High entropy alloys (HEAs) have gained significant attention in electrocatalysis research due to their distinctive multi-element composition, intricate electronic structure, and superior properties. By harnessing multi-component synergy, precise electron regulation, and the high-entropy effect, HEA electrocatalysts exhibit remarkable catalytic activity, selectivity, and stability. These materials demonstrate outstanding catalytic performance in a variety of electrocatalytic small molecule reduction reactions, including oxygen reduction (ORR), hydrogen evolution (HER), and CO₂ reduction (CO₂RR), making them promising candidates for clean energy conversion and storage applications, including fuel cells, metal-air batteries, water electrolysis, and CO₂ conversion technologies. This review highlights recent advancements in HEA electrocatalyst research, focusing on their synthesis, characterization, and applications in electrocatalytic small molecule reduction reactions. It also explores the underlying mechanisms of the high-entropy effect, multi-component synergy, and structural design. Finally, it discusses key challenges that remain in the application of HEAs for electrocatalytic small molecule reduction and outlines potential directions for future development in this field.

NH₃ has emerged as a promising candidate for low-carbon gas turbines, with NO_x emission issues being mitigated by air-staged combustion. However, the role of fuel/air mixing quality (represented by unmixedness) in NO_x formation in NH₃ systems remains poorly explored. In this study, the characteristics of NO_x formation under the effects of unmixedness have been numerically investigated using an NH₃/CH₄ fired air-staged model combustor consisting of perfectly stirred reactors (PSRs) and plug flow reactors (PFRs), employing the 84-species, 703-reaction Tian mechanism under H/J heavy duty gas turbine conditions. It was found that a primary-stage equivalence ratio of 1.2–1.5 corresponds to a low NO_x formation region under perfectly mixed fuel and air conditions. In this region, a relatively low NO_x formation is achieved when the unmixedness is less than 0.12 and NO_x formation exhibits low sensitivity to fuel/air unmixedness. Based on these findings and the fact that the air-staged combustion loses its advantage in reducing NO_x emissions when the unmixedness exceeds 0.12 across all equivalence ratios, recommended mixing quality thresholds for different equivalence ratios are proposed to guide combustor design and operation optimization. A parametric study of chemical reaction pathways at different unmixedness levels in the two stages demonstrates that NO_x is mainly formed in the main combustion zone of the secondary stage via the HNO pathway, which results in NO_x formation rising to thousand ppm when unmixedness exceeds 0.3, although NO_x reduction through NHi and N₂O pathways partially offsets contributions from the HNO and thermal NO_x pathways. To leverage the NO_x reduction potential of the NH_i and N₂O pathways, the residence time in both stages should be carefully adjusted to help suppress NO_x to as low as 48 ppm. The results of this study are important for engineering applications, providing guidance for the design of NH₃ fired combustors aimed at significantly reducing NO_x formation.

Fiber-shaped energy storage devices (FSESDs) with exceptional flexibility for wearable power sources should be applied with solid electrolytes over liquid electrolytes due to short circuits and leakage issue during deformation. Among the solid options, polymer electrolytes are particularly preferred due to their robustness and flexibility, although their low ionic conductivity remains a significant challenge. Here, we present a redox polymer electrolyte (HT_RPE) with 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (HT) as a multi-functional additive. HT acts as a plasticizer that transforms the glassy state into the rubbery state for improved chain mobility and provides distinctive ion conduction pathway by the self-exchange reaction between radical and oxidized species. These synergetic effects lead to high ionic conductivity (73.5 mS cm⁻¹) based on a lower activation energy of 0.13 eV than other redox additives. Moreover, HT_RPE with a pseudocapacitive characteristic by HT enables an outstanding electrochemical performance of the symmetric FSESDs using carbon-based fiber electrodes (energy density of 25.4 W h kg⁻¹ at a power density of 25,000 W kg⁻¹) without typical active materials, along with excellent stability (capacitance retention of 91.2% after 8,000 bending cycles). This work highlights a versatile HT_RPE that utilizes the unique functionality of HT for both the high ionic conductivity and improved energy storage capability, providing a promising pathway for next-generation flexible energy storage devices.

In an innovative twist to sustainable agriculture, a new study reveals how sugarcane waste can be transformed into biochar—a powerful soil amendment that enhances soil quality. This research not only highlights a green approach to waste management but also provides a significant boost to soil health, offering a win-win for both the environment and farming practices.

