Thermally Reduced Graphene Oxide Membranes Revealed Selective Adsorption of Gold Ions from Mixed Ionic Solutions.

The recovery of gold from water is an important research area. Recent reports have highlighted the ultrahigh capacity and selective extraction of gold from electronic waste using reduced graphene oxide (rGO). Here, we made a further attempt with the thermal rGO membranes and found that the thermal rGO membranes also had a similarly high adsorption efficiency (1.79 g gold per gram of rGO membranes at 1000 ppm). Furthermore, we paid special attention to the detailed selectivity between Au3+ and other ions by rGO membranes. The maximum adsorption capacity for Au3+ ions was about 16 times that of Cu2+ ions and 10 times that of Fe3+ ions in a mixture solution with equal proportions of Au3+/Cu2+ and Au3+/Fe3+. In a mixed-ion solution containing Au3+:Cu2+:Na+:Fe3+:Mg2+ of printed circuit board (PCB), the mass of Au3+:Cu2+:Na+:Fe3+:Mg2+ in rGO membranes is four orders of magnitude higher than the initial mass ratio. A theoretical analysis indicates that this selectivity may be attributed to the difference in the adsorption energy between the metal ions and the rGO membrane. The results are conducive to the usage of rGO membranes as adsorbents for Au capture from secondary metal resources in the industrial sector.

High-Efficiency Ion Enrichment inside Ultra-Short Carbon Nanotubes.

The ion-enrichment inside carbon nanotubes (CNTs) offers the possibility of applications in water purification, ion batteries, memory devices, supercapacitors, field emission and functional hybrid nanostructures. However, the low filling capacity of CNTs in salt solutions due to end caps and blockages remains a barrier to the practical use of such applications. In this study, we fabricated ultra-short CNTs that were free from end caps and blockages using ball milling and acid pickling. We then compared their ion-enrichment capacity with that of long CNTs. The results showed that the ion-enrichment capacity of ultra-short CNTs was much higher than that of long CNTs. Furthermore, a broad range of ions could be enriched in the ultra-short CNTs including alkali-metal ions (e.g., K+), alkaline-earth-metal ions (e.g., Ca2+) and heavy-metal ions (e.g., Pb2+). The ultra-short CNTs were much more unobstructed than the raw long CNTs, which was due to the increased orifice number per unit mass of CNTs and the decreased difficulty in removing the blockages in the middle section inside the CNTs. Under the hydrated-cation-π interactions, the ultra-short CNTs with few end caps and blockages could highly efficiently enrich ions.

High-performance polarization-sensitive photodetectors on two-dimensional ß-InSe.

Two-dimensional (2D) indium selenide (InSe) has been widely studied for application in transistors and photodetectors, which benefit from its excellent optoelectronic properties. Among the three specific polytypes (γ-, ϵ- and ß-phase) of InSe, only the crystal lattice of InSe in ß-phase (ß-InSe) belongs to a non-symmetry point group of [Formula: see text], which indicates stronger anisotropic transport behavior and potential in the polarized photodetection of ß-InSe-based optoelectronic devices. Therefore, we prepare the stable p-type 2D-layered ß-InSe via temperature gradient method. The anisotropic Raman, transport and photoresponse properties of ß-InSe have been experimentally and theoretically proven, showing that the ß-InSe-based device has a ratio of 3.76 for the maximum to minimum dark current at two orthogonal orientations and a high photocurrent anisotropic ratio of 0.70 at 1 V bias voltage, respectively. The appealing anisotropic properties demonstrated in this work clearly identify ß-InSe as a competitive candidate for filter-free polarization-sensitive photodetectors.

Exploring the physical origin of the electrocatalytic performance of an amorphous alloy catalyst via machine learning accelerated DFT study.

The amorphous alloy Pd40Ni10Cu30P20 is a rising star as an HER catalyst since it possesses an excellent electrocatalytic activity and a high durability in practical experiments. However, the physical origin of the electrocatalytic performance of the amorphous alloy catalyst is still unclear due to the difficulty of amorphous modelling and the huge cost of DFT calculations. Here, we built a Smooth Overlap of Atomic Positions-Machine Learning (SOAP-ML) model to accelerate the DFT study on the effect of the local atomic environment of the Pd40Ni10Cu30P20 catalyst. Compared to pure DFT-calculated results and experiment, our model makes a good prediction (MSE = 0.018) of the local atomic environment with the best catalysis. We calculated 40 000 active sites on the amorphous alloy surface and obtained the optimal atomic ratio of the alloy catalyst (Pd : Cu : P : Ni = 0.51 : 0.33 : 0.09 : 0.07), indicating that the Pd d electrons mainly enhance the catalytic performance. We employed the SOAP-ML model to reveal the physical origin of the long durability as the dealloying of Ni, which is highly consistent with the experimental results. The above results all prove the high accuracy and reliability of the established SOAP-ML model and provide an appealing idea for the future application of the amorphous alloy.

Sociodemographic Differences in Intimate Partner Violence Prevalence, Chronicity, and Severity Among Young Sexual and Gender Minorities Assigned Male at Birth: The P18 Cohort Study.

