Release Of Hydrogen Gas Research Articles

Treatment of Landfill Leachate by Electrocoagulation using Aluminium Electrodes by Renewable Energy

Leachate is wastewater produced from decomposition of organic waste that can pollute soil and groundwater if it is not handle properly. Pollution by leachate can be prevented by treating the leachate before disposing to environment. One of the methods used is electrocoagulation. Electrocoagulation is an electrochemical water treatment method where anode releases the active coagulant as metalic ion, while in cathode the electrolysis reaction, release of hydrogen gas takes place. This Experimental study is mainly to investigate the efficiency or effectiveness of electrocoagulation in removing Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Turbidity of leachate. In this research, the processing of leachate with electrocoagulation method using aluminium electrode has been proceed with the dimension of electrode 90 mm x 30 mm x 1 mm.The effective volume of the reactor was 750 ml. electrocoagulation for each parameter are in the current density 4.96mA/cm2 with varying time from 0- 60 minutes(10,20,30,40,50,60,), at varying pH of 2-8(2,4,6,8) and at varying current supply of 3V-9V(3,6,9). Solar energy is used as source of energy, with the help of solar panels solar energy is converted to electrical energy and supplied to electrodes. In results the electrocoagulation method is effectively reduced the value of BOD 76.49%; COD 92.99%; Turbidity 87.17%. and we got effective results at paramameter of pH 6, at experimental time of 40 minutes and at current voltage 9V. Electrocoagulation method are successfully reduced the levels of pollutants in accordance with environmental standard.

Electrophoretic Deposition of Magnesium Oxide Nanoparticles on Magnesium: Processing Parameters, Microstructures, Degradation, and Cytocompatibility.

Magnesium (Mg) and its alloys are a class of promising materials for biodegradable orthopedic and craniomaxillofacial implants; however, rapid release of hydrogen gas remains a key challenge for clinical translation. This study reported the optimal parameters of electrophoretic deposition (EPD), at which magnesium oxide nanoparticles (nMgO) could be deposited onto Mg substrates with homogeneous surface morphology and elemental distribution. The results showed that the distribution and uniformity of the nMgO coatings on Mg improved when the nMgO concentration in ethanol increased and the time of applied voltage decreased. The nMgO-coated Mg showed a homogeneous surface and distinct degradation mode during the 9-day immersion studies in revised simulated body fluid (r-SBF) and Dulbecco's modified Eagle's medium (DMEM), when compared with the noncoated Mg controls. The nMgO coating initially mitigated hydrogen gas formation. The degradation layer on nMgO-coated Mg was thicker than the noncoated Mg and enriched with Ca and P that are favorable for skeletal implant applications. In the direct culture study with bone marrow derived mesenchymal stem cells (BMSCs) in vitro, the cell adhesion density and morphology were not affected by the solubilized degradation products released by the nMgO-coated Mg under indirect contact. However, at the cell-biomaterial interface, the cell spreading decreased under direct contact, possibly because of the continuous dynamic degradation of the samples. The electrophoretically deposited nMgO coatings on Mg-based medical implants should be further studied to improve the coating-substrate and cell-material interfaces for clinical applications.

Ruthenium Catalyzed Dehydrogenation of Alcohols and Mechanistic Study.

We synthesized pyridylamine ligated arene-Ru(II) complexes and employed these complexes for the catalytic acceptorless dehydrogenation of primary alcohols to carboxylic acids. All the synthesized complexes [Ru]-1-[Ru]-10 are characterized using several spectro-analytical techniques, and the structures of complexes [Ru]-1, [Ru]-2, and [Ru]-5 are determined using single crystal X-ray crystallography. Efficient catalytic conversion of primary alcohols to potassium carboxylates or carboxylic acids is achieved in toluene with the quantitative release of hydrogen gas. The studied protocol for carboxylic acid synthesis with hydrogen generation is also employed for a wide range of substrates, including aliphatic alcohols, aromatic alcohols, and heteroaromatic alcohols, to obtain respective carboxylic acids in good yields (up to 86%). The studied arene-Ru catalysts also exhibit superior catalytic activity for the bulk reaction to achieve a turnover number of 1378. Moreover, extensive mass investigations are also performed to elucidate the mechanistic pathway by identifying the crucial catalytic intermediates, including aldehyde and diol coordinated Ru species under the catalytic and controlled reaction conditions.

