Atomically dispersed transition metals confined with nitrogen on a carbon support has demonstrated great electrocatalytic performance, but an extremely low concentration of metal atoms (usually below 1.5%) is necessary to avoid aggregation through sintering which limits mass activity. Here, a salt‐template method to fabricate densely populated, monodispersed cobalt atoms on a nitrogen‐doped graphene‐like carbon support is reported, and achieving a dramatically higher site fraction of Co atoms (≈15.3%) in the catalyst and demonstrating excellent electrocatalytic activity for both the oxygen reduction reaction and oxygen evolution reaction. The atomic dispersion and high site fraction of Co provide a large electrochemically active surface area of ≈105.6 m2 g−1, leading to very high mass activity for ORR (≈12.164 A mgCo−1 at 0.8 V vs reversible hydrogen electrode), almost 10.5 times higher than that of the state‐of‐the‐art benchmark Pt/C catalyst (1.156 A mgPt−1 under similar conditions). It also demonstrates an outstanding mass activity for OER (0.278 A mgCo−1). The Zn‐air battery based on this bifunctional catalyst exhibits high energy density of 945 Wh kgZn−1 as well as remarkable stability. In addition, both density functional theory based simulations and experimental measurements suggest that the CoN4 sites on the carbon matrix are the most active sites for the bifunctional oxygen electrocatalytic activity.

Trichothecenes are a large family of structurally related toxins mainly produced by Fusarium genus. Among the trichothecenes, T-2 toxin and deoxynivalenol (DON) cause the most concern due to their wide distribution and highly toxic nature. Trichothecenes are known for their inhibitory effect on eukaryotic protein synthesis, and oxidative stress is one of their most important underlying toxic mechanisms. They are able to generate free radicals, including reactive oxygen species, which induce lipid peroxidation leading to changes in membrane integrity, cellular redox signaling, and in the antioxidant status of the cells. The mitogen-activated protein kinases signaling pathway is induced by oxidative stress, which also induces caspase-mediated cellular apoptosis pathways. Several new metabolites and novel metabolic pathways of T-2 toxin have been discovered very recently. In human cell lines, HT-2 and neosolaniol (NEO) are the major metabolites of T-2 toxin. Hydroxylation on C-7 and C-9 are two novel metabolic pathways of T-2 toxin in rats. The metabolizing enzymes CYP3A22, CYP3A29, and CYP3A46 in pigs, as well as the enzymes CYP1A5 and CYP3A37 in chickens, are able to catalyze T-2 toxin and HT-2 toxin to form the C-3'-OH metabolites. Similarly to carboxylesterase, CYP3A29 possesses the hydrolytic ability in pigs to convert T-2 toxin to NEO. T-2 toxin is able to down- or upregulate cytochrome P-450 enzymes in different species. The metabolism of DON in humans is region-dependent. Free DON and DON-glucuronide are considered to be the biomarkers for humans. The masked mycotoxin DON-3-β-D-glucoside can be hydrolyzed to free DON in the body. This review will provide useful information on the progress of oxidative stress as well as on the metabolism and the metabolizing enzymes of T-2 toxin and DON. Moreover, the literature will throw light on the blind spots of metabolism and toxicological studies in trichothecenes that have to be explored in the future.

Developing highly efficient electrocatalysts with low cost is critical for the wide‐spread application of sustainable and renewable energy conversion technologies. Single‐atom catalysts (SACs) have attracted considerable attention owing to their high catalytic activity, selectivity, and stability. However, the high surface energy of the single atoms often results in an extremely low loading of metal atom catalysts with limited mass activity. In this context, densely populated SACs are more promising for practical applications due to their high active surface area and mass activity. Herein, the recent research progress of high loading (≥5 wt%) SACs for different electrocatalytic applications is summarized. An overview of various synthesis and characterization strategies of SACs is presented in this review. The influence of appropriate substrates on the preparation of high metal loading SACs is also discussed. In addition, this review provides valuable insights into the current challenges and future opportunities in the field of single‐atom catalysts.