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Constructing a low cost, and high-efficiency oxygen evolution reaction (OER) electrocatalyst is of great significance for improving the performance of alkaline electrolyzer, which is still suffering from high-energy consumption. Herein, we created a porous iron phosphide and tungsten oxide self-supporting electrocatalyst with oxygen-containing vacancies on foam nickel (Fe2P-WO2.92/NF) through a facile in-situ growth, etching and phosphating strategies. The sequence-controllable strategy will not only generate oxygen vacancies and improve the charge transfer between Fe2P and WO2.92 components, but also improve the catalyst porosity and expose more active sites. Electrochemical studies illustrate that the Fe2P-WO2.92/NF catalyst presents good OER activity with a low overpotential of 267 mV at 100 mA cm−2, a small Tafel slope of 46.3 mV dec−1, high electrical conductivity, and reliable stability at high current density (100 mA cm−2 for over 60 h in 1.0 M KOH solution). Most significantly, the operating cell voltage of Fe2P-WO2.92/NF || Pt/C is as low as 1.90 V at 400 mA cm−2 in alkaline condition, which is one of the lowest reported in the literature. The electrocatalytic mechanism shows that the oxygen vacancies and the synergy between Fe2P and WO2.92 can adjust the electronic structure and provide more reaction sites, thereby synergistically increasing OER activity. This work provides a feasible strategy to fabricate high-efficiency and stable non-noble metal OER electrocatalysts on the engineering interface.

As the kinetically sluggish oxygen evolution reaction (OER) is considered to be a bottleneck in overall water splitting, it is necessary to develop a highly active and stable electrocatalyst to overcome this issue. Herein, we successfully fabricated a three-dimensional iron-dysprosium oxide co-regulated in-situ formed MOF-Ni arrays on carbon cloth (FeDy@MOF-Ni/CC) through a facile two-step hydrothermal method. Electrochemical studies demonstrate that the designed FeDy@MOF-Ni/CC catalyst requires an overpotential of only 251 mV to reach 10 mA cm−2 with a small Tafel slope of 52.1 mV dec−1. Additionally, the stability declined by only 5.5% after 80 h of continuous testing in 1.0 M KOH. Furthermore, a cell voltage of only 1.57 V in the overall water splitting system is sufficient to achieve 10 mA cm−2; this value is far better than that of most previously reported catalysts. The excellent catalytic performance originates from the unique 3D rhombus-like structure, as well as coupling synergies of Fe-Dy-Ni species. The combination of lanthanide and transition metal species in the synthesis strategy may open entirely new possibilities with promising potential in the design of highly active OER electrocatalysts.

The rational design of non-precious-metal bifunctional catalysts of oxygen and hydrogen evolution reactions that generate a high current density and stability at low over potentials is of great significance in the field of water electrolysis. Herein, we report a facile and controllable method for the in-situ growth of urchin-like FeOOH–NiOOH catalyst on Ni foam (FeOOH–NiOOH/NF). X-ray photoelectron spectroscopy confirms that the proportion of Ni and Fe species with high valence state gradually increase with the extension of growth time. Electrochemical studies have shown that the optimized FeOOH–NiOOH/NF-24 h and −12 h catalysts demonstrate excellent electrochemical activity and stability in oxygen/hydrogen evolution reactions. Moreover, the cell voltage is reduced around 0.15 V at high current density (0.5–1.0 A cm−2) as compared to the state-of the art RuO2/NF(+)||Pt–C/NF(−) system, far better than most of the previously reported catalysts. The cost analyst revealed that using FeOOH–NiOOH/NF catalyst as both electrodes could potentially reduce the price of H2 around 7% compared with traditional industrial electrolyzers. These excellent electrocatalytic properties can be attributed to the unique urchin-like structure and the synergy between Ni and Fe species, which can not only provide more active sites and accelerate electron transfer, but also promote electrolyte transport and gas emission.

