Vol. 2 No. 3 (2024)

The reliance on fossil fuels has led to numerous environmental challenges, highlighting the urgent need for alternative energy sources that minimize contamination and promote eco-friendliness. In this context, hydrogen (H₂) emerges as a promising fuel due to its zero-carbon emissions. Within various methods for H₂ production, electrochemical water splitting (EWS) stands out as a viable approach. Traditionally, noble metals, such as platinum and iridium, have been employed as electrocatalysts to efficiently facilitate the hydrogen evolution reaction (HER) in desired electrolytes (such as alkaline). Recently, research has focused on the use of Prussian blue (PB) as an innovative electrocatalyst material for EWS. Herein, we developed PB-based electrocatalysts for HER in an alkaline medium. The electrocatalyst comprising PB combined with phosphorus exhibited impressive electrochemical properties, achieving a minimal overpotential of 103 mV at a current density of 10 mA/cm² and maintaining durability over 20 h, along with extended electrochemical performance. This material composition has considerable promise as a potential option for energy conversion systems, which can aid future sustainability initiatives.

This article examined the effectiveness of bioclimatic strategies to enhance thermal comfort and decrease energy consumption in a desert-climate residence. The study assessed the impact of thermal insulation, natural ventilation, and phase-change materials (PCMs) over a year, with each strategy evaluated both independently and in combination. Monthly energy bills were analyzed to determine the impact of these strategies. The results indicated substantial reductions in energy costs, with decreases of up to 50% during transitional seasons; however, the complete elimination of heating and cooling systems was not feasible due to significant thermal phase differences between indoor and outdoor environments. Further analysis of thermal discomfort hours revealed that increasing insulation thickness during specific seasons could mitigate peak heat intensity and delay its occurrence, thus extending periods of comfort and reducing discomfort hours. Despite these improvements, some periods of thermal distress persisted during the warmest months, underscoring the necessity for a balanced approach to climate adaptation strategies. Overall, the implementation of these strategies proved effective in improving comfort and reducing energy usage in desert-climate homes, although they do not fully negate the need for traditional heating and cooling systems.

A high-performance, fish-friendly bulb turbine was developed in this study by optimizing a runner with spiral blades to enhance the flow passage for fish. The key aspect of this work is multi-objective optimization based on the orthogonal method. Four factors were focused on: the number of guide vanes, the wedge angle of the blades, the distance of vaneless space, and the pitch variation ratio. The optimal value of each design parameter was determined through comprehensive measurements, including intuitive analysis, range analysis, and synthetical frequency analysis. The evaluating indexes were unit output, efficiency, fish-passing damage rate, pressure fluctuation, maximum blade deformation, and equivalent stress. The results indicate that the pitch ratio parameter significantly affected hydraulic performance, while the number of guide vanes primarily influenced fish-passing performance. The optimized turbine achieved a hydraulic efficiency of 84.05%, with a fish damage rate of only 0.01%. Structurally, the vibration modes of the runner were mainly oscillating deformation, rotating deformation around the axis, and bending deformation. The difference between the hydraulic excitation frequencies and the natural frequencies of the runner exceeded 20%, ensuring no resonance under the best efficiency point (BEP) condition. The dry and the prestressed modals showed similar natural frequencies and vibration patterns for the runner, whereas the wet modal showed higher natural frequencies for the runner.

During this investigation, the variation of the water evaporation phenomenon with the defined drying temperature and mass of water was analyzed, five levels were studied (50, 60, 70, 80 and 90 ℃), finally a correlation between temperature and evaporation rate was generated. With the study carried out, it was defined that the water evaporation velocity can be calculated with an initial mass of 35 g at 90 ℃, while the necessary time for the determination was 120 min. In addition, it was determined that the evaporation velocity follows a quadratic behavior with temperature, according to the experiments carried out with the Sartorius MA-100 balance, while the maximum deviation recorded was 0.349 mmol/m²s for a temperature of 80 ℃. It is concluded that the determination of the water evaporation velocity is highly dependent on the temperature and mass of water. Furthermore, this study can be used as a basis for future studies aimed at improving the efficiency of processes such as steam and electricity cogeneration.

Hydrogen (H₂) plays a crucial role in the transformation of the energy structure due to its environmental friendliness, renewability and high energy density. The photocatalytic and electrocatalytic hydrogen evolution reaction (HER) presents a promising approach for H₂ production. Molybdenum disulfide (MoS₂) has emerged as a promising catalyst in photocatalytic and electrocatalytic HER due to its high activity, easy preparation and cheapness. However, it suffers from poor stability and inactive basal planes. In this review, we encapsulated the research advancements of MoS₂ for photocatalytic and electrocatalytic HER in the past ~10 years. The latest strategies to enhance the catalytic activity of MoS₂, such as doping, phase adjustment, surface modification and others, are also summarized. The relationship between structure and activity for enhanced H₂ generation by different means is briefly introduced. The challenges and directions of MoS₂ materials in photocatalysis and electrocatalysis for HER are also discussed, aiming to provide promising guidelines for future research.