Chemists have long been fascinated and frustrated by saxitoxin: a molecule that causes temporary paralysis by blocking the electrical signals that nerve cells (neurons) use to activate muscle, and which accumulates in shellfish like clams, oysters and scallops. Although the way saxitoxin works has inspired interest in developing new anesthetics, extracting it from natural sources is neither scalable nor practical. Since its discovery, the molecule has defied practical laboratory synthesis, slowing the effort to create long-acting, highly targeted pain therapies inspired by its mechanism. Now, scientists at Scripps Research, in collaboration with Merck, report a streamlined approach to synthesize saxitoxin and related molecules (known as analogs) in the lab.

A new electrocatalyst combining iron phthalocyanine (FePc) with mesoporous Ti₃C₂ MXene significantly enhances oxygen reduction reaction (ORR) performance under alkaline conditions, achieving higher activity and stability than commercial platinum-based catalysts, and demonstrating great potential for application in zinc-air batteries.  

Understanding how ozone behaves indoors is vital for assessing human health risks, as people spend most of their time inside. 

Proton exchange membrane fuel cells (PEMFCs) have attracted significant attention as sustainable energy technologies due to their efficient energy conversion and fuel flexibility. However, several challenges remain, such as low catalytic activity of fuel cell membrane electrode assembly (MEA), insufficient mass transfer performance, and performance degradation caused by catalyst deactivation over long period of operation. These issues are especially significant at high current densities, limiting both efficiency and operational lifespan. Mesoporous carbon materials, characterized by a high specific surface area, tunable pore structure, and excellent electrical conductivity, are emerging as crucial components for enhancing power density, mass transfer efficiency, and durability of PEMFCs. This review first discusses the properties and advantages of mesoporous carbon and outlines various synthetic strategies, including hard template, soft template, and template-free approaches. It then comprehensively examines the applications of mesoporous carbon in PEMFCs, focusing on their effects on the catalyst and gas diffusion layer. Finally, it concludes with future perspectives, emphasizing the need for further research to fully exploit the potential of mesoporous carbon in PEMFCs.

Perovskite-based photovoltaic devices have garnered significant interest owing to their remarkable performance in converting light into electricity. Recently, the focus in the field of perovskite solar cells (PSCs) has shifted towards enhancing their durability over extended periods. One promising strategy is the incorporation of two-dimensional (2D) perovskites, known for their ability to enhance stability due to the large organic cations that act as a barrier against moisture. However, the broad optical bandgap and limited charge transport properties of 2D perovskites hinder their efficiency, making them less suitable as the sole light-absorbing material when compared to their three-dimensional (3D) counterparts. An innovative approach involves using 2D perovskite structures to modify the surface properties of 3D perovskite. This hybrid approach, known as 2D/3D perovskites, while enhancing their performance. Beyond solar energy applications, 2D perovskites offer a flexible platform for chemical engineering, allowing for significant adjustments to crystal and thin-film configurations, bandgaps, and charge transport properties through the different organic ligands and halide mixtures. Despite these advantages, challenges remain in integration of 2D perovskites into solar cells without compromising device stability. This review encapsulates the latest developments in 2D perovskite research, focusing on their structural, optoelectronic, and stability attributes, while delving into the challenges and future potential of these materials.

Hydrogen is a promising energy carrier that is expected to play a crucial role in helping Canada achieve its net-zero target by 2050. However, reducing the ambiguity in regulatory frameworks is essential to incentivize and facilitate international trade in hydrogen. To this end, regulators must agree on quantification methodologies that consider life cycle boundaries, process descriptions, co-product allocation, conversion constants, and certification units. Several studies have highlighted the importance of life cycle assessment (LCA) as a standardized, relevant method for estimating the carbon footprint associated with hydrogen production and evaluating its environmental sustainability. As such, LCA-based certification schemes could help create a transparent hydrogen market. The aim of this study is to validate the proposed harmonized LCA-based methodology for quantifying hydrogen production’s carbon intensity. This methodology follows a consistent scope and life cycle inventory (LCI) development criteria, alongside a rigorous data quality assessment. The well-to-gate carbon intensities of six hydrogen production pathways are compared, which range from 0.26 to 10.07 kg CO_2e per kg of hydrogen (kg CO_2e/kg H₂), against the hydrogen carbon intensity thresholds established by the Canadian Clean Hydrogen Investment Tax Credit (CHITC). For example, the biomass gasification with carbon capture (CC) pathway demonstrates the lowest carbon intensity, while thermochemical pathways, such as steam methane reforming of natural gas without CC, poses challenges to meeting the maximum CHTIC threshold of 4 kg CO_2e/kg H₂.