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Metal-organic frameworks (MOFs) with carboxylate ligands as co-catalysts are very efficient for the oxygen evolution reaction (OER). However, the role of local adsorbed carboxylate ligands around the in-situ-transformed metal (oxy)hydroxides during OER is often overlooked. We reveal the extraordinary role and mechanism of surface-adsorbed carboxylate ligands on bi/trimetallic layered double hydroxides (LDHs)/MOFs for OER electrocatalytic activity enhancement. The results of X-ray photoelectron spectroscopy (XPS), synchrotron X-ray absorption spectroscopy, and density functional theory (DFT) calculations show that the carboxylic groups around metal (oxy)hydroxides can efficiently induce interfacial electron redistribution, facilitate an abundant high-valence state of nickel species with a partially distorted octahedral structure, and optimize the d-band center together with the beneficial Gibbs free energy of the intermediate. Furthermore, the results of in situ Raman and FTIR spectra reveal that the surface-adsorbed carboxylate ligands as Lewis base can promote sluggish OER kinetics by accelerating proton transfer and facilitating adsorption, activation, and dissociation of hydroxyl ions (OH- ).

Electrocatalytic water splitting is considered as a promising route to use renewable energy for hydrogen production; however, its industrial application is limited by the anodic reaction, oxygen ev...

Ultra-high temperature ceramics have been considered as good candidates for plasma facing materials due to their combination of high melting point, high strength and hardness, high thermal conductivity as well as good chemical inertness. In this study, zirconium diboride has been chosen to investigate its irradiation damage behavior. Irradiated by 4 MeV Au2+ with a total fluence of 2.5 × 1016 cm−2, zirconium diboride ceramic shows substantial resilience to irradiation-induced damage with its structural integrity well maintained but mild damage at lattice level. Grazing incident X-ray diffraction evidences no change of the hexagonal structure in the irradiated region but its lattice parameter a increased and c decreased, giving a volume shrinkage of ∼0.46%. Density functional theory calculation shows that such lattice shrinkage corresponds to a non-stoichiometric compound as ZrB1.97. Electron energy-loss spectroscopy in a transmission electron microscope revealed an increase of valence electrons in zirconium, suggesting boron vacancies were indeed developed by the irradiation. Along the irradiation depth, long dislocations were observed inside top layer with a depth of ∼750 nm where the implanted Au ions reached the peak concentration. Underneath the top layer, a high density of Frank dislocations is formed by the cascade collision down to a depth of 1150 nm. All the features show the potential of ZrB2 to be used as structural material in nuclear system.

Optimizing the coordination/surrounding environments of active metal nanoclusters to promote the catalytic performance during hydrogen evolution reaction (HER) in alkaline media is highly important but extremely challenging. Here, we demonstrate that novel S-coordinated ruthenium (Ru) nanoclusters anchored on N/S-codoped carbon nanosheets (Ru–S/N–C) can be successfully synthesized via the space-confinement pyrolysis of Ru complexes in the framework of polyaniline–ammonia persulfate supermolecules. X-ray absorption fine structure spectroscopy and X-ray photoelectron spectroscopy studies reveal the local coordination structure of Ru–S bonds, the surrounding N/S/C environments of Ru, and the synergistic electronic interactions among N, S, C and Ru atoms. Theoretical calculations further confirm that the coordination/surrounding environments could optimize the adsorption energies of intermediates on Ru through interfacial charge transfer and, thus, accelerate the reaction kinetics of hydrogen evolution. The fabricated Ru–S/N–C exhibits an ultra-small overpotential of 10 mV at 10 mA cm−2 and an extremely high turnover frequency (TOF) of 2.3 H2 s−1 at an overpotential of 50 mV for the HER, as well as a mass catalytic activity about 10 times higher than that of a commercial Pt/C catalyst.

