimensional carbon nanomaterials with exceptional potential for pesticide detection, environmental remediation, and sustainable agriculture. This review provides a comprehensive and critical overview of recent advances in the synthesis, characterization, physicochemical properties, and pesticide detection and removal applications of graphene derivatives. Particular emphasis is placed on the relationship between synthesis strategies, structural engineering, defect modulation, surface functionalization, electronic properties, and adsorption behavior, which collectively determine the performance of graphene-derived materials in pesticide sensing, adsorption, and photocatalytic degradation. The review further discusses the distinctive properties of graphene derivatives, including their ultrahigh specific surface area, tunable electronic conductivity, excellent mechanical strength, rich surface chemistry, and superior adsorption capacity, which enable enhanced interaction with pesticide molecules and improved analytical sensitivity and catalytic efficiency. In addition, the review highlights the major challenges associated with large-scale synthesis, cost-effective production, structural stability, material reproducibility, selectivity in complex environmental matrices, environmental fate, toxicity, and industrial commercialization. This review bridges the gap between fundamental material design and real-world agricultural and environmental applications, providing valuable insights for the development of next-generation graphene-based technologies for efficient pesticide monitoring, removal, and sustainable environmental management.
Graphene-based nanoelectronic biosensors have emerged as transformative platforms for early disease detection due to their exceptional electrical conductivity, high carrier mobility, and large surface-to-volume ratio enabling ultra-sensitive biomolecular interactions. This review critically examines the integration of graphene and its derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), into advanced biosensing systems, emphasizing structure–property relationships governing analytical performance. Key device configurations, including field-effect transistors (FETs), electrochemical sensors, and optical platforms, are analyzed, demonstrating detection limits ranging from femtomolar to attomolar levels depending on sensor architecture, target biomarker, and sensing conditions, with rapid response times under optimized conditions. Surface functionalization strategies such as covalent modification and π–π stacking are highlighted for improving selectivity toward proteins, nucleic acids, and small-molecule biomarkers while reducing nonspecific interactions. Applications across oncology, infectious diseases, and neurodegenerative disorders illustrate multiplexed detection and clinically relevant sensitivity. Compared to conventional systems, graphene-enabled biosensors exhibit superior signal-to-noise ratios and real-time monitoring capabilities in complex biological environments. Challenges including reproducibility, long-term stability, and scalable fabrication are discussed, along with emerging solutions involving hybrid nanomaterials and microfluidic integration. The review concludes with a translational perspective on point-of-care and wearable biosensing technologies, highlighting graphene nanoelectronics as a key driver of precision diagnostics.
This work reports a sustainable route for synthesizing a silver nanoparticle/reduced graphene oxide nanocomposite supported on activated carbon (AgNPs/rGO/AC810), using aqueous extract of guarana seed skins as a natural reducing and stabilizing agent. The extract promotes the reduction of Ag⁺ to silver nanoparticles (AgNPs) and graphene oxide (GO) to reduced graphene oxide (rGO), followed by deposition onto commercial activated carbon (AC810). UV–vis spectroscopy revealed the Ag surface plasmon resonance band and provided evidence of GO reduction to rGO, with the GO band at λmax ≈ 235 nm disappearing and a broad rGO band appearing at λmax ≈ 398 nm. XRD analysis revealed the face-centered cubic structure of metallic Ag with an average crystallite size of 11.39 nm. HR-TEM images showed uniformly dispersed spherical AgNPs anchored on rGO sheets and within AC810 pores, with average sizes of 8 nm in AgNPs/rGO and 13 nm in AgNPs/rGO/AC810. Raman and ATR-FTIR analyses supported the partial restoration of sp² domains, with ID/IG values of 1.20 for GO and 1.10 for AgNPs/rGO, and characteristic carbon functionalities. BET/BJH analysis revealed a high surface area of approximately 600 m² g⁻¹ and a predominantly mesoporous structure, favorable for active-site accessibility and mass transport. DLS/zeta potential results indicated colloidal stability under alkaline conditions, with hydrodynamic diameter around 240 nm and zeta potential near − 30 to − 35 mV. Electrochemical characterization showed a significant increase in ECSA from 0.003 cm² for GCE to 0.177 cm² for AgNPs/rGO/AC810/GCE, corresponding to an approximately 59-fold enhancement and a roughness factor increase from 0.03 to 1.77, indicating a high density of accessible active sites. These results indicate that AgNPs/rGO/AC810 is a low-cost and versatile nanocomposite platform for future CO₂RR studies.
Recent advances in forensic science highlight the emerging role of nanotechnology and sensor-based systems in enhancing diagnostic accuracy and sensitivity. These two techniques, though complementary, offer distinct mechanisms of action that innovate the forensic investigations. Advances in nanomaterial-based assays for biological fluid analysis enable rapid, reliable molecular-level detection, thereby improving the accuracy of forensic diagnostics. Carbon-based nanomaterials, including graphene, carbon dots, and carbon nanotubes, are increasingly exploited for their tunable optical, electrochemical, and surface properties, which enable ultrasensitive detection of illicit drugs, explosive residues, toxic metals, and trace biomolecules, while also enhancing latent fingerprint visualisation. Parallel advances in sensor engineering have enabled highly selective optical, electrochemical, and biosensing systems capable of detecting minute forensic evidence directly at crime scenes. Carbon nanomaterial-based sensing platforms have significantly advanced forensic science by addressing the limitations of conventional analytical techniques, particularly in terms of sensitivity, portability, and response time. The incorporation of these nanomaterials with miniaturised, digitally integrated sensing devices has shifted forensic analysis toward real-time, on-site decision making, reducing reliance on centralised laboratories and minimising sample degradation and handling errors. This review examines recent progress in materials, such as carbon and its derivatives, sensing strategies, and application-specific performance metrics, and highlights current challenges and unmet needs in forensic applications. Collectively, these developments underscore the growing role of nanomaterials-based sensing technologies in strengthening evidentiary reliability and advancing modern forensic investigations.