항만 내 컨테이너 위험물 저장 시 위험성 평가 및 개선방안

In this study, investigate the risk of storing dangerous goods in the port. The volume shipped by container ships doubled in 2014 from 2010 as the volume of maritime risk through ports steadily increased. Against this backdrop, when firefighters used fire water at a logistics warehouse in Tianjin, China in 2015, sodium cyanide and ammonium nitrate reacted, releasing hydrogen gas and causing 1.3 trillion won in property damage. Since then, the Environment Ministry has prepared safety management guidelines for dangerous goods in the port through inspection by the Ministry of Environment. Container companies, however, have not used direct withdrawal to set up stores among exceptions in the guidelines due to lack of land. The purpose of this study is to assess and compare the risk of indoor and outdoor storage of hazardous materials through ALOHA.

Reversible Hydrogen Releasing and Fixing with Poly(Vinylfluorenol) through a Mild Ir-Catalyzed Dehydrogenation and Electrochemical Hydrogenation.

The radical polymerization of 2-vinylfluorenol, an alcohol derivative of vinylfluorene, gives poly(vinylfluorenol), which quantitatively releases hydrogen gas (≈110 mL per gram polymer at standard temperature and pressure) by simply warming at 100 °C with an iridium catalyst. A high population of fluorenol units in the polymer accomplishes a large formula-weight-based theoretical hydrogen density (1.0 wt%). The dehydrogenated ketone derivative, poly(vinylfluorenone), exhibits reversible negative-charge storage with a high density of 260 mAh g-1 . The electrolytically reduced poly(vinylfluorenone) is momentarily hydrogenated in the presence of an electrolyte with water as the hydrogen source to be converted to the original poly(vinylfluorenol). The formed poly(vinylfluorenol) almost quantitatively evolves hydrogen gas similar to the starting poly(vinylfluorenol). Both hydrogen and charge storage with the organic fluorenol/fluorenone polymer suggest a new type of energy-storage configuration.

Transition metal nanoparticle catalysts in releasing hydrogen from the methanolysis of ammonia borane

Ammonia borane (H3N·BH3, AB) is one of the promising hydrogen storage materials due to high hydrogen storage capacity (19.6% wt), high stability in solid state as well as in solution and nontoxicity. The methanolysis of AB is an alternative way of releasing H2 due to many advantages over the hydrolysis such as having high stability against self releasing hydrogen gas. Here we review the reports on using various noble or non-noble metal(0) catalysts for H2 release from the methanolysis of AB. Ni(0), Pd(0), and Ru(0) nanoparticles (NPs), stabilized as colloidal dispersion in methanol, are highly active and long lived catalysts in the methanolysis of AB. The catalytic activity, lifetime and reusability of transition metal(0) NPs show significant improvement when supported on the surface of solid materials. The supported cobalt, nickel, copper, palladium, and ruthenium based catalysts are quite active in H2 release from the methanolysis of AB. Rh(0) NPs are highly active catalysts in releasing H2 from the methanolysis of AB when confined within the void spaces of zeolite or supported on oxide nanopowders such as nanosilica, nanohydroxyapatite, nanoalumina or nanoceria. The oxide supported Rh(0) NPs can provide high activity with turnover frequency values as high as 218 min−1 and long lifetime with total turnover values up to 26,000 in generation of H2 from the methanolysis of AB at 25 °C. When deposited on carbon the bimetallic AgPd alloy nanoparticles have the highest activity in releasing H2 through the methanolysis of AB.

