Regional Discrimination in P2P Lending of China

Through empirical analysis of individual micro data from one peer-to-peer lending platform, this paper aims to expand the research on regional discrimination in China\u27s P2P lending market from a new perspective. Descriptive statistics of orders and difference test of success rate show that, for cities of different grades, there is a huge difference in the success rate. The main empirical finding is that under the control of other factors, city grade has a significant positive effect on loan success rate, namely the success rate of cities developing better is higher, revealing the existence of regional discrimination. Further study find the default rate of less developed cities, whose success rate is lower, is relatively higher, which proves the regional discrimination here is a rational statistical discrimination

Beneficial synergy of adsorption-intercalation-conversion mechanisms in Nb₂O₅@nitrogen-doped carbon frameworks for promoted removal of metal ionsviahybrid capacitive deionization

Capacitive deionization (CDI) is an emerging water purification technology, but the ion adsorption capacity of traditional carbon-based CDI electrodes is still unsatisfactory. Herein, a novel faradaic electrode by anchoring Nb2O5nanoparticles on nitrogen-doped carbon frameworks as anodes and activated carbon (AC) as cathodes in a hybrid capacitive deionization (HCDI) system was originally developed to capture Na+ionsviaadsorption-intercalation-conversion mechanisms. The synergistic effects of the nanostructure and carbon coating were beneficial to enhancing electrical conductivity and offering fast Na+ion diffusion pathways. Impressively, the HCDI system demonstrated an excellent ion adsorption capacity of 35.4 mg g−1in a 500 mg L−1NaCl solution at 1.2 V as well as stable regeneration ability.In situRaman andex situXPS measurements unraveled that the mechanism of ion removal from water was the reversible redox reaction of Nb2O5. The new overall understanding of the synergistic effects opens opportunities for the design of HCDI systems for efficient removal of metal ions from saline water.</p

Capacitive Deionization of Saline Water by Using MoS₂-Graphene Hybrid Electrodes with High Volumetric Adsorption Capacity

Capacitive deionization (CDI) has received wide attention as an emerging water treatment technology because of its low energy consumption, low cost, and high efficiency. However, the conventional carbon electrode materials for CDI have low densities, which occupy large volumes and are disadvantageous for use in limited space (e.g., in household or on offshore platforms). In order to miniaturize the CDI device, it is quite urgent to develop high volumetric adsorption capacity (VAC) electrode materials. To overcome this issue, we rationally designed and originally developed high VAC MoS2-graphene hybrid electrodes for CDI. It is interesting that MoS2-graphene hybrid electrode has a much higher NaCl VAC of 14.3 mg/cm3 with a gravimetric adsorption capacity of 19.4 mg/g. It has been demonstrated that the adsorption capacity is significantly enhanced because of the rapid ion transport of MoS2 and high electrical conductivity of graphene. In situ Raman spectra and high-angle annular dark-field scanning transmission electron microscopy tests demonstrated a favorable Faradaic reaction, which was crucial to enhancing the NaCl VAC of the MoS2-graphene hybrid electrode. This work opens a new avenue for miniaturizing future CDI devices.</p

Enhanced capacitive deionization of saline water using N-doped rod-like porous carbon derived from dual-ligand metal-organic frameworks

