Modeling Monte Carlo simulation on photon regeneration effects of perovskite FAPbI3 for photovoltaic applications.

Controlling the photon regeneration effects in FAPbI3 films is a noteworthy approach to improve the photovoltaic (PV) efficiency of FAPbI3-based solar cells. However, the lack of systematic study on the relationship between photon regeneration effects and PV efficiency in the experimental process makes it difficult to control the photon regeneration effects effectively. In this work, we combine the Monte Carlo sampling method and the polar coordinate calculation method to design a new algorithm for a detailed simulation of the main processes of photon regeneration effects affecting the PV efficiency in a model based on an n-i-p type FAPbI3 perovskite solar cell (PSC). The algorithm is validated to be used to compare the power-conversion efficiency (PCE) of different PSCs to filter out the PSC structure with the highest PCE or to determine the range of material parameter values corresponding to the highest PCE. This work opens up new ideas to effectively control the photon regeneration effects in PSCs to improve the device PV efficiency.

Construction of an ultra-sensitive electrochemical sensor based on polyoxometalates decorated with CNTs and AuCo nanoparticles for the voltammetric simultaneous determination of dopamine and uric acid.

A composite modified electrode was prepared based on α-K7P2VW17O62·18H2O (P2W17V), CNTs and AuCo nanoparticles (AuCo NPs), and used as a structurally stable and highly sensitive electrochemical sensor for simultaneous determination of dopamine (DA) and uric acid (UA). The combination of three active components endows the electrode with large specific surface area, high electrical conductivity, and excellent electrochemical activity. The as-prepared modified electrode exhibited impressive electrocatalytic oxidation performance of DA and UA at an optimum working potential (0.172 V vs. Ag/AgCl for DA and 0.288 V vs. Ag/AgCl for UA) with linear detection range from 1.25 × 10-6 to 2.81 × 10-4 M and 0.75 × 10-6 to 1.66 × 10-4 M and the detection limit of 0.15 and 0.25 µM (S/N = 3) for DA and UA, respectively. Additionally, the peak-to-peak separation signals in DPV are 116 mV. The influence of several possible co-existing substances was investigated. The applicability of the method for real samples analysis was tested by determination of DA and UA in human serums. This new sensor holds great promise for sensitive determination of DA and UA in real application. Graphical abstract.

Molten salt/liquid metal extraction: Electrochemical behaviors and thermodynamics properties of La, Pr, U and separation factors of La/U and Pr/U couples in liquid gallium cathode.

The electrochemical behavior of lanthanides (La, Pr) and actinide (U) on inert W and liquid Ga electrodes in LiCl-KCl molten salt as well as their related thermodynamic properties were experimentally determined for further Lns/Ans separation. The results indicate that the reductions of La3+ and Pr3+ in LiCl-KCl melts are both one-step process with three electrons exchanged, and the reactions are quasi-reversible processes at low scan rate. Temperature dependencies of apparent standard redox potentials of La(Ga), Pr(Ga) and U(Ga) alloys were determined by open-circuit chronopotentiometry versus Cl-/Cl2 reference electrode. The activity and activity coefficients of lanthanum, praseodymium and uranium on the liquid Ga electrode in the temperature interval 723-813 K were calculated. The separation factors for La/U and Pr/U on the liquid Ga electrode in the molten salt were determined by logθU/La=-10.39+11440.69T±0.0125 and logθU/Pr=-5.84+7763.27T±0.07. The separation factors of La/U and Pr/U on the liquid Ga electrode indicate that lower temperature should be more effective for separating uranium.

Water-locking molecule-assisted fabrication of nature-inspired Mg(OH)2 for highly efficient and economical uranium capture.

With the depletion of uranium terrestrial deposits, researchers have focused on the development of adsorbents to extract radioactive uranium from seawater/wastewater. However, the artificial manipulation of adsorbents for the cost-effective extraction of radioactive uranium from large numbers of water samples is still significantly challenging. Herein, a facile yet versatile stepwise strategy has been reported for the fabrication of adsorbents. Magnesium hydroxide (Mg(OH)2) was fabricated via the in situ conversion of a natural ore powder (magnesite), whose unique internal pore structure is highly suitable for the development of highly efficient sorbents. The coordination interaction of the synthesized adsorbent with uranium was enhanced by further introducing inexpensive molecules with water-locking properties, which resulted in superior extraction capacity and low production cost. After careful calculation, the cost per kilogram of the adsorbent was found to be about $0.21. The adsorption behaviors of the synthesized adsorbent CMC-PAM/Mg(OH)2 were investigated by batch adsorption, flow-through column adsorption (in laboratory), and field adsorption experiments in natural seawater and river. Representatively, CMC-PAM/Mg(OH)2 was exceptional in extracting uranium not only at high concentrations with sufficient capacities in a wide pH range (1584.67 mg g-1 and 454.55 mg g-1 at pH = 5 and pH = 8, respectively), but also in trace quantities including uranium in a flow-through column (55.68 mg g-1), natural seawater (8.6 mg g-1), and river (6.7 mg g-1). Inspired by this excellent performance, the effects of competitive ions on the selective adsorption of uranium by CMC-PAM/Mg(OH)2 in simulated wastewater and seawater environments were further studied. Using a combination of FTIR spectroscopic and XPS studies, it was revealed that the amine and hydroxyl groups enhanced the overall uranyl affinity of the CMC-PAM/Mg(OH)2 composite.