In Situ Generated Cobalt Catalyst for the Dehydrogenative Coupling of Alcohols and Amines into Imines

AbstractAn in situ formed cobalt catalyst is developed from cobalt(II)bromide, bis[2‐(diisopropylphosphino)‐4‐methylphenyl]amine and zinc metal. The catalyst mediates the acceptorless dehydrogenative coupling of alcohols and amines into imines with the release of hydrogen gas and the transformation is applied to the synthesis of a variety of imines from different alcohols and amines. The mechanism is investigated with labelled substrates and based on the results a cobalt(I) PNP complex is believed to be the catalytically active species which abstracts hydrogen gas from the alcohol through a metal ligand bifunctional pathway.

Embedding magnesium metallic particles in polycaprolactone nanofiber mesh improves applicability for biomedical applications

Magnesium (Mg) metal is of great interest in biomedical applications, especially in tissue engineering. Mg exhibits excellent in vivo biocompatibility, biodegradability and, during degradation, releases Mg ions (Mg2+) with the potential to improve tissue repair. We used electrospinning technology to incorporate Mg particles into nanofibers. Various ratios of Mg metal microparticles (<44 µm diameter) were incorporated into nanofiber polycaprolactone (PCL) meshes. Physicochemical properties of the meshes were analyzed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), mechanical tensile testing, X-ray diffractometry and UV–VIS spectrophotometry. Biological properties of meshes were evaluated in vitro and in vivo. Under mammalian cell culture conditions, Mg-containing meshes released hydrogen gas and relative amounts of free Mg2+ that reflected the Mg/PCL ratios. All meshes were non-cytotoxic for 3T3 fibroblasts and PC-12 pheochromocytoma cells. In vivo implantation under the skin of mice for 3, 8 and 28 days showed that Mg-containing meshes were well vascularized, with improved measures of inflammation and healing compared to meshes without Mg. Evidence included an earlier appearance and infiltration of tissue repairing macrophages and, after 28 days, evidence of more mature tissue remodeling. Thus, these new composite nanofiber meshes have promising material properties that mitigated inflammatory tissue responses to PCL alone and improved tissue healing, thus providing a suitable matrix for use in clinically relevant tissue engineering applications. Statement of SignificanceThe biodegradable metal, magnesium, safely biodegrades in the body, releasing beneficial byproducts. To improve tissue delivery, magnesium metal particles were incorporated into electrospun nanofiber meshes composed of a biodegradable, biocompatible polymer, polycaprolactone (PCL). Magnesium addition, at several concentrations, did not alter PCL chemistry, but did alter physical properties. Under cell culture conditions, meshes released magnesium ions and hydrogen gas and were not cytotoxic for two cell types. After implantation in mice, the mesh with magnesium resulted in earlier appearance of M2-like, reparative macrophages and improved tissue healing versus mesh alone. This is in agreement with other studies showing beneficial effects of magnesium metal and provides a new type of scaffold material that will be useful in clinically relevant tissue engineering applications.

Supplementation with hydrogen-producing composition confers beneficial effects on physiology and life span in Drosophila

Recently, molecular hydrogen (H2) has become known as a new class of antioxidants and redox-modulating interventions. Effects of H2 have been documented for many acute and chronic pathological conditions. The present study was aimed at determining the effect of hydrogen on the physiology and longevity of Drosophila. The flies were given a patented food supplement consisting of a mixture of inert salts with metallic magnesium, which reacted with acidic aqueous solutions, thereby releasing hydrogen gas. The supplementation with hydrogen-rich food prolonged the life span of the wild-type strain. To gain insights into the effect of hydrogen, we used previously generated mutant under-expressing redox-regulating enzymes, peroxiredoxins, in mitochondria. The hydrogen-releasing material lessened the severe shortening of life span of the mutant. Hydrogen also delayed the development of intestinal dysfunction caused by under-expression of peroxiredoxins in the intestinal epithelium. Hydrogen also averted a significant decrease in the mobility of mutant flies that under-expressed peroxiredoxins globally or in specific tissues. Together, the results showed that the introduction of hydrogen to aging or short-lived flies could increase their survival, delay the development of the intestinal barrier dysfunction and significantly improve physical activity.

