Co(III) carboxamide complexes as electrocatalysts for water splitting

Water splitting is a promising approach for storing intermittent renewable energies, such as sunlight in the clean chemical bonds as a hydrogen fuel. Two water-soluble octahedral cobalt (III) complexes, [Co(bpb)(OAc)(H₂O)], 1, (bpb^2? = N,N′-bis[(2-pyridine carboxamide)-1,2-benzene] dianion) and [Co(cbpb)(OAc)(H₂O)], 2, (cbpb^2? = N,N′-bis[(2-pyridine carboxamide)-4-chloro-1,2-benzene] dianion) were synthesised and characterised by CHN elemental analysis, UV–Vis, FT-IR and single-crystal X-ray diffraction techniques. The two carboxamide ligands had been prepared in the ionic liquid TBAB as an environmentally benign reaction medium. The electrocatalytic water splitting activity of 1 and 2 showed that both complexes are highly active for the water splitting in aqueous solutions. Turn Over Frequency (TOF) values were, for 1 and 2 respectively, 527 and 490 mol of hydrogen in each mole of catalyst per hour at an overpotential of 738 mV (pH = 7.0). Such a performance can be ascribed to the flat ligands, the electroactivity of the metal centre and carboxamide ligands and the ability of losing the axial ligands around the metal-ion centre during the reduction process which provide different reduction pathways for an HER process.     

Strengthened Synergistic Effect of Metallic MxPy (M = Co,Ni, and Cu) and Carbon Layer via Peapod‐Like Architecture for Both Hydrogen and Oxygen Evolution Reactions

The smooth electric transmission is crucial for the high‐efficient electrocatalysis. Herein, a series of peapod‐like metallic M_xP_y/C (M = Co, Ni, and Cu) composites is developed as bifunctional catalysts toward hydrogen and oxygen evolution reactions. For the first time, the metallic property of Cu₃P is confirmed through the theoretical calculation. The in‐depth composition, structural and catalytic mechanism analysis of M_xP_y/C discloses that the comparable activity and considerable durability of these catalysts mainly result from the strengthened synergistic effect between metallic M_xP_y and carbon layer based on the unique peapod‐like architecture. Especially, the atomic contact between M_xP_y and carbon not only provides an open channel for electronic transmission but also ensures the integrity of peapod‐like structure. Furthermore, the high electric conductivity of the inner metallic M_xP_y and the outer carbon layer endows the M_xP_y/C catalyst with rapid charge migration during the electrocatalytic pathway. These findings shed light on the origin of high catalytic activity of M_xP_y/C and open a path for purposefully rationally synthesizing superior electrocatalysts.     

Tetra-carboxylic acid based metal-organic framework as a high-performance bifunctional electrocatalyst for HER and OER

Tetra-carboxylic acid based 3D porous MOFs 1 and 2, named {[Co_2.5(L)]·5H₂O}_n and 0.5{[Cu(L)]·2H₂O}_n (L = 4,4′-di(ethoxy)biphenyl-3,3′,5,5′-tetra-(phenyl-4-carboxylic acid)), bearing metal clusters have been facilely constructed by hydrothermal synthesis. Structural studies indicate that 1 presents a 3-nodal (4, 4, 8)-connected topology with the point notation of {4⁴.6²}2{4⁸.6⁷.8¹³}, while 2 shows a uninodal (4, 4)-connected network with point symbol of {4⁴.6²}. The pristine MOFs are directly utilized for electrocatalysis and poor HER activities are obtained in alkaline solution, which promote the further design and fabrication of a mixed-metal Co/Cu-MOF (3). As expected, 3 shows significantly improved performances for HER with overpotential of 391 mV (10 mA cm⁻² current density), low Tafel slope of 94 mV dec⁻¹ and long-term operation stability (14 h). More importantly, the direct utilization of 3 for accelerating OER also presents a fascinating performance in overpotential at 10 mA cm⁻² current and durability. The above electrocatalytic performance of pristine 3 can be ascribed to the result of hybridizing strategy for constructing MOFs under hydrothermal procedure, which may favorably produces synergistic effect and more open metal sites. This work provides in-depth understanding of hybrid pristine MOFs for electrocatalysis.     

Identification of the anti-triangular etched MoS2 with comparative activity with commercial Pt for hydrogen evolution reaction

The introduction of anti-triangular dots by etching MoS₂ has been recently reported as an efficient way to produce active internal edges. However, it is still ambiguous to identify the configuration of etched MoS₂ with comparative hydrogen evolution reaction (HER) activity to commercial Pt. In this work, the HER activity on etched anti-triangular MoS₂ are investigated by density functional theory calculations. We found the valence electron distribution of inner edge atoms can be affected by the corner, and accordingly determine their activity. The second-nearest atom to anti-triangular corner possesses the highest activity. The simulated polarization curves show etched anti-triangular Mo-edge MoS₂ with moderate size (around 12 Å) maximize the HER performance. Further increasing size of etched MoS₂ deactivate their HER activity to a certain degree, validated by available experimental data. This work suggests etched MoS₂ catalysts with rational design may be a candidate to substitute Pt electrodes as HER electrocatalyst.     

