Rh-Cu alloy nano-dendrites with enhanced electrocatalytic ethanol oxidation activity

The application of direct ethanol fuel cell(DEFC)has been bottlenecked by the sluggish ethanol oxidation reaction(EOR).Efficient electrocatalysts for the C-C bond cleavage are essential to promote EOR with high efficiency and C1 selectivity.Here,we prepared Rh-Cu alloy nano-dendrites(RhCu NDs)with abundant surface steps through controlled co-reduction,which exhibited significantly enhanced activity and C1 selectivity(0.47 m A cm_((ECSA))^(-2),472.4 mA mg_(Rh)^(-1),and 38.9%)than Rh NDs(0.32 mA cm((ECSA))-2,322.1 mA mgRh-1,and 21.4%)and commercially available Rh/C(0.18 mA cm_((ECSA))^(-2),265.4 mA mg_(Rh)^(-1),and 14.9%).Theoretical calculations and CO-stripping experiments revealed that alloying with Cu could modulate the surface electronic structures of Rh to resist CO-poisoning while strengthening ethanol adsorption.In situ Fourier transform infrared spectroscopy(FTIR)indicated that the surface steps on RhCu NDs further promoted the C-C bond cleavage to increase the C1 selectivity.Therefore,optimizing the surface geometric and electronic structures of nanocrystals by rational composition and morphology control can provide a promising strategy for developing practical DEFC devices.

Molecular dynamics study of thermal conductivities of cubic diamond,lonsdaleite,and nanotwinned diamond via machine-learned potential

Diamond is a wide-bandgap semiconductor with a variety of crystal configurations,and has the potential applications in the field of high-frequency,radiation-hardened,and high-power devices.There are several important polytypes of diamonds,such as cubic diamond,lonsdaleite,and nanotwinned diamond(NTD).The thermal conductivities of semiconductors in high-power devices at different temperatures should be calculated.However,there has been no reports about thermal conductivities of cubic diamond and its polytypes both efficiently and accurately based on molecular dynamics(MD).Here,using interatomic potential of neural networks can provide obvious advantages.For example,comparing with the use of density functional theory(DFT),the calculation time is reduced,while maintaining high accuracy in predicting the thermal conductivities of the above-mentioned three diamond polytypes.Based on the neuroevolution potential(NEP),the thermal conductivities of cubic diamond,lonsdaleite,and NTD at 300 K are respectively 2507.3 W·m^(-1)·K^(-1),1557.2 W·m^(-1)·K^(-1),and 985.6 W·m^(-1)·K^(-1),which are higher than the calculation results based on Tersoff-1989 potential(1508 W·m^(-1)·K^(-1),1178 W·m^(-1)·K^(-1),and 794 W·m^(-1)·K^(-1),respectively).The thermal conductivities of cubic diamond and lonsdaleite,obtained by using the NEP,are closer to the experimental data or DFT data than those from Tersoff-potential.The molecular dynamics simulations are performed by using NEP to calculate the phonon dispersions,in order to explain the possible reasons for discrepancies among the cubic diamond,lonsdaleite,and NTD.In this work,we propose a scheme to predict the thermal conductivity of cubic diamond,lonsdaleite,and NTD precisely and efficiently,and explain the differences in thermal conductivity among cubic diamond,lonsdaleite,and NTD.

Peliosis hepatis complicated by portal hypertension following renal transplantation

Peliosis hepatis(PH)is a vascular lesion of the liver that mimics a hepatic tumor.PH is often associated with underlying conditions,such as chronic infection and tumor malignancies,or with the use of anabolic steroids,immunosuppressive drugs,and oral contraceptives.Most patients with PH are asymptomatic,but some present with abdominal distension and pain.In some cases,PH may induce intraperitoneal hemorrhage and portal hypertension.This study analyzed a 46-year-old male who received a transplanted kidney nine years prior and had undergone long-term immunosuppressive therapy following the renal transplantation.The patient experienced progressive abdominal distention and pain in the six months prior to this study.Initially,imaging studies revealed multiple liver tumor-like abnormalities,which were determined to be PH by pathological analysis.Because the hepatic lesions were progressively enlarged,the patient suffered from complications related to portal hypertension,such as intense ascites and esophageal varices bleeding.Although the patient was scheduled to undergo liver transplantation,he suffered hepatic failure and died prior to availability of a donor organ.

Multi-twinned gold nanoparticles with tensile surface steps for efficient electrocatalytic CO_(2) reduction

CO_(2) reduction reactions(CO_(2)RR) powered by renewable electricity can directly convert CO_(2) to hydrocarbons and fix the intermittent sustainable energy in portable chemical fuels. It is of great importance to develop advanced catalysts that can boost CO_(2)RR with high activity, selectivity, and efficiency at low overpotentials. Here, we report the solution synthesis using H_(2)O_(2) to modify the surface structures of gold multi-twinned nanoparticles(AuMPs) and create tensile surface steps. Calculations predicted significantly enhanced CO_(2) adsorption and boosted CO_(2)RR capabilities with inhibited hydrogen evolution reaction activity for the tensile surface steps with modified electronic structure. The H_(2)O_(2)-treated AuMPs with surface steps and 3.83% tensile lattices showed much higher activity and selectivity at lower overpotentials for CO_(2)RR than pristine gold nanoparticles.The CO-production current density reached about 98 mA cm^(-2) with a Faradaic efficiency of 95.7% at -0.30 V versus reversible hydrogen electrode in the flow cell, showing a half-cell energy efficiency as high as ~83%. Our strategy represents a rational catalyst design by engineering the surface structures of metal nanoparticles and may find more applicability in future electrocatalysis.