Revealing the mechanisms of alkali-based magnetic nanosheets enhanced hydrogen production from dark fermentation: Comparison between mesophilic and thermophilic conditions

Metals have been used as antimicrobial agents since antiquity, but throughout most of history their modes of action have remained unclear. Recent studies indicate that different metals cause discrete and distinct types of injuries to microbial cells as a result of oxidative stress, protein dysfunction or membrane damage. Here, we describe the chemical and toxicological principles that underlie the antimicrobial activity of metals and discuss the preferences of metal atoms for specific microbial targets. Interdisciplinary research is advancing not only our understanding of metal toxicity but also the design of metal-based compounds for use as antimicrobial agents and alternatives to antibiotics. Show more

3D core–shell nanostructures of few-layer NiFe LDH nanosheets grown on Cu nanowires are fabricated toward highly efficient overall water splitting. Developing highly active and low-cost electrocatalysts with superior durability for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is a grand challenge to produce hydrogen by electrolysis of water. Here, we report on a facile and scalable approach to fabricate highly efficient three-dimensional (3D) bulk catalysts of core–shell nanostructures, in which few-layer NiFe layered double hydroxide (LDH) nanosheets are grown on Cu nanowire cores supported on Cu foams, toward overall water splitting. Remarkably, benefiting from the 3D hierarchical nanoarchitecture with large surface areas, fast electron transport, and open-channels for effective gas release, the resulting 3D self-standing catalysts exhibit outstanding OER activity as well as excellent HER performance in an alkaline medium. Using them as bifunctional catalysts for overall water splitting, a current density of 10 mA cm −2 was achieved at a voltage of 1.54 V, and 100 mA cm −2 at 1.69 V with excellent durability, which is much better than the benchmark of IrO 2 (+)//Pt(−) electrodes. Our 3D core–shell electrocatalysts significantly advance the research towards large-scale practical water electrolysis. Show more

Globally increasing energy demands and environmental concerns related to the use of fossil fuels have stimulated extensive research to identify new energy systems and economies that are sustainable, clean, low cost, and environmentally benign. Hydrogen generation from solar-driven water splitting is a promising strategy to store solar energy in chemical bonds. The subsequent combustion of hydrogen in fuel cells produces electric energy, and the only exhaust is water. These two reactions compose an ideal process to provide clean and sustainable energy. In such a process, a hydrogen evolution reaction (HER), an oxygen evolution reaction (OER) during water splitting, and an oxygen reduction reaction (ORR) as a fuel cell cathodic reaction are key steps that affect the efficiency of the overall energy conversion. Catalysts play key roles in this process by improving the kinetics of these reactions. Porphyrin-based and corrole-based systems are versatile and can efficiently catalyze the ORR, OER, and HER. Because of the significance of energy-related small molecule activation, this review covers recent progress in hydrogen evolution, oxygen evolution, and oxygen reduction reactions catalyzed by porphyrins and corroles. Show more