Performance of nickel electrode for alkaline water electrolysis prepared by high pressure cold spray

To promote Ni electrode performance during water splitting, a novel coating process, High pressure cold spray, is applied to prepare electrodes from blended Ni + Al powder. By controlling Al fraction, electrodes are obtained with varied microstructure. SEM and EDX are implemented to check the micromorphology of electrodes. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) are performed to estimate the effect of Al addition on electrode performance. Resultantly, significant improvement of electrode performance is achieved by increasing the fraction of Al from 10 vol% to 20 vol%. The obtained coatings are found with numerous pores owing to the removal of Al during the activation. By applying electrochemical test, the HER of all samples are dominated by Volmer step, and sample N20A is found with the highest active surface area. Thus, sample N20A exhibits the highest electro-catalytic activity to HER of alkaline water electrolysis.     

Protein Corona Gold Nanoparticles Fingerprinting Reveals a Profile of Blood Coagulation Proteins in the Serum of HER2-Overexpressing Breast Cancer Patients

Breast cancer (BC) is a molecularly heterogeneous disease that encompasses five major molecular subtypes (luminal A (LA), luminal B HER2 negative (LB-), luminal B HER2 positive (LB+), HER2 positive (HER2+) and triple negative breast cancer (TNBC)). BC treatment mainly depends on the identification of the specific subtype. Despite the correct identification, therapies could fail in some patients. Thus, further insights into the genetic and molecular status of the different BC subtypes could be very useful to improve the response of BC patients to the range of available therapies. In this way, we used gold nanoparticles (AuNPs, 12.96 ± 0.72 nm) as a scavenging tool in combination with Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) to quantitatively analyze the serum proteome alterations in the different breast cancer intrinsic subtypes. The differentially regulated proteins specific of each subtype were further analyzed with the bioinformatic tools STRING and PANTHER to identify the major molecular function, biological processes, cellular origin, protein class and biological pathways altered due to the heterogeneity in proteome of the different BC subtypes. Importantly, a profile of blood coagulation proteins was identified in the serum of HER2-overexpressing BC patients.     

Synergistic Phase and Disorder Engineering in 1T‐MoSe2 Nanosheets for Enhanced Hydrogen‐Evolution Reaction

MoSe₂ is a promising earth‐abundant electrocatalyst for the hydrogen‐evolution reaction (HER), even though it has received much less attention among the layered dichalcogenide (MX₂) materials than MoS₂ so far. Here, a novel hydrothermal‐synthesis strategy is presented to achieve simultaneous and synergistic modulation of crystal phase and disorder in partially crystallized 1T‐MoSe₂ nanosheets to dramatically enhance their HER catalytic activity. Careful structural characterization and defect characterization using positron annihilation lifetime spectroscopy correlated with electrochemical measurements show that the formation of the 1T phase under a large excess of the NaBH₄ reductant during synthesis can effectively improve the intrinsic activity and conductivity, and the disordered structure from a lower reaction temperature can provide abundant unsaturated defects as active sites. Such synergistic effects lead to superior HER catalytic activity with an overpotential of 152 mV versus reversible hydrogen electrode (RHE) for the electrocatalytic current density of j = ?10 mA cm^?2, and a Tafel slope of 52 mV dec^?1. This work paves a new pathway for improving the catalytic activity of MoSe₂ and generally MX₂‐based electrocatalysts via a synergistic modulation strategy.     

Construction of Nickel-Based Dual Heterointerfaces towards Accelerated Alkaline Hydrogen Evolution via Boosting Multi-Step Elementary Reaction

The introduction of composite components to construct heterointerfaces is an important way to improve the electrocatalytic performance of materials. However, selecting appropriate components to accelerate the elementary reaction rates of the hydrogen evolution reaction (HER) in alkaline media is still in challenge. Here, a Ni-CeF₃-VN multi-component material is successfully constructed, which exhibits excellent HER catalytic activity (33 mV at 10 mA cm⁻²). The experimental and computational results show that the Ni-VN and Ni-CeF₃ dual heterointerfaces can effectively promote the transfer of OH⁻ adsorption site from Ni to VN and optimize the adsorption energy of intermediate H respectively, which together accelerate the rate of the multi-step hydrogen evolution reaction in alkaline solution and thus lead to a significantly improved HER performance compared to the pure Ni. Furthermore, the solar to hydrogen (STH) efficiency can reach 10.34%. This work provides an effective guide for the design of high-efficiency multicomponent materials in the future.