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The electron-rich Ru sites are isolated in body-centered cubic RuGa intermetallic compounds, which reduces the energy barrier of the rate-limiting step in the HER process, thus promoting the high-current-density HER activity.

The electrocatalytic nitrate reduction reaction (NO

The direct electrochemical nitric oxide reduction reaction (NORR) is an attractive technique for converting NO into NH3 with low power consumption under ambient conditions. Optimizing the electronic structure of the active sites can greatly improve the performance of electrocatalysts. Herein, we prepare body-centered cubic RuGa intermetallic compounds (i.e., bcc RuGa IMCs) via a substrate-anchored thermal annealing method. The electrocatalyst exhibits a remarkable NH4+ yield rate of 320.6 μmol h-1 mg-1Ru with the corresponding Faradaic efficiency of 72.3% at very low potential of -0.2 V vs. reversible hydrogen electrode (RHE) in neutral media. Theoretical calculations reveal that the electron-rich Ru atoms in bcc RuGa IMCs facilitate the adsorption and activation of *HNO intermediate. Hence, the energy barrier of the potential-determining step in NORR could be greatly reduced.

Background: Glycogen synthase kinase-3β (GSK-3β) is recently demonstrated to be a tumor promoter and a potential drug target in several tumors. However, the implication and mechanism of GSK-3β in hepatocellular carcinoma (HCC) remain unexplored. Methods: We firstly clarified the expression of GSK-3β in human HCC samples. Given that deviated retinoid signalling is critical for HCC development, we investigated where GSK-3β could be involved in the regulation. Since sorafenib is currently used to treat HCC, the involvement of GSK-3β in sorafenib treatment response was determined. Coimmunoprecipitation, GST pull down, in vitro kinase assay, luciferase reporter and chromatin immunoprecipitation were used to study the molecular mechanism. The biological readouts were examined with MTT, flow cytometry and animal experiments. Findings: We demonstrated that GSK-3β is highly expressed in HCC and associated with shorter overall survival (OS). Tumor-associated GSK-3β is correlated with reduced expression of retinoic acid receptor-β (RARβ), which is caused by GSK-3β-mediated phosphorylation and heterodimerization abrogation of retinoid X receptor (RXRα) with RARα on RARβ promoter. Overexpression of functional GSK-3β impairs retinoid response and represses sorafenib anti-HCC effect. Inactivation of GSK-3β by tideglusib can potentiate 9-cis-RA enhancement of sorafenib sensitivity (tumor inhibition: from 48.3% to 93.4%). Efficient induction of RARβ by tideglusib/9-cis-RA is required for enhanced therapeutic outcome of sorafenib, which effect is greatly inhibited by knocking down RARβ. Interpretation: Our findings suggest that overexpression of GSK-3β may confer HCC growth through interfering retinoid signalling. Targeting GSK3β can be a promising strategy for designing improved treatment of sorafenib in HCC. Funding Statement: This work is supported by grants from Natural Science Foundation of China (No. 81673467, 31471273, 31461163002/RGC N_HKU 740/14), the 10th Singapore-China Joint Research Program (S2014GR0448), Natural Science Foundation of Fujian Province (2019I0002) and Leading Talents in Scientific and Technological Innovation, Double Hundred Talents Program of Fujian Province. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: All the use of human samples and study protocols were approved by the Hospital Ethics Committee. All patients signed an informed consent form in prior to sample collection.

The study on electrochemical behavior of ammonia is a far-reaching topic, not only for its electro-oxidation elimination from effluent treatments, but also for detection of ammonia concentration by employing electrochemical sensors. Herein, we report a simple electro-chemical ammonia detector with high sensitivity/selectivity, superfast response, and long-time stability, using ultrafine Ir nanoparticles decorated 3D graphene hollow spheres. Morphological and structural analysis reveals that the inner ultrathin graphene shell effectively maximize the specific surface area and outer tiny Ir nanoparticles are optimal for offering active adsorption sites of NH3. Because of the well-defined morphology and 3D interconnected architecture, the rGO/Ir HSs modified glassy carbon electrode (GCE) exhibits superior activity for the electro-oxidation of NH3 performed in neutral medium, which is 4 times higher than that of commercial Ir/C catalyst. The amperometry technique is served to investigate the ammonia-detected performance of the rGO/Ir HSs-modified GCE, demonstrating high sensitivity and quick response from wide linear range of 0.015–75 mM (R2 = 0.998) with a detection limit of 6.5 μM. This work offers a new type of graphene-based nanohybrids to enhance the electro-oxidation and gas sensing abilities toward ammonia, leading to the development of manufacturing high-performance electro-analytical sensors.