The escalating global demand for sustainable energy has propelled the exploration of biohydrogen production with a promising avenue for simultaneously generating clean energy and managing waste effectively. This review mainly focuses on advances in sustainable biohydrogen production from saline wastewater, especially in a process that leverages the unique abilities of halotolerant and halophilic microorganisms adapted to high-salinity conditions. It provides an extensive understanding of various biohydrogen production methods, which are biophotolysis, photofermentation, dark fermentation, and microbial electrolysis. Additionally, this review elaborated on the enzymology of hydrogen production and the impact of salt stress, with a particular emphasis on the adaptive mechanisms of “salt-in” and “compatible solute” strategies. These adaptations are crucial for maintaining enzymatic activity and structural integrity under hypertonic conditions. Through a comprehensive examination of microbial pathways and strategies, this review aimed to furnish foundational insights that will drive future research and technological innovations in biohydrogen production.

Photocatalysis is of particular interest because it can be utilized for reducing air pollution and decreasing greenhouse gas emissions. This review examined the latest advances in layered photocatalytic nanomaterials and single-atom catalysts and discloses the synthesis, structural features, and ways to enhance their catalytic ability. In particular, we describe the peculiarities of catalysis mechanisms in CO₂ conversion, pollutant and NO_x removal, and nitrogen reduction. The current trends in this field and the potential areas for further research are also discussed in this review. It is important to emphasize that single-atom catalysts possess distinct advantages to substantially improve the efficiency of energy conversion processes. The materials related to the synthesizing and post-processing of layered semiconductor catalysts and single-atom catalysts can be useful for other researchers and stakeholders.

The daily well-being of modern humanity is closely linked to the use of different devices operating through different sources of energy conversion. Electromagnetic energy obtained from the conversion of clean energy is one of the most used in devices in this context. The use of these devices reflects the expected results, often accompanied by unwanted side effects. These undesirable side effects correspond to the interaction of artificial electromagnetic radiation with living tissues of biodiversity (One Health concept). The corresponding living tissues are related to humans, animals (domestic and wild), birds, plants, etc., and more generally to biodiversity, including the ecosystem. Therefore, these harmful effects could be reduced by intelligent and sustainable construction and protection (Responsible Attitude concept) of these devices. This article aimed to illustrate the implication of the concepts of One Health and Responsible Attitude in the management of the daily use of wireless communication tools with electromagnetic energy, as well as power transfer devices. The two concepts were first discussed. The biological effects on living tissues due to exposure to electromagnetic field radiation were analyzed in the case of humans, animals and plants. The different characteristics of the radiated field and exposed tissues influencing these effects, as well as the governing laws and mathematical modeling of the effects, were examined. Additionally, the means for protecting living tissues from electromagnetic radiation were inspected. The analyses pursued in this article were supported by examples taken from the literature.

Utilizing synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) to capture intermediates has significantly enhanced the understanding of catalytic reactions. This commentary introduced the structure of SVUV-PIMS and then revisited an excellent work in science that utilized SVUV-PIMS to elucidate the mechanisms of dimethyl oxalate (DMO) hydrogenation into ethylene glycol over copper nanoparticles (Cu NPs) supported on dealuminated Beta zeolite (Beta-deAl). The observation of key intermediates, particularly (CHO)Cu₁^* species, using SVUV-PIMS provided real-time, in-situ insights into the dynamic behavior of Cu NPs in DMO hydrogenation. The findings highlighted the formation of a silanol nest and the presence of metallic Cu and Cu₂O phases following methanol treatment. This treatment helped maintain a small nanoparticle size, resulting in high EG yields and prolonged catalyst stability. Additionally, their catalyst addressed common issues, such as silica leaching, which often compromises the durability of CuSiO₂-based catalysts. By re-examining their work, this commentary underscores the transformative potential of SVUV-PIMS in catalysis research, and the operando adaptation of intermediates in reactions is invaluable for developing more efficient and durable catalysts.

Prof. Marc A. Rosen is a Professor of Mechanical & Manufacturing Engineering at Ontario Tech University (formally University of Ontario Institute of Technology) in Oshawa, Canada, where he served as founding Dean of the Faculty of Engineering and Applied Science. Prof. Rosen has served as President of the Engineering Institute of Canada and of the Canadian Society for Mechanical Engineering. He has received numerous awards and honors, including an Award of Excellence in Research and Technology Development from the Ontario Ministry of Environment and Energy, the Engineering Institute of Canada Smith Medal for achievement in the development of Canada, and the Canadian Society for Mechanical Engineering Angus Medal for outstanding contributions to the management and practice of mechanical engineering. Prof. Rosen received a distinguished scholar award from Toronto Metropolitan University (formerly Ryerson University) and a Mid-Career Award from University of Toronto. He is a fellow of the Royal Society of Canada, the Engineering Institute of Canada, the Canadian Academy of Engineering, the Canadian Society for Mechanical Engineering, the American Society of Mechanical Engineers and the International Energy Foundation.