The intrinsic activity of NiFe layer double hydroxides (LDHs) for the oxygen evolution reaction (OER) suffers from its predominantly exposed (003) basal plane, which is thought to have poor activity. Herein, we construct a hierarchal structure of NiFe LDH nanosheet-arrays-on-microplates (NiFe NSAs-MPs) to elevate the electrocatalytic activity of NiFe LDHs for the OER by exposing a high-activity plane, such as the (012) edge plane. It is surprising that the NiFe NSAs-MPs show activity of 100 mA cm−2 at an overpotential (η) of 250 mV, which is five times higher than that of (003) plane-dominated NiFe LDH microsheet arrays (NiFe MSAs) at the same η, representing the excellent electrocatalytic activity for the OER in alkaline media. Besides, we analyzed the OER activities of the (003) basal plane and the (012) and (110) edge planes of NiFe LDHs by density functional theory with on-site Coulomb interactions (DFT+U), and the calculation results indicated that the (012) edge plane exhibits the best catalytic performance among the various crystal planes because of the oxygen coordination of the Fe site, which is responsible for the high catalytic activity of NiFe NSAs-MPs., The (012) edge plane of NiFe layer double hydroxides (LDHs) has been proven to be a highly active plane for water oxidation.

We report a success in synthesizing high entropy silicides (HES) compounds and manufacturing well-densified HES ceramics through spark plasma sintering. For a designed chemical formula as (Ti0.2Zr0.2Nb0.2Mo0.2W0.2)Si2, the as-synthesized HES showed a formula as (Ti0.22Zr0.06Nb0.29Mo0.22W0.21)Si2 with zirconium partially oxidized into zirconia. Doping with aluminum resulted in a HES with the same composition, promoted formation of ZrSi2 and Al2O3. XRD analysis of as-synthesized HES is well supported by the calculated diffraction data based on a 2 × 3 × 1 supercell with HCP crystal structure and experimental chemical composition. The cations in this HES crystal structure can occupy their positions randomly with little change of its lattice parameters and formation enthalpy.

Here, we report the successful fabrication of highly dispersed ultrafine Ni nanoparticles (NPs) embraced into the partially carbonized Ni-MOF-74 (Ni NPs/C@Ni-MOF-74) microrod arrays by the heat treatment of the rod-like Ni-MOF-74 arrays grown on Ni foam. The partial carbonization is an effective strategy to realize the homogeneous dispersion of ultrafine Ni NPs and carbon in the skeleton of rod-like Ni-MOF-74. This can prevent the encapsulated Ni NPs and carbon from aggregation and oxidation, allowing them to serve as highly efficient electrocatalysts. The fabricated Ni NPs/C@Ni-MOF-74 not only provide high specific surface area and high conductivity, but also provide good hydrophilicity and synergetic effects among Ni NPs, carbon and Ni-MOF-74 for the adsorption and activation of H2O molecules. The HER electrocatalytic performance of Ni NPs/C@Ni-MOF-74 arrays can be optimized by the control of the carbonization time and temperature. The optimized Ni NPs/C@Ni-MOF-74/NF shows outstanding HER catalytic performance, with a low overpotential of 131 mV at 10 mA cm−2 and excellent durability, and it is superior to most of the recently reported MOF-based HER electrocatalysts.