In vitro and in vivo studies of Mg-30Sc alloys with different phase structure for potential usage within bone

Proper alloying magnesium with element scandium (Sc) could transform its microstructure from α phase with hexagonal closed-packed (hcp) structure into β phase with body-cubic centered (bcc) structure. In the present work, the Mg-30 wt% Sc alloy with single α phase, dual phases (α + β) or β phase microstructure were developed by altering the heat-treatment routines and their suitability for usage within bone was comprehensively investigated. The β phased Mg-30 wt% Sc alloy showed the best mechanical performance with ultimate compressive strength of 603 ± 39 MPa and compressive strain of 31 ± 3%. In vitro degradation test showed that element scandium could effectively incorporate into the surface corrosion product layer, form a double-layered structure, and further protect the alloy matrix. No cytotoxic effect was observed for both single α phased and β phased Mg-30 wt% Sc alloys on MC3T3 cell line. Moreover, the β phased Mg-30 wt%Sc alloy displayed acceptable corrosion resistance in vivo (0.06 mm y−1) and maintained mechanical integrity up to 24 weeks. The degradation process did not significantly influence the hematology indexes of inflammation, hepatic or renal functions. The bone-implant contact ratio of 75 ± 10% after 24 weeks implied satisfactory integration between β phased Mg-30 wt%Sc alloy and the surrounding bone. These findings indicate a potential usage of the bcc-structured Mg-Sc alloy within bone and might provide a new strategy for future biomedical magnesium alloy design. Statement of SignificanceScandium is the only rare earth element that can transform the matrix of magnesium alloy into bcc structure, and Mg-30 wt%Sc alloy had been recently reported to exhibit shape memory effect. The aim of the present work is to study the feasibility of Mg-30 wt%Sc alloy with different constitutional phases (single α phase, single β phase or dual phases (α + β)) as biodegradable orthopedic implant by in vitro and in vivo testings. Our findings showed that β phased Mg-30 wt%Sc alloy which is of bcc structure exhibited improved strength and superior in vivo degradation performance (0.06 mm y−1). No cytotoxicity and systematic toxicity were shown for β phased Mg-30 wt%Sc alloy on MC3T3 cell model and rat organisms. Moreover, good osseointegration, limited hydrogen gas release and maintained mechanical integrity were observed after 24 weeks’ implantation into the rat femur bone.

Rescue jack system applying hydrogen-absorbing alloys as a pressure source

This paper presents a flexible and compact rescue jack system that uses a hydrogen-absorbing alloy as its pressure source. The jack system comprises a container for the hydrogen-absorbing alloy and an end effector thin enough to be applied within a 2 mm-thick gap, made of a fiber-reinforced rubber bag. The hydrogen-absorbing alloy (LaNi4.45Co0.5Mn0.05), whose plateau pressure was set to near atmospheric pressure at 25 °C, released hydrogen gas when heated to 50 °C. Experiments showed the system could lift 100 kg at moderate speed when the alloy container was placed in hot water (50 °C). Moreover, the jack system could maintain a 50 mm lift of 100 kg for nearly 12 h—performance comparable with that of an air jack. This clearly indicates the fiber-reinforced rubber bag is a suitable end effector of the actuator. The proposed jack system has good potential for prompt rescue activities conducted by non-professional operatives.

