Graphene is a single atomic plane of sp²-bound carbon that has attracted considerable interest in various technologies. On the basis of its unique physical, mechanical, and chemical properties, graphene is a potentially strong candidate as a lubricant additive in its liquid-based form to reduce friction and protect surfaces from degrading. Furthermore, graphene on wear performance acts as a heat dissipation source for liquid lubricants. This review explores and addresses the fundamental mechanisms illuminating the exceptional tribological behaviours of graphene family materials and their limitations. Although graphene additives were reported to improve friction coefficients and wear properties, several challenges remain a hindrance, such as production costs, dispersion stability, and lack of information regarding graphene optimisation. Thus, this review can provide a standard methodological framework for graphene additives in improving tribological performance. Moreover, this review provides an up-to-date review of current tribological experiments based on ultrafine particles incorporated with graphene as an additive for lubricating liquids.

Environmental sensors play a crucial role in a wide range of applications. Amongst them, humidity sensors that are stable and operational in harsh environments are incredibly important for process control and monitoring. Nanocrystalline graphite (NCG) is a type of carbon-based thin film material. Previous work has shown that NCG has excellent mechanical properties and is able to withstand high radiation doses. The granular structure of the NCG film makes it a good candidate for humidity sensing as the film consists of conductive graphitic grains with a high density of sp2 bonds and amorphous grain boundaries with high resistivity, adsorption of water molecule onto the film forms conductive pathways between grains through the Grotthuss mechanism which lowers the resistance of the film by a measurable amount. Here we report for the first time, a working humidity sensor with linear response, fabricated using NCG as the sensing material for harsh, real-world environments, which include exposure to weak acids via rainfall, UV radiation, mechanical wear, and high humidity environments. The calculated sensitivity of the best-fabricated sensor is S = 0.0334%, with a maximum resistance change of -4.4 kOhms, over the range of 15% RH to 85% RH. The response time of the sensor is 20ms with the current measurement setup. The baseline resistance value of the sensor at 15% RH is 210 kOhms. The sensor has the potential to be used as a humidity sensor for harsh environments due to the chemical, thermal and mechanical stability of the NCG film.

Laser-induced graphene (LIG) electrodes have gained interest for non-enzymatic analyte sensing applications due to their low cost, flexibility, and favorable electrochemical properties. In this study, we investigate the effects of Ag and Pt nanoparticle (NP) surface modification on the capacitive glucose sensing performance of LIG electrodes. LIG was fabricated at varying laser fluences and subsequently decorated with different NP loadings to evaluate interfacial capacitance changes in 1 M KCl electrolyte. Electrochemical characterization revealed that a 10 μg ml ⁻¹ NP loading concentration yielded the highest sensitivity — 0.0449 and 0.052 mF (mM·cm) ⁻² for Ag- and Pt-modified LIG, respectively — with the lowest detection limit of 1.29 μM achieved by Ag-LIG. Although the study is limited to controlled electrolyte conditions without interference or selectivity tests, the results demonstrate a measurable enhancement in glucose sensitivity compared to pristine LIG. These findings support the potential of metal-NP loaded LIG for cost-effective glucose sensing in high-concentration environments such as food fermentation monitoring.