Aims: We aim to perform a systematic review and meta-analysis examining randomized controlled trials assessing the efficacy and safety of sacubitril/valsartan in patients on renal outcomes, in comparison with the renin–angiotensin–aldosterone system inhibitor (RAASi).Methods: Eligible studies were retrieved on MEDLINE, EMBASE, and Cochrane until September 2021. The primary outcome was the incidence of renal impairment, which was defined as the composite of increases in serum creatinine by >0.3 mg/dl and/or a reduction in eGFR ≥25%, development of ESRD, or renal death. We pooled relative risks (RRs) with 95% confidence intervals (CIs) or the mean difference with 95% CIs for the variables.Results: Our search yielded 10 randomized controlled trials with a total of 18,362 patients. Compared with RAASi treatment, patients treated with sacubitril/valsartan had lower incidence of composite renal impairment (10 studies, 18,362 patients, RR 0.84; 95% CI 0.72–0.96, p = 0.01; I2 = 22%), ESRD development (3 studies, 13,609 patients, RR 0.53; 95% CI 0.30–0.96, p = 0.03; I2 = 0%), drug discontinuation due to renal events (4 studies, 9,995 patients, RR 0.58; 95% CI 0.40–0.83, p = 0.003; I2 = 47%), severe hyperkalemia (6 studies, 16,653 patients, RR 0.80; 95% CI 0.68–0.93, p = 0.01; I2 = 25%) and a slower eGFR decline (4 studies, 13,608 patients, WMD 0.56; 95% CI 0.36–0.76, p I2 = 65%). Subgroup analysis demonstrated that sacubitril/valsartan was associated with a lower incidence of renal impairment in patients with heart failure and preserved ejection fraction (HFpEF), but not in those with heart failure and reduced ejection fraction (HFrEF). The superior renal function preservation of sacubitril/valsartan treatment was not associated with different baseline eGFR levels and follow-up duration. There was a smaller increase in the change in the urine albumin-to-creatinine ratio (UACR) (3 studies, 9,114 patients, SMD 0.06; 95% CI 0.02–0.10, p = 0.003; I2 = 14%) with sacubitril/valsartan treatment. However, patients with heart failure appeared to have increased microalbuminuria, not patients without HF (p = 0.80 for interaction).Conclusion: Sacubitril/valsartan was associated with a lower incidence of composite renal impairment especially in patients with HFpEF, but higher microalbuminuria in patients with heart failure (both HFrEF and HFpEF) compared with RAASi. The lower incidence of severe hyperkalemia and drug discontinuation due to renal events in patients with sacubitril/valsartan treatment demonstrated its superior safety compared with RAASi.

Searching for a highly efficient electrocatalyst for the hydrogen evolution reaction (HER) in alkaline solution is still challenging. In this work, we report a HER electrocatalyst composed of Ni foam, Ni3S2, and nitrogen-doped carbon nanotubes (NF@Ni3S2@NCNTs). The good lattice matching between Ni and Ni3S2, interstitial doping of C and N atoms, and synergistic effect of NCNTs make NF@Ni3S2@NCNTs highly efficient HER electrocatalysts in alkaline solution. NF@Ni3S2@NCNTs exhibit an overpotential of 93.89 mV at a current density of 10 mA cm-2, a Tafel slope of 54 mV dec-1, and superior stability for HER in 1 M KOH solution. Our findings will promote the reasonable design and synthesis of an efficient electrocatalyst for HER in alkaline electrolytes.

Metal-organic frameworks (MOFs) with carboxylate ligands as co-catalysts are very efficient for oxygen evolution reaction (OER). However, the role of local adsorbed carboxylate ligands around the in situ transformed metal (oxy)hydroxides during OER is often overlooked. Here we reveal the extraordinary role and mechanism of surface adsorbed carboxylate ligands on bi/trimetallic layered double hydroxides (LDHs)/MOFs for OER catalytic activity enhancement. The results of X-ray photoelectron spectroscopy (XPS), synchrotron X-ray absorption spectroscopy and theoretical calculations show that the carboxylic groups around metal (oxy)hydroxides can efficiently induce the interfacial electron redistribution, facilitate abundant high-valence state of nickel species with partial distorted octahedral structure, and optimize the d-band center together with the beneficial Gibbs free energy of intermediate. Furthermore, the results of in-situ Raman and FI-IR spectra firstly reveal that the surface adsorbed carboxylate ligands as Lewis base can promote the sluggish OER kinetics by accelerating proton transfer and facilitating adsorption/ activation/dissociation of hydroxyl ions (OH−). Our findings will offer unique insights into the reason for disclosing the origin of excellent electrocatalytic activity for MOF/NiFe-LDHs catalysts.

