Ni-Ru supported on CeO2 obtained by mechanochemical milling for catalytic hydrogen production from ammonia.

Developing active and stable catalysts for carbon-free hydrogen production is crucial to mitigate the effects of climate change. Ammonia is a promising carbon-free hydrogen source, as it has a high hydrogen content and is liquid at low pressure, which allows its easy storage and transportation. We have recently developed a nickel-based catalyst with a small content of ruthenium supported on cerium oxide, which exhibits high activity and stability in ammonia decomposition. Here, we investigate mechanochemical milling for its synthesis, a faster and less energy-consuming technique than conventional ones. Results indicate that mechanochemical synthesis increases catalytic activity compared to the conventional incipient wetness impregnation method. The interaction between the metal precursors and the support is key in fine-tuning catalytic activity, which increases linearly with oxygen vacancies in the support. Moreover, the mechanochemical method modifies the oxidation state of Ni and Ru species, with a variation depending on the precursors.

Investigation of the evolution of Pd-Pt supported on ceria for dry and wet methane oxidation.

Efficiently treating methane emissions in transportation remains a challenge. Here, we investigate palladium and platinum mono- and bimetallic ceria-supported catalysts synthesized by mechanical milling and by traditional impregnation for methane total oxidation under dry and wet conditions, reproducing those present in the exhaust of natural gas vehicles. By applying a toolkit of in situ synchrotron techniques (X-ray diffraction, X-ray absorption and ambient pressure photoelectron spectroscopies), together with transmission electron microscopy, we show that the synthesis method greatly influences the interaction and structure at the nanoscale. Our results reveal that the components of milled catalysts have a higher ability to transform metallic Pd into Pd oxide species strongly interacting with the support, and achieve a modulated PdO/Pd ratio than traditionally-synthesized catalysts. We demonstrate that the unique structures attained by milling are key for the catalytic activity and correlate with higher methane conversion and longer stability in the wet feed.

Facing Seawater Splitting Challenges by Regeneration with Ni-Mo-Fe Bifunctional Electrocatalyst for Hydrogen and Oxygen Evolution.

Hydrogen, produced by water splitting, has been proposed as one of the main green energy vectors of the future if produced from renewable energy sources. However, to substitute fossil fuels, large amounts of pure water are necessary, scarce in many world regions. In this work, we fabricate efficient and earth-abundant electrodes, study the challenges of using real seawater, and propose an electrode regeneration method to face undesired salt deposition. Ni-Mo-Fe trimetallic electrocatalyst is deposited on non-expensive graphitic carbon felts both for hydrogen (HER) and oxygen evolution reactions (OER) in seawater and alkaline seawater. Cl- pitting and the chlorine oxidation reaction are suppressed on these substrates and alkalinized electrolyte. Precipitations on the electrodes, mainly CaCO3 , originating from seawater-dissolved components have been studied, and a simple regeneration technique is proposed to rapidly dissolve undesired deposited CaCO3 in acidified seawater. Under alkaline conditions, Ni-Mo-Fe-based catalyst is found to reconfigure, under cathodic bias, into Ni-Mo-Fe alloy with a cubic crystalline structure and Ni : Fe(OH)2 redeposits whereas, under anodic bias, it is transformed into a follicular Ni:FeOOH structure. High productivities over 300 mA cm-2 and voltages down to 1.59 V@10 mA cm-2 for the overall water splitting reaction have been shown, and electrodes are found stable for over 24 h without decay in alkaline seawater conditions and with energy efficiency higher than 61.5 % which makes seawater splitting promising and economically feasible.

Histopathology of chronic kidney disease of unknown etiology in Salvadoran agricultural communities.

INTRODUCTION: For at least a decade, a chronic kidney disease unassociated with diabetes mellitus, hypertension or any of the more common traditional causes, has been reported in Salvadoran agricultural communities. OBJECTIVE: Characterize histopathology of chronic kidney disease of unknown etiology in patients from Salvadoran agricultural communities, describe renal damage associated with each disease stage, and assess associations between histopathological alterations and sociodemographic variables. METHODS: The study involved 46 patients of both sexes, aged =18 years. After clinical, laboratory and imaging examinations, kidney biopsies were performed and renal tissue assessed for interstitial fibrosis, tubular atrophy, interstitial inflammatory infiltration, sclerosis, increase in glomerular size and extraglomerular vascular lesions (according to the Banff 97 classification used for kidney transplant rejection). Special staining was done: Schiff periodic acid, Masson trichrome and methenamine silver. Immunofluorescence techniques were used to evaluate IgA, IgG, IgM, complement C1q and C3, fibrin, and kappa and lambda light chain deposits. RESULTS: The main findings were interstitial fibrosis and tubular atrophy with or without inflammatory monocyte infiltration. In addition, generalized sclerosis, increased glomerular size, collapse of some glomerular tufts, and lesions of extraglomerular blood vessels (such as intimal proliferation and thickening and vacuolization of the tunica media) were observed. Interstitial fibrosis and glomerulosclerosis were associated with male sex. Sugarcane workers showed more interstitial fibrosis and tubular atrophy and less glomerulomegaly than other occupational groups. CONCLUSION: The morphological pattern in all biopsies was one of chronic tubulointerstitial nephropathy with secondary glomerular and vascular damage, in different stages of evolution of chronic kidney disease, independent of age, sex or occupation.