ABSTRACT
Developing non-noble metal-based core-shell heterojunction electrocatalysts with high catalytic activity and long-lasting stability is crucial for the oxygen evolution reaction (OER). Here, we prepared novel core-shell Fe,V-NiSe2@NiFe(OH)x heterostructured nanoparticles on hydrophilic-treated carbon paper with high electronic transport and large surface area for accelerating the oxygen evolution rate via high-temperature selenization and electrochemical anodic oxidation procedures. Performance testing shows that Fe,V-NiSe2@NiFe(OH)x possesses the highest performance for OER compared to as-prepared diselenide core-derived heterojunctions, which only require an overpotential of 243 mV at 10 mA cm-2 and a low Tafel slope of 91.6 mV decade-1 under basic conditions. Furthermore, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) confirm the morphology and elementary stabilities of Fe,V-NiSe2@NiFe(OH)x after long-term chronopotentiometric testing. These advantages are largely because of the strong synergistic effect between the Fe,V-NiSe2 core with high conductivity and the amorphous NiFe(OH)x shell with enriched defects and vacancies. This study also presents a general approach to designing and synthesizing more active core-shell heterojunction electrocatalysts for OER.
ABSTRACT
Lonicerae Japonicae Flos and Lonicerae Flos, as traditional Chinese medicinal and edible food, are widely used in medicine, food, health products, and other industries. However, there is no comprehensive study on the differences of flavor compounds in Lonicerae Japonicae Flos and Lonicerae Flos. This study applied headspace gas chromatography-ion mobility spectrometry(HS-GC-IMS) to analyze the differences of flavor compounds in Lonicerae Japonicae Flos and Lonicerae Flos. The differential biomarkers were confirmed by multivariate statistical analysis. The results showed that there were significant differences in the forty-seven flavor compounds in Lonicerae Japonicae Flos and Lonicerae Flos. The differential markers were ethyl acetate, propyl alcohol, 1-octanol, 1-hexanol, hexanal, and(Z)-2-hexen-1-ol. Pathway enrichment analysis showed that the above markers were involved in the biosynthesis of major secondary metabolism, sulfate metabolism pathways, and formation of other flavor compounds. This study provides important references for the evaluation of flavor compounds of Lonicerae Japonicae Flos and Lonicerae Flos and the development of medicinal and edible products.