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Economical and efficient electrocatalysts are crucial to the hydrogen evolution reaction (HER) in water splitting to produce hydrogen. Heterostructured electrocatalysts generally exhibit enhanced HER catalytic activity due to the strong electron coupling effects and synergistic optimization of hydrogen adsorption–desorption. Herein, in-plane heterostructured MoN/Mo2N nanosheets are fabricated as high-efficiency HER electrocatalysts in the alkaline medium from bulk MoS2 by molten salt-assisted synthesis. Density-functional theory calculations and experiments show that the in-plane heterostructured MoN/Mo2N nanosheets facilitate interfacial electron redistribution from Mo2N to MoN, giving rise to more negative H2O adsorption energy and optimal hydrogen adsorption free energy (ΔGH* = −0.017 eV). Consequently, a low overpotential of 126 mV at 10 mA cm−2 and a small Tafel slope of 69.5 mV dec−1 are achieved in the 1M KOH electrolyte, demonstrating excellent HER characteristics. Moreover, the overpotential shows negligible change after operating at 50 mA cm−2 for 12 h, confirming the excellent stability. The results reveal a novel and effective strategy to design highly efficient 2D in-plane heterostructured HER electrocatalysts for water splitting.

Electrocatalytic urea oxidation reaction (UOR) is regarded as an effective yet challenging approach for the degradation of urea in wastewater into harmless N2 and CO2. To overcome the sluggish kinetics, catalytically active sites should be rationally designed to maneuver the multiple key steps of intermediate adsorption and desorption. Herein, we demonstrate that metal-organic frameworks (MOFs) can provide an ideal platform for tailoring binary active sites to facilitate the rate-determining steps, achieving remarkable electrocatalytic activity toward UOR. Specifically, the MOF (namely, NiMn0.14-BDC) based on Ni/Mn sites and terephthalic acid (BDC) ligands exhibits a low voltage of 1.317 V to deliver a current density of 10 mA cm-2. As a result, a high turnover frequency (TOF) of 0.15 s-1 is achieved at a voltage of 1.4 V, which enables a urea degradation rate of 81.87% in 0.33 M urea solution. The combination of experimental characterization with theoretical calculation reveals that the Ni and Mn sites play synergistic roles in maneuvering the evolution of urea molecules and key reaction intermediates during the UOR, while the binary Ni/Mn sites in MOF offer the tunability for electronic structure and d-band center impacting on the intermediate evolution. This work provides important insights into active site design by leveraging MOF platform and represents a solid step toward highly efficient UOR with MOF-based electrocatalysts.

Silicon is a promising anode material for lithium-ion batteries but experiences large volume changes during cycling. Here the authors report a scalable method to synthesize porous ant-nest-like silicons. The unique structure of this anode solves the swelling problem and enables impressive performance.

Development of efficient electrocatalysts combining the features of low cost and high performance for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) still remains a critical challenge. Here, we proposed a facile strategy to construct in situ a novel hierarchical heterostructure composed of 0D−2D CoSe2/MoSe2 by the selenization of CoMoO4 nanosheets grafted on a carbon cloth (CC). In such integrated structure, CoSe2 nanoparticles dispersed well and tightly bonded with MoSe2 nanosheets, which can not only enhance kinetics due to the synergetic effects, thus promoting the electrocatalytic activity, but also effectively improve the structural stability. Benefiting from its unique architecture, the designed CoSe2/MoSe2 catalyst exhibits superior OER and HER performance. Specifically, a small overpotential of 280 mV is acquired at a current density of 10 mA·cm−2 for OER with a small Tafel slope of 86.8 mV·dec−1, and the overpotential is 90 mV at a current density of 10 mA·cm−2 for HER with a Tafel slope of 84.8 mV·dec−1 in 1 M KOH. Furthermore, the symmetrical electrolyzer assembled with the CoSe2/MoSe2 catalysts depicts a small cell voltage of 1.63 V at 10 mA·cm−2 toward overall water splitting.

Background/aims: Nitric oxide (NO) production is elevated in the intestine and may contribute to intestinal injury during inflammation. However, how the expression of inducible NO synthase (iNOS) mRNA and endothelial NO synthase (eNOS) mRNA in the esophageal mucosa contribute to mucosal damage caused by reflux esophagitis remains unknown. Since vascular endothelial growth factor (VEGF) exerts its action on microcirculation, contributing to angiogenesis and inflammation, we examined the role of VEGF together with iNOS and eNOS on development of reflux esophagitis., Methodology: The mRNA expression levels of iNOS, eNOS and VEGF were measured in biopsy specimens from 25 patients with reflux esophagitis, using TaqMan PCR and reverse transcription PCR., Results: The expression of iNOS mRNA in the esophageal mucosa increased parallel to the severity of the esophagitis. There were no significant differences between both eNOS and VEGF mRNA expression levels and the severity of the esophagitis. The existence of gastric mucosal atrophy, hiatus hernia, therapy and Helicobacter pylori infection did not affect the levels of mRNA expression., Conclusions: The accumulation of NO, produced by iNOS, was considered to be related to the exacerbation of reflux esophagitis. Therapeutic intervention that reduces NO production may thus be of use in preventing development of esophageal mucosal injury in patients with reflux esophagitis.

Background: Recent studies have shown that the number of patients with reflux esophagitis is increasing in Japan, but the prevalence and risk factors associated with reflux esophagitis in Japanese patients are not well defined., Methods: By using all endoscopic records in the Katta General Hospital from April through to September 1999, we identified 392 patients. We examined the Los Angeles classification, peptic ulcer, gastric mucosal atrophy, hiatal hernia and other medical variable factors for their contribution to esophagitis in the patients., Results: Patients (13.8%) were diagnosed as having reflux esophagitis with a mucosal break. In a multivariate analysis, reflux esophagitis was associated with hiatal hernia (odds ratio (OR) 2.276, 95% confidence interval (CI) 1.164-4.450), with patients over 65 years of age (OR 2.521, 95% CI 1.238-5.134) and the open type of gastric mucosal atrophy (OR 0.420, 95% CI 0.225-0.785). There was no significant difference between esophagitis and Helicobacter pylori infection and peptic ulcer., Conclusions: We observed that age, hiatal hernia and a lower rate of gastric mucosal atrophy were associated with the proportion of mucosal breaks accompanying esophagitis.