Realizing synergetic effect of multiple factors is critical to develop an optimal catalyst. Bimetallic oxides have shown great potential for catalytic hydrogen evolution from water splitting in alkaline media because their oxygen species are beneficial for water adsorption and can get unique d electron configurations to optimize the binding strength of intermediates. Here bimetallic oxide heterointerface CoMoO4/Co2Mo3O8 with rich-oxygen vacancies (Vo) incorporated by the monodisperse small-size cobalt (Co) nanoparticles (Co@CoMoO4/Co2Mo3O8-Vo) is designed for hydrogen evolution reaction (HER) in alkaline media. The charge redistribution occurs at the CoMoO4/Co2Mo3O8 interface because of incorporation of Co, and this will be helpful for H* adsorption and interfacial electron transferring. Meanwhile, the rich-oxygen vacancies can well optimize the binding energy of intermediate species on CoMoO4/Co2Mo3O8 interface and thus will facilitate the sluggish HER in alkaline media. Because of the synergistic effects of metallic Co, CoMoO4/Co2Mo3O8 interfaces and rich-oxygen vacancies, the Co@CoMoO4/Co2Mo3O8-Vo catalyst shows superior electrocatalytic activity for HER in alkaline media with a low overpotential of 60 mV at 10 mA cm-2, a small Tafel slop of 52 mV dec-1, and excellent durability with ∼2% degradation after 24 h test. This work will provide a new strategy to enhance HER catalytic performance of bimetallic oxides in alkaline media.

The tremendous works focusing on long-range ordered hydroxides have ignored the investigation of the edge/corner sites in hydroxides, which is recently believed to be crucial for electrocatalytic activity enhancement of oxygen evolution reaction (OER). In this study, by anodic galvanostatic treatment in (NH4)2Fe(SO4)2 solution, the amorphous Ni(OH)2 (am-Ni(OH)2) is transformed into a short-range ordered Fe substituted-Ni(OH)2 (so-Fe-Ni(OH)2), which contains abundant electroactive edge/corner sites. To further enhance surface area, the special tube-in-tube arrays (TTAs) are fabricated for so-Fe-Ni(OH)2 to accelerate the reaction kinetics of OER. From DFT calculation, the low-coordinated defect sites with Fe-Ni-Fe units caused by the short-range ordered structure of so-Fe-Ni(OH)2 TTAs facilitate the formation of adsorbed oxygen, which is rate-determining step for efficient OER. The so-Fe-Ni(OH)2 TTAs show higher OER performance than long-range ordered Fe substituted-Ni(OH)2 (lo-Fe-Ni(OH)2). This study will provide a new strategy for electroactive edge/corner-site engineering of hydroxide-based electrocatalysts for efficient OER.

The efficient bifunctional catalysts for hydrogen and oxygen evolution reactions (HER/OER) have attracted great interest for hydrogen production from water splitting. Herein, the doping and vacancy double control strategy for the design of bifunctional catalysts is firstly demonstrated for the significant enhancement of HER/OER catalytic performances by constructing Fe doped-Ni5P4/Fe-doped Ni(OH)2 (Fe-Ni5P4/NiFeOH) hybrid nanosheets with rich oxygen vacancies. The experimental studies and first-principle calculations both prove that the combined effects of Fe doping and oxygen vacancy can easily regulate the electronic structure and accordingly optimize the adsorptions/desorptions of intermediates. The bifunctional Fe-Ni5P4/NiFeOH-350 shows small overpotentials of 197 and 221 mV for HER and OER, respectively, along with a low cell voltage of 1.55 V at 10 mA cm−2 and excellent long-term stability for water splitting.

Here we report the functional FeOOH as a cocatalyst to enhance excellent bifunctionality of the Ni3N catalyst, which demonstrate remarkable electrocatalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reduction (OER) compared to the pristine Ni3N sample. Experimental data and theoretical calcinations demonstrate that the FeOOH facilitates surface adsorption and cleavage of OH−/H2O species and decrease the d-band center of active Ni species for optimizing the Gibbs free energy of intermediates. Furthermore, relatively vertical Ni3N nanotubes can promote the mass transport and electrons transfer as a main catalyst. The unusual synergistic effect in hybrid system with high density of heterointerface is contributed to the improvement of HER/OER catalytic performance. Specifically, the obtained FeOOH/Ni3N hybrid catalysts display excellent OER/HER performance with an overpotential of 244 mV/67 mV at 10 mA cm−2 in 1.0 M KOH, along with an applied potential of 1.58 V to boost overall water splitting at 10 mA cm−2. This simple and effective strategy may provide a new path to design the bifunctional catalysts and improve the catalytic performance for water splitting.