Microbial Electrochemistry Technology (MET) leverages the unique process of extracellular electron transfer (EET) between electroactive bacteria (EAB) and electrodes to enable various applications, such as electricity generation, bioremediation, and wastewater treatment. This review highlights significant advancements in EET mechanisms, emphasizing both outward and inward electron transfer pathways mediated by diverse electroactive microorganisms. Notably, the role of electron shuttles, genetic modifications, and innovative electrode materials are discussed as strategies to enhance EET efficiency. Recent studies illustrate the importance of redox-active molecules, such as flavins and metal nanoparticles, in facilitating electron transfer, while genetic engineering has proven effective in optimizing microbial physiology to boost EET rates. The review also examines the impact of electrode materials on microbial attachment and performance, showcasing new composites and nanostructures that enhance power output in microbial fuel cells. By synthesizing the recent findings and proposing emerging research directions, this work provides an overview of EET enhancement strategies, aiming to inform future technological innovations in bioelectrochemical systems (BESs).

In this work, the catalytic performance of clinoptilolite (CLIN) and SBA-15 catalysts, doped with Fe and Cu, was evaluated in the selective catalytic reduction of NO using NH₃ as a reducing agent (SCR-NH₃). Both Cu-CLIN and Fe-CLIN were obtained by ion-exchange using natural clinoptilolite zeolite originating from the Hrabovec deposit (northeast Slovakia region). Cu-SBA-15 and Fe-SBA-15 were prepared by impregnation into SBA-15 mesoporous synthesized silica. Standard catalytic activity tests were carried out on a bench-scale laboratory apparatus using a reaction mixture of a standard test. GHSV of 48,000 h⁻¹ was adopted based on the space velocity of a real NH₃-SCR catalyst for diesel vehicles (100–550 °C). All Cu-doped samples showed better NO conversion values than Fe-doped samples. Clinoptilolite catalysts were more active than those based on SBA-15. Maximum NO conversions of about 96% were observed for Cu-CLIN and Fe-CLIN at 350–400 °C, respectively. Moreover, Fe-CLIN also showed higher stability in the presence of SO₂ and water steam at 350 °C. These results demonstrate the potential of metal-doped natural clinoptilolite to be used as cost-effective catalysts applied to the abatement of NOx emissions generated in automotive combustion processes.

Objective: The objective of this study is the development of the basic guidelines for blending green hydrogen with natural gas and transporting it through the gas pipelines of a natural gas distribution company. The characteristics of consumption, legislation and materials used in the company's network were considered. In addition, data from recent research in the area was also selected to support specific actions so that this objective is achieved in a technically sustainable way, respecting technical knowledge and standards available internationally. Method: In this scenario, a study of the feasibility of enriching natural gas distributed by a gas distribution company in the region of the city of Fortaleza with green hydrogen is presented. In addition, data from recent research in the area was also selected to support specific actions so that this objective is achieved in a technically sustainable way, respecting technical knowledge and standards available internationally. Results and Discussion: Based on current legislation and a series of technical references, it is currently recommended to add levels of up to 2% in branches where natural gas is used for vehicular and industrial glass and ceramic applications and can increase up to 3% in other extensions. The maximum concentration may reach 10% in the medium term after detailed fatigue resistance studies or adaptation of pipes with internal polymer jackets. Research Implications: The interest in replacing fossil fuels for decarbonization purposes has motivated research into a series of alternatives, among which hydrogen stands out as a possible vector or energy carrier for high-efficiency systems with oxidation free of carbon emissions. carbon. Introducing renewable hydrogen into natural gas distribution networks stabilizes the demand for production of this gas, in addition to alleviating the costs and risks associated with building a dedicated facility. Originality/Value: This study contributes to the literature related to the study of green Hydrogen. The relevance and value of this research are evidenced by the results obtained.