Capacitive deionization (CDI) removes ions from brine, and is forward-looking technology due to its low energy consumption, low cost and prevention of secondary pollution. Removal capacity is still an issue for CDI technology. It is quite urgent to design a high-performance CDI electrode material with a reasonable porous structure, excellent conductivity and hydrophilic surface. Herein, we originally designed nitrogen-doped rod-like porous carbon derived from dual-ligand metal-organic frameworks (MOFs), in which two ligands, namely 1,4-benzenedicarbocylic acid and triethylenediamine, coordinate with zinc (Zn). 1,4-Benzenedicarbocylic acid can be used as a pore-forming agent to increase the specific surface area of the carbon material, and triethylenediamine is used as a nitrogen doping source to increase the hydrophilicity and conductivity of the carbon material. By adjusting the ratio of the two ligands, the optimal specific surface area and nitrogen doping for the carbon material is obtained, thereby achieving the highest removal capacity for capacitive deionization of brine. The obtained carbon materials possess a hierarchical porous structure with moderate nitrogen doping. The large specific surface area of the electrode materials delivers many adsorption sites for adsorption of salt ions. The hierarchically porous structure provides rapid transport channels for salt ions, and high-level N doping enhances the conductivity and hydrophilicity of the carbon materials to some extent. More importantly, the salt removal capacity of the electrodes is as high as 24.17 mg g-1 at 1.2 V in 500 mg L-1 NaCl aqueous solution. Hence, the moderate nitrogen-doping porous carbon material derived from dual-ligand MOFs is a potential electrode material for CDI application. Such results provide a new method for the preparation of high-performance electrodes to remove ions from saline water.</p

Capacitive Deionization of Saline Water by Using MoS₂-Graphene Hybrid Electrodes with High Volumetric Adsorption Capacity

Capacitive deionization (CDI) has received wide attention as an emerging water treatment technology because of its low energy consumption, low cost, and high efficiency. However, the conventional carbon electrode materials for CDI have low densities, which occupy large volumes and are disadvantageous for use in limited space (e.g., in household or on offshore platforms). In order to miniaturize the CDI device, it is quite urgent to develop high volumetric adsorption capacity (VAC) electrode materials. To overcome this issue, we rationally designed and originally developed high VAC MoS2-graphene hybrid electrodes for CDI. It is interesting that MoS2-graphene hybrid electrode has a much higher NaCl VAC of 14.3 mg/cm3 with a gravimetric adsorption capacity of 19.4 mg/g. It has been demonstrated that the adsorption capacity is significantly enhanced because of the rapid ion transport of MoS2 and high electrical conductivity of graphene. In situ Raman spectra and high-angle annular dark-field scanning transmission electron microscopy tests demonstrated a favorable Faradaic reaction, which was crucial to enhancing the NaCl VAC of the MoS2-graphene hybrid electrode. This work opens a new avenue for miniaturizing future CDI devices.</p

Efficient removal of metal ions by capacitive deionization with straw waste derived graphitic porous carbon nanosheets

Capacitive deionization (CDI) is considered to be an energy-efficient and cost-effective technology for ion removal from saline or waste water. However, its implementation remains challenging due to low ion adsorption capacity of the commonly used electrode materials. It is thus desirable to develop highly efficient CDI electrode materials for ion removal. Herein, graphitic porous carbon nanosheets (GPCSs) were originally prepared from straw waste via a combined activation and graphitization process. Being composed of graphitic carbon sheets with abundant pores in the framework, the obtained GPCSs had a large specific surface area and good conductivity and wettability, which can provide sufficient adsorption sites and promote efficient ion transport. The GPCS electrodes presented a higher specific capacitance, good stability and low inner resistance in electrochemical tests. Moreover, the GPCSs showed a high deionization capacity of 19.3 mg g-1 at 1.2 V in a 500 mg L-1 NaCl solution. Repeated adsorption-desorption experiments demonstrated the good regeneration performance of the GPCS electrodes. Furthermore, the removal efficiency towards Cd2+, Ni2+ and Cu2+ of the GPCS electrodes is 91.5%, 97.0% and 100% at 1.2 V in a 100 mg L-1 CdCl2, NiCl2 or CuCl2 solution, respectively. This work offers a promising solution to efficient removal of ions from saline or waste water and a new route to the utilization of straw waste.</p