The electro-catalytic properties can be effectively optimized by designing bimetallic alloy nanoparticles with high-content less-active metal to enhance the competence of more-active noble metal. Herein, a one-pot hydrothermal approach is demonstrated for the controllable synthesis of Ag-rich Ag9Pd1 alloy nanoactiniae with obviously enhanced electro-catalytic activity (2.23 mA cm−2 at 0.85 V) and stability for oxygen reduction reaction. In alkaline solution, the ORR onset potential and half-wave potential of the Ag9Pd1 alloy nanoactiniae can reach a value of 1.02 V and 0.89 V, respectively, which origin from strong ligand and ensemble effects between Pd element and Ag element. The nanocrystals are uniformly alloyed, displaying a Ag9Pd1 combination, as displayed by an assembly of X-ray diffraction (XRD) spectrum, energy dispersive X-ray (EDX) analysis, and cyclic voltammetry (CV). This concept of tuning bimetallic alloy nanocrystals with low concentrations of more precious metal may be a promising approach to be applicable to a wide range of alloy nanocrystals.

Simultaneously engineering the size and surface crystal facets of bimetallic core-shell nanocrystals offers an effective route to not only reduce the extravagance of innermost core metal and maximize the utilization efficiency of shell atoms but also strengthen the core-to-shell interaction via ligand and/or strain effects. Herein, we systematically study the architecture transition and crystal facet engineering at the atomic level on the surface of sub-5 nm Pd(111) tetrahedrons (Ths), aimed at embodying how the variations in the local facet and shape of a sub-10 nm core-shell structure affect its surface geometrical properties and electronic structures. Specifically, surface atomic replication is predominant when the shell metal deposits less than five atomic layers, thus forming a series of Pd@M (M = Pt, Ru, and Rh) core-shell Ths enclosed by (111) facets (∼6.8 nm), while over five atomic layers, spontaneous facets tropism of each metal is predominant, where Pt atoms still follow fcc-(111) packing, Ru atoms select hcp-phase stacking, and Rh atoms choose fcc-(100) crystallization, respectively. In particular, Pt atoms take a seamless geometrical transformation from Pd@Pt Ths into Pd@Pt truncated octahedrons (TOhs, ∼7.6 nm). As a proof-of-concept application, such sub-10 nm core-shell architectures with Pt skin show a component-dependent relationship toward oxygen reduction reaction (ORR), where the catalytic activity follows the order of Pd@Pt(111) TOhs (E1/2 = 0.916 V, 1.632 A mgPt-1) > Pd@Pt(111) Ths > Pt black. Meanwhile the Ru skin show a facet-dependent relationship toward acidic hydrogen evolution reaction (HER) where the catalytic activity follows the order of Pd@Ru(111) Ths > Pd@Ru(hcp) Ths > Pd Ths.

A feasible and green sol-gel method is proposed to fabricate well-distributed nano-particulate Fe-Ni2P incorporated in N, P-codoped porous carbon nanosheets (Fe-Ni2P@N,P-CNSs) using biomass agarose as a carbon source, and ethylenediamine tetra (methylenephosphonic acid) (EDTMPA) as both the N and P source. The doped Fe in Ni2P is essential for a substantial increase in intrinsic catalytic activity, while the combined N,P-containing porous carbon matrix with a better degree of graphitization endows the prepared Fe-Ni2P@N,P-CNSs catalyst with a high specific surface area and improved electrical conductivity. Benefiting from the specific chemical composition and designed active site structure, the as-synthesized Fe-Ni2P@N,P-CNSs manifests a satisfying catalytic performance toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in an alkaline solution, with low overpotential, small Tafel slope and long-term durability, relative to the counterparts (Fe-free Ni12P5/Ni2P2O7@N,P-CNSs and CNSs) with single components and even comparable to Pt/C and RuO2 catalysts. The present work broadens the exploration of efficient bifunctional oxygen electrocatalysts using earth abundant biomass as carbon sources based on non-noble metals for low cost renewable energy conversion/storage.

It is a great challenge to simultaneously control the size, morphology, and facets of monodispersed Pd nanocrystals under a sub-5 nm regime. Meanwhile, quantitative understanding of the thermodynamic and kinetic parameters to maneuver the shape evolution of nanocrystals in a one-pot system still deserves investigation. Herein, a systematic study of the density functional theory (DFT)-calculated adsorption energy, thermodynamic factors, and reduction kinetics on Pd growth patterns is reported by combining theory and experiments, with a focus on the dispersed state of additives. As pure models, monodispersed Pd tetrahedrons enclosed by (111) facets with a narrow size distribution of 4.9 ± 1 nm and a high purity approaching 98% can be obtained when using 1,1'-binaphthalene (C20 H14 ) +2NH3 as additives. Specifically, laciniate Pd nanourchins (Pd LUs) can evolve via anisotropic growth when replacing additive with dose-consistent 1,1'-binaphthyl-2,2'-diamine (C20 H16 N2 , two NH2 binding in C20 H14 ). Catalytic investigations show that the sub-5 nm Pd tetrahedrons exhibit higher activity in both the oxygen reduction (Eonset = 1.025 V, E1/2 = 0.864 V) and formic acid oxidation reaction with respect to the Pd LUs and Pd black, which represents a great step for the development of well-defined Pd nanocrystals with size in the sub-5 nm regime as non-Pt electrocatalysts.