Ginsenosides are the main active compounds of ginseng, American ginseng and Panax notoginseng. They have certain pharmacological effects on the cardiovascular, immune and central nervous systems. Most ginsenosides are naturally classified as protopanaxatriol (PPT), protopanaxadiol (PPD), and oleanolic acid (OA) according to their aglycone skeletons. The nine main ginsenosides are Rb1, Rb2, Rb3, Rc, Rd, Re, Rf, Rg1 and Rg2. Accurate quantification of ginsenosides is imperative because they are the characteristic components and quality evaluation indicators of health foods. A new method based on solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) was developed for the determination of the nine ginsenosides in health foods. First, the pretreatment conditions were optimized. With the aim of purifying the samples and removing impurities, SPE cartridges with different packing materials, such as Alumina-N/XAD-2 SPE Cartridge, C18 and HLB were investigated. Based on the purification efficiencies, recoveries and other factors, the Alumina-N/XAD-2 SPE cartridge composite SPE column was selected as the pretreatment purification column. The eluents were then optimized. When water was used as the eluent, the ginsenosides could remain adsorbed on the SPE column, and could not be eluted down with other water-soluble substances. By increasing the proportion of ethanol in the eluent, the ginsenoside adsorbed on the filler of the SPE column could be gradually eluted. When the proportion of ethanol in the eluent reached 70%, the ginsenosides could be completely eluted. The effects of different volumes of 70% ethanol elution solvent (5-30 mL) on the extraction efficiencies of ginsenosides were also investigated. The results showed that when the volume of the elution solvent reached 20 mL, the ginsenosides were completely eluted. Then, the chromatographic conditions and MS parameters were optimized. By examining the ionization cracking of ginsenosides, the quasi-molecular ions and corresponding fragment ions in ginsenoside primary MS were determined. After optimizing the chromatographic conditions and MS parameters, not only the sensitivity of the method was improved, but also the isomers Rb2, Rb3 and Rc with the same quasi-molecular ions and the corresponding fragment ions were completely separated. Good separation was achieved for the nine ginsenosides, thus meeting the requirements for accurate quantification. Finally, chromatographic separation was achieved on a Hypersil Gold C18 column (100 mm×2.1 mm, 1.9 μm) under linear gradient elution using a 5 mmol/L ammonium acetate solution (with 0.1% formic acid) and acetonitrile as the mobile phases. The nine ginsenosides were detected using a triple quadrupole MS detector under ESI - and multiple reaction monitoring (MRM) modes, and quantified by the external standard method. The nine ginsenosides showed a strong positive linear correlation (r2>0.9950) in the range of 0.005-0.5 μg/mL. The sample recoveries and the corresponding relative standard deviations (RSDs) were 81.1%-114.2% and 0.4%-8.0% (n=6), respectively. Eleven batches of health foods on the market, among which six batches contained ginseng, American ginseng or Panax notoginseng ingredients, were analyzed by the developed method, and the ginsenosides were detected. The total ginsenosides contents were close to those mentioned on the label. However, the nine ginsenosides were detected in one batch of health food, whose label did not indicated ginseng, American ginseng or Panax notoginseng. The nine ginsenosides were not detected in the remaining batches of health foods.The health food extract was directly loaded and purified without any complex pretreatment. The UPLC⁃MS/MS method, not only helped shorten the analysis time, but also accurate quantification of low ginsenoside contents in complex matrix samples. The developed method is simple and rapid, with high throughput, thus being suitable for the quantitative analysis of the nine ginsenosides in health foods.

The electrocatalytic oxygen evolution reaction (OER) is the bottleneck to overall water splitting because of the slow kinetics of the four-electron transfer process. Therefore, it is of great significance to develop OER electrocatalysts with high activity, long durability, and scalability. Herein, we present a selenium-coated cobalt selenide (CoSe2@Se) catalyst that was first synthesized by in-situ growth on carbon cloth (CC) surface by hydrothermal method, followed by soaking treatment to prepare a three-dimensional coral-like Fe2O3-CoSe2@Se/CC composite. Electrochemical studies revealed that the optimized Fe2O3-CoSe2@Se/CC catalyst only requires 250 mV to reach 10 mA cm−2 current density, yields a small Tafel slope (50.2 mV dec−1), and has good stability (10 mA cm−2@70 h) in the electrocatalytic OER process. The overall water splitting using Fe2O3-CoSe2@Se/CC as anode only requires 1.58 and 1.69 V to achieve 10 and 100 mA cm−2, respectively, much better than most previously reported catalysts. Analysis showed that the three-dimensional coral-like morphology exposing more active sites and the synergy between different species (giving rise to, inter alia, a favorable electronic structure that lowers the electrode overpotential) are the key to the observed improved electrocatalytic performance. This work provides a novel strategy for the rational design of nanostructured OER hybrid catalysts in the future.

The mutual dependence of businesses and society has emphasized the growing importance of the concept of corporate social responsibility (CSR). Despite the fact that CSR has emerged as one of the leading management concerns worldwide, both businesses and academia have largely ignored its application in developing countries. Many studies have shown that CSR has a positive impact on consumers' loyalty and purchase intention. This study will introduce trust as an intermediary variable to explore the impact of the four dimensions of CSR, including society, environment, economy and law, on consumer loyalty and purchase intention, and further explore whether the loyalty and purchase intention will lead to consumers' actual purchase behavior. In addition, product types of green products are introduced as moderating variables to further explore the impact of social responsibility on consumers' actual green product purchases.

E-commerce retailers and traditional retailers implement a new retail model of “online and offline” integration, which is the main direction for the future development and reform of the retail industry. In response to the complex and changing market demand, more and more retailers are beginning to transform into dual-channel retailers. However, in the process of transformation, the following problems will be encountered: how to set the price of products for online channels and offline channels; consumers' acceptance of online channels. In view of the above problems, this paper considers factors such as the degree of consumer acceptance of online channels and the cost of purchasing by consumers. This article studies the competitive situation of different types of retailers in the market, and makes a comparative analysis of the competitive equilibrium of unified pricing and differential pricing strategy when different types of retailers open dual channels. We got three discoveries. First, in the fierce market competition, dual-channel retailers have more competitive advantages than single-channel retailers. Second, for traditional retailers, they can gain more profits and competitive advantages by adopting differential pricing or uniform pricing strategy compared with before the transformation. Finally, the rational choice of e-commerce retailers is to use differential pricing in the transition process, or not to transform to ensure price advantage.

With the rapid development of e-commerce, online comments has become an important reference for consumers when choosing, purchasing products or services. This paper takes the number, quality, form, timeliness and credibility of the comment as the starting point, adopts the questionnaire survey method, takes the college students as the main research object, and uses the factor analysis and regression analysis methods to study the differences in the impact of positive and negative comments on consumer perceived usefulness who purchase electronic digital products online. This study found that the impact of different types of comments on consumer perceived usefulness is quite different. Different commentary factors have different effects on consumer perceived usefulness, and corresponding countermeasures and suggestions are proposed.