The current focus of research lies in the advancement of electrocatalysts based on phosphides, which exhibit exceptional features and robust stability in alkaline environments.
Heterojunction photocatalysts for environmental pollutant removal have attracted great attention because of their excellent photocatalytic efficiency. In this study, we report a novel Ba5Ta4O15/AgVO3 heterojunction photocatalyst with excellent photocatalytic activity, which was synthesized by a facile, two-step, self-assembly strategy. Transmission electron microscopy (TEM) reveals that Ba5Ta4O15 nanosheets adhered to the surface of AgVO3 nanoribbons to form Ba5Ta4O15/AgVO3 heterojunctions. The as-obtained photocatalysts exhibited enhanced photocatalytic activities for Acid Red G (ARG) degradation, which are almost 2.7 times higher than that of AgVO3. The trapping experiments, electrochemical and electron paramagnetic resonance analyses altogether indicate that the enhanced photocatalytic performance could be attributed to the synergy effect of the hole dominated charge transform path and localized surface plasmon resonance (LSPR). Finally, a possible photocatalytic mechanism of the photocatalytic progress was discussed. This study might provide a novel strategy toward designing highly efficient heterojunction photocatalyst systems for pollutant degradation and environmental remediation.
The Automatic Identification System (AIS) is an automatic tracking system which has been widely applied in the fields of intelligent transportation systems, e.g., collision avoidance, navigation, maritime supervision and management. Compare with other positioning systems, e.g., very high frequency (VHF) and radar, AIS can conquer the human errors and it is almost not affected by the external environment. To make better use of the AIS data, it is necessary to statistically analyze the massive AIS trajectories. The statistical results could make us better understand the potential properties of AIS trajectories. It is well known that most current practical applications are strongly dependent on the geometrical structures of AIS trajectories. In this paper, a Gaussian Mixture Model (GMM) is introduced to investigate the longitude and latitude differences of AIS trajectory data. The parameters of GMM are estimated using the Expectation Maximization (EM) algorithm. The experimental results have illustrated the superior performance of our proposed method.
Surface charge localization and inferior charge transfer efficiency seriously restrict the supply of reactive hydrogen and the reaction dynamics of CO2 photoreduction performance of photocatalysts. Herein, chemically bonded BiVO4/Bi19Cl3S27 (BVO/BCS) S-scheme heterojunction with a strong internal electric field is designed. Experimental and density function theory calculation results confirm that the elaborated heterojunction accelerates the vectorial migration of photogenerated charges from BiVO4 to Bi19Cl3S27 via the interfacial chemical bonding interactions (i.e., Bi-O and Bi-S bonds) between Bi atoms of BVO and S atoms of BCS or Bi atoms of BCS and O atoms of BVO under light irradiation, breaking the interfacial barrier and surface charge localization of Bi19Cl3S27, and further decreasing the energy of reactive hydrogen generation, CO2 absorption and activation. The separation efficiency of photogenerated carriers is much more efficient that counterpart individual in BVO/BCS S-scheme heterojunction system. As a result, BVO/BCS heterojunction exhibits a significantly improved continuous photocatalytic performance for CO2 reduction and the 24 h CO yield reaches 678.27 μmol·g−1. This work provides an atomic-level insight into charge transfer kinetics and CO2 reduction mechanism in S-scheme heterojunction.
Abstract The rational design of an S‐scheme heterojunctions in hybrid semiconductors to realize separated charge carriers and sufficient redox ability is considered as an attractive way to achieve high photocatalytic activity in diluted CO 2 reduction (DCR). An S‐scheme heterojunction formed in the fibrous Ta 2 O 5 /Ag 2 S nanostructures is proposed for improving the photocatalytic performance in DCR under simulated solar irradiation. Benchmark CH 4 production rates of 132.3 µmol g −1 are obtained with 93.1% selectivity over optimal catalyst ASTO‐2. The remarkable activity in photocatalytic DCR of Ta 2 O 5 /Ag 2 S is attributed to the unique 0D/1D structure and effective charge separation by the photoinduced strong internal electric field and S‐scheme mechanism. The measurements of in situ X‐ray photoelectron spectroscopy, femtosecond transient absorption spectroscopy, and electron paramagnetic resonance further confirm the photoinduced carrier transfer pathways following the S‐scheme mechanism. This research can provide a new strategy for designing the S‐scheme heterojunctions to improve the photocatalytic performance of diluted CO 2 conversion.
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