Compared with the monometallic phosphides, bimetallic phosphides can further improve the catalytic performance for hydrogen evolution reaction (HER). As such, the rational design and facile synthesis of bimetallicbased phosphides with well-controlled architectures and compositions is of scientific and technological importance. In this work, Fe−Co Prussian blue analogue (PBA) nanocones (NCs) have been successfully fabricated via an intercalation reaction strategy by utilizing layer structured α-Co(OH) 2 NCs as self-sacrificing templates. After calcination and phosphorization process, Fe−Co PBA NCs can be converted to Fe-doped Co x P NCs without obvious shrinkage. Electrochemical tests show that Fe incorporation can effectively promote the electrocatalytic activities of Co x P. This simple and effective method will be of benefit for the development of other functional Co-based bimetallic compounds. Furthermore, this strategy can possibly be extended to fabricate a series of PBA materials with special structure and novel morphology, which can serve as a promising platform for diverse applications, especially in energy storage and conversion.
High‐performance electrocatalysts with superior stability are critically important for their practical applications in the hydrogen evolution reaction (HER). Recently, some electrocatalysts with hollow and porous structures have attracted much attention because of their large surface‐to‐volume ratio and highly exposed active edge sites. In this study, the hierarchical Fe‐based glycolate hollow microspheres composed of nanosheet subunits are synthesized by the solvothermal method. The morphology and microstructure of Fe‐based glycolate hollow microspheres can be controlled by adjusting the amount of ethylenediamine. After phosphorizing in nitrogen, the Fe‐based glycolate can be converted into FeP with well‐retained structure. Furthermore, the hierarchical FeP hollow microspheres have been used as electrocatalysts for HER. Benefitting from its high surface area, the FeP hollow microspheres exhibited high catalytic activity toward HER with low onset overpotential, small Tafel slope, and good stability under acidic conditions. The excellent catalytic activity and long‐term stability suggest promising application potential of FeP hollow microspheres in electrocatalytic hydrogen evolution.
Summary
Lithium‐sulfur batteries are considered the most promising candidates for energy storage materials in the future, but the shuttle of polysulfides has seriously affected the development of lithium‐sulfur batteries. Because the surface morphology of the material determines its structural properties to some extent. Therefore, the surface of celgard‐2400 is structurally modified by controlling the polymerization of dopamine to further improve the performance of the separator. Utilizing the effective adsorption performance of dopamine and the interaction with PEI, an effective network structure is formed. The polydopamine and polyethyleneimine (PDA/PEI) coating forms a good physical barrier while a large amount of N, O elements and polysulfides adsorb each other, which effectively inhibits the shuttle of polysulfides. After coating, the rapid increase of the electrolyte wettability and liquid absorption rate of the separator will provide a guarantee for lithium ion transmission. Through electrochemical tests, the initial capacity of the battery modified by PDA/PEI coating reached 1250 mAh g−1 at 0.2 C, and remained above 900 mAh g−1 after 100 cycles. While the rate performance and cycle stability are improved, the electrochemical impedance is also reduced. This solution can be prepared lot size is a promising improved technology.
In this article, we investigated changes in public firms’ attitudes towards environmental protection in 2018–2021 in China. We crawled the firm–investor Q&A record on the website of East Money, extracted the carbon- and environment-related corpus, and then applied the sentiment analysis method of NLP (natural language processing) to calculate the sentiment weight of each firm-level record to estimate the attitude before and after towards carbon reduction. We found that there were significant changes in firms’ attitudes towards carbon reduction and environmental protection after the COVID-19 pandemic and the implementation of environment-related policies. We also found a heterogeneous effect of the attitude in different industries. In addition, we built several models to examine the relationship between a firm’s carbon reduction attitude and its financial performance. We found that: A goal with consequent specific policies can raise the positive attitudes of firms toward carbon reduction topics; firms’ attitudes toward ecological topics are different from industry to industry, which means that there are different needs and situations in the trend of carbon reduction from industry to industry. COVID-19 influenced firms’ attitudes toward carbon reduction and environmental protection, calling back the classic dilemma or trilemma of economic growth, carbon reduction, and energy consumption or, perhaps, epidemic control today. The stock situation also influenced the attitude toward environmental protection.
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