Intimate partner violence (IPV) is prevalent among young sexual and gender minorities assigned male at birth (YSGM-AMAB). However, few studies have examined the chronicity or distinguished between minor and severe forms of IPV among YSGM-AMAB. Furthermore, while past research has documented differences in IPV by race/ethnicity, sexual identity, gender identity, income, and education in other populations, few studies have examined these sociodemographic characteristics in relation to IPV in YSGM-AMAB. Thus, the present study aims to: (1) estimate past year prevalence and chronicity of minor and severe forms of IPV victimization and perpetration in a diverse sample of (N = 665) YSGM-AMAB in New York City, and (2) examine differences in IPV prevalence and chronicity by the aforementioned sociodemographic characteristics. Cross-sectional data from [BLINDED] informed these descriptive and inferential analyses. Nearly half of all participants reported past year IPV victimization and approximately 40% reported perpetration. Psychological violence was the most common form of victimization, followed by sexual, physical, and injury victimization. Psychological violence was the most common form of perpetration, followed by physical, sexual, and injury perpetration. Regarding sociodemographic differences in last year IPV prevalence, bisexual, transgender, and lower income YSGM-AMAB were more likely to report several subtypes of IPV victimization. Whereas Asian/API, bisexual, transgender, and lower income participants were more likely to report several subtypes of IPV perpetration. Regarding last year IPV chronicity, non-graduate YSGM-AMAB reported more instances of two subtypes of IPV victimization, while Black, White, cisgender, upper income, non-graduate participants reported more instances of several subtypes of IPV perpetration. These findings may be used to develop IPV prevention and intervention programs, inform future research endeavors, and develop and strengthen policies that reduce sociodemographic inequalities and promote more favorable sociopolitical conditions for YSGM-AMAB.

Monolayer InSe photodetector with strong anisotropy and surface-bound excitons.

The in-plane anisotropy of monolayer InSe plays a critical role in the application of photodetectors. In this work, through nonequilibrium Green's function density functional theory (NEGF-DFT) and time-dependent density functional theory (TD-DFT) calculations, we investigated the anisotropic quantum transport in darkness and under linearly polarized light, and explored the role of surface-bound excitons in the anisotropic photocurrent. The anisotropic dark quantum transport is attributed to different potential barriers in the zigzag and armchair orientations (Id-zig/Id-arm = 1.2 × 102). Linearly polarized photocurrent calculations show that the extinction ratio reaches a maximum value of 105.67. Moreover, surface-bound exciton calculations via TD-DFT revealed that the strong anisotropic photocurrent derives from surface-bound excitons generated in the In 5pz, Se 4pz, and Se 4dz2 orbitals. InSe shows tremendous potential for use in field-effect transistors, flexible nano- and optoelectronics, and polarized light devices.

Physically Compatible Machine Learning Study on the Pt-Ni Nanoclusters.

Pt-Ni alloy nanoclusters are essential for high-performance catalysis, and the full description for the finite temperature properties is highly desired. Here we developed an efficient machine learning method to evaluate the accurate structure-stability correspondence in a Pt(85-x)-Nix nanocluster over the structural space with a dimension of 3.84 × 1025. On the basis of the physical model and big-data analysis, for the first time, we demonstrated that the segregation-extent bond order parameter (BOP) and the shell-resolved undercoordination ratio play the key roles in the structural stability. This a priori knowledge extremely reduced the computational costs and enhanced the accuracies. With the 500-sample train data set generated by density functional theory (DFT)-level geometry optimizations, we fit the machine-learning excess energy potential and verified the mean-square-error is <0.13. Our physically niche genetic-machine learning program (PNG-ML) searched 2.5 × 105 structures and predicted precisely the most stable Pt43-Ni42 (x = 42). The structural space dimension was reduced by 1020 fold using our PNG-ML method. The Pt/Ni ratio of the most stable nanocluster is 1.02, which is highly consistent with the experimental observation of 1.0. The above results provide reliable theoretical references for the realistic applications of Pt-Ni nanoclusters and suggest feature engineering for future studies on binary alloys nanostructures.

Unexpected Solute Occupancy and Anisotropic Polarizability in Lewis Basic Solutions.

Density functional computation revealed that in YOH solvation (Y = Li, Na, and K), the Y+ cation locates eccentrically at the interstitial hollow site to form the Y+·4H2O unit, and the hydroxyl adds an excessive electron lone pair ":" to form a OH-·H2O unit where the hydroxide stays in the the center. The surrounding four oriented H2O neighbors interact with the Y+ through Y+ ↔ H+ repulsion and Y+:O2- attraction, causing the Y+ eccentric dislocation by some 0.80 Å. The ":" turns one O:H-O bond into the O: ⇔ :O super hydrogen bond by altering H2O·4H2O into HO-·4H2O. The repulsive Y+ ↔ H+ enlarges its separation and the attractive Y+:O shortens itself, showing the anisotropic polarization of the Y+ cation. The anisotropic Y+ polarizability, O: ⇔ :O compressibility, and the H-O bond contraction of the solute OH- distorts the solute bonding network and disperses the O:H-O segmental phonon frequencies, as confirmed spectroscopically.