Intrinsic ferroelectric switching in two-dimension α\alpha-In2_2Se3_3

Two-dimensional (2D) ferroelectric semiconductors present opportunities for integrating ferroelectrics into high-density ultrathin nanoelectronics. Among the few synthesized 2D ferroelectrics, $\alpha$-In$_2$Se$_3$, known for its electrically addressable vertical polarization has attracted significant interest. However, the understanding of many fundamental characteristics of this material, such as the existence of spontaneous in-plane polarization and switching mechanisms, remains controversial, marked by conflicting experimental and theoretical results. Here, our combined experimental characterizations with piezoresponse force microscope and symmetry analysis conclusively dismiss previous claims of in-plane ferroelectricity in $\alpha$-In$_2$Se$_3$. The processes of vertical polarization switching in monolayer $\alpha$-In$_2$Se$_3$ are explored with deep-learning-assisted large-scale molecular dynamics simulations, revealing atomistic mechanisms fundamentally different from those of bulk ferroelectrics. Despite lacking in-plane effective polarization, 1D domain walls can be moved by both out-of-plane and in-plane fields, exhibiting unusual avalanche dynamics characterized by abrupt, intermittent moving patterns. The propagating velocity at various temperatures, field orientations, and strengths can be statistically described with a universal creep equation, featuring a dynamical exponent of 2 that is distinct from all known values for elastic interfaces moving in disordered media. This work rectifies a long-held misunderstanding regarding the in-plane ferroelectricity of $\alpha$-In$_2$Se$_3$, and the quantitative characterizations of domain wall velocity will hold broad implications for both the fundamental understanding and technological applications of 2D ferroelectrics.Comment: 30 pages, 6 figure

Fe-, N-Embedded Hierarchically Porous Carbon Architectures Derived from FeTe-Trapped Zeolitic Imidazolate Frameworks as Efficient Oxygen Reduction Electrocatalysts

During the design and construction of an efficient iron-nitrogen-carbon (Fe-N-C) electrocatalyst, it was difficult to avoid the formation of iron oxides along with the hierarchical carbon frameworks containing dispersed FeNx sites. As a result, a slow oxygen reduction reaction (ORR) occurred, making it difficult to improve the electrocatalytic property. Herein, we have successfully synthesized the Fe, N-doped hierarchically porous carbon architectures from FeTe-trapped ZIF-8 coated with polydopamine by heat treatment. During the pyrolysis process, the evaporation of tellurium could inhibit the formation of iron oxides, promote the formation of more FeNx active species, and facilitate the formation of mesoporous structure to accelerate mass transfer and increase the approachability of active species. The resulting Fe, N-doped porous carbon architectures possessed excellent ORR catalytic performance, and the half-wave potential was 10 mV more than that of the precious Pt/C catalysts. Besides, the obtained catalysts present a superb methanol tolerance and long-term durability compared to precious Pt/C catalysts in alkaline media. This work opens up new avenues for the construction of the uniformly dispersed FeNx sites catalysts for ORR.</p

Fe-, N-Embedded Hierarchically Porous Carbon Architectures Derived from FeTe-Trapped Zeolitic Imidazolate Frameworks as Efficient Oxygen Reduction Electrocatalysts

During the design and construction of an efficient iron-nitrogen-carbon (Fe-N-C) electrocatalyst, it was difficult to avoid the formation of iron oxides along with the hierarchical carbon frameworks containing dispersed FeNx sites. As a result, a slow oxygen reduction reaction (ORR) occurred, making it difficult to improve the electrocatalytic property. Herein, we have successfully synthesized the Fe, N-doped hierarchically porous carbon architectures from FeTe-trapped ZIF-8 coated with polydopamine by heat treatment. During the pyrolysis process, the evaporation of tellurium could inhibit the formation of iron oxides, promote the formation of more FeNx active species, and facilitate the formation of mesoporous structure to accelerate mass transfer and increase the approachability of active species. The resulting Fe, N-doped porous carbon architectures possessed excellent ORR catalytic performance, and the half-wave potential was 10 mV more than that of the precious Pt/C catalysts. Besides, the obtained catalysts present a superb methanol tolerance and long-term durability compared to precious Pt/C catalysts in alkaline media. This work opens up new avenues for the construction of the uniformly dispersed FeNx sites catalysts for ORR.</p