In the past 10–15 years, the microbial fuel cell (MFC) technology has captured the attention of the scientific community for the possibility of transforming organic waste directly into electricity through microbially catalyzed anodic, and microbial/enzymatic/abiotic cathodic electrochemical reactions. In this review, several aspects of the technology are considered. Firstly, a brief history of abiotic to biological fuel cells and subsequently, microbial fuel cells is presented. Secondly, the development of the concept of microbial fuel cell into a wider range of derivative technologies, called bioelectrochemical systems, is described introducing briefly microbial electrolysis cells, microbial desalination cells and microbial electrosynthesis cells. The focus is then shifted to electroactive biofilms and electron transfer mechanisms involved with solid electrodes. Carbonaceous and metallic anode materials are then introduced, followed by an explanation of the electro catalysis of the oxygen reduction reaction and its behavior in neutral media, from recent studies. Cathode catalysts based on carbonaceous, platinum-group metal and platinum-group-metal-free materials are presented, along with membrane materials with a view to future directions. Finally, microbial fuel cell practical implementation, through the utilization of energy output for practical applications, is described.

As highlighted by the recent roadmaps from the European Union and the United States, water electrolysis is the most valuable high‐intensity technology for producing green hydrogen. Currently, two commercial low‐temperature water electrolyzer technologies exist: alkaline water electrolyzer (A‐WE) and proton‐exchange membrane water electrolyzer (PEM‐WE). However, both have major drawbacks. A‐WE shows low productivity and efficiency, while PEM‐WE uses a significant amount of critical raw materials. Lately, the use of anion‐exchange membrane water electrolyzers (AEM‐WE) has been proposed to overcome the limitations of the current commercial systems. AEM‐WE could become the cornerstone to achieve an intense, safe, and resilient green hydrogen production to fulfill the hydrogen targets to achieve the 2050 decarbonization goals. Here, the status of AEM‐WE development is discussed, with a focus on the most critical aspects for research and highlighting the potential routes for overcoming the remaining issues. The Review closes with the future perspective on the AEM‐WE research indicating the targets to be achieved.

Two iron-based platinum group metal-free catalysts for the oxygen reduction reaction (ORR) were synthesized from novel and low cost organic precursors named niclosamide and ricobendazole. These catalysts have been characterized, incorporated in a gas diffusional electrode and tested in “clean” conditions as well as in operating microbial fuel cell (MFC) for 32 days. Both catalysts demonstrated unprecedented performance yielding a power density 25% higher than that of platinum (Pt) and roughly 100% higher than activated carbon (AC) used as a control. Durability tests were performed and showed that Pt-based cathodes lost their activity within the first week of operation, reaching the level of the supporting AC-based electrode. Fe–ricobendazole, however, demonstrated the highest performance during the long-term study with a power density of 195 ± 7 μW cm⁻² (day 2) that slightly decreased to 186 ± 9 μW cm⁻² at day 29. Fe–niclosamide also outperformed Pt and AC but the power density roughly decreased with 20% for the 32 days of the study. Accelerated poisoning test using S²⁻ as pollutant showed high losses in activity for Pt. Fe–niclosamide suffered higher losses compared to Fe–ricobendazole. Importantly, Fe–ricobendazole represents a 55-fold cost reduction compared to platinum.

Several organic precursors have been used to fabricate Fe-based catalysts using sacrificial support method. Those catalysts were then included in air breathing cathodes for microbial fuel cells working at neutral environment. Electrochemical performances and surface chemistry were measured and related.