Numerical modelling of release of subsonic and sonic hydrogen jets

For the general public to use hydrogen as a vehicle fuel, they must be able to handle hydrogen with the same degree of confidence as conventional liquid and gaseous fuels. For refuelling hydrogen cars, hydrogen is stored at high pressures up to 700 bar. The hazards associated with jet releases from accidental leaks of such highly pressurized storage must be considered since a jet release and dispersion can result in a fire or explosion. Therefore, it is essential to understand the dispersion characteristics of hydrogen to determine the extent of the flammable cloud when released from a high-pressure source. These parameters are very important in the establishment of the safety distances and sizes of hazardous zones. This paper describes the work done by us in modelling of dispersion of accidental releases of hydrogen, using the FRED (Fire Explosion Release Dispersion) software. The dispersion module in FRED is validated against experimental data available in the open literature for steady release and dispersion of cold and ambient hydrogen gas. The validation is performed for a wide range of hole sizes (0.5–4 mm), pressure (1.7–400 bar) and temperature (50–298 K).The model predictions of hydrogen gas jet velocity, concentration decay as a function of distance as well as radial concentration distribution are in good agreement with experiments. Overall, it is concluded that FRED can accurately model accidental release and dispersion of hydrogen in unconfined and open configurations.

Stabilized Ru[(H2O)6]3+ in Confined Spaces (MOFs and Zeolites) Catalyzes the Imination of Primary Alcohols under Atmospheric Conditions with Wide Scope

Imines are ubiquitous intermediates in organic synthesis, and the metal–mediated imination of alcohols is one of the most direct and simple methods for their synthesis. However, reported protocols lack compatibility with many other functional groups since basic supports/media, pure oxygen atmospheres, and/or released hydrogen gas are required during reaction. Here we show that, in contrast to previous metal-catalyzed methods, hexa-aqueous Ru(III) catalyzes the imination of primary alcohols with very wide functional group tolerance, at slightly acid pH and under low oxygen atmospheres. The inorganic metal complex can be supported and stabilized, integrally, within either faujasite-type zeolites (Y and X) or a metal organic framework (MOF), to give a reusable heterogeneous catalyst which provides an industrially viable process well below the flammability limit of alcohols and amines.

Chemical pathways of Nanoscale Zero-Valent Iron (NZVI) during its transformation in aqueous solutions

The current application of Nanoscale Zero-Valent Iron (NZVI) is subject to the countermeasure of water contamination that escalates with increasing population. Some of the NZVI advantages include; environmental friendliness, high reactivity and cost-effectiveness. NZVI was synthesized through the reduction of a ferric ion by sodium borohydride in anoxic medium and the resulting particles were characterized by the Transmission Electron Microscope with Energy-dispersive X-ray (TEM-EDX). The NZVI evolution and dissolution in water were examined through a series of batch experiments conducted in varying experimental conditions which include; pH, temperature, dosage, oxygen and interferences. The dissolution of iron was enhanced in the acidic pH due to the presence of H+ ions thus favoring release of hydrogen gas. More iron ions were present in the lowest temperature (5 °C) due to decreased crystallization and proton assisted dissolution. Furthermore, highest NZVI dosage (3 g/L) resulted in the highest iron ions concentrations in solution due to the increased number of nanoparticles hence providing surface-active sites. Ultimately, more iron ions were present in limited oxygen supply condition involving initial air saturation showed due to decreased crystallization and precipitation which were favored in continuous supply. These results are a useful guidance during real-life application of NZVI.

Metal Complexes with Zwitterionic Amino‐bis(methylcarboxyl) Group Expand Life‐Span of Aluminum Electrolyte Capacitor

AbstractThis paper investigates a new metal complex that expands the life‐span of an insulator thin‐film formed from anodically‐oxidized alumina in an aluminum electrolyte capacitor. The insulator thin‐film was generally unstable in an electrolytic water solution because of hydrate dissolution. However, in an electrolytic solution containing H2PO4– ions and the organic acid diethlenetriamine‐N,N,N',N',N̋,N̋‐pentaacetic acid (H5dtpa), the life‐span of the insulator thin‐film was remarkably expanded to more than 10000 h because the protective membrane on the anodic alumina electrode was stabilized. The stabilization effects of two complexes, [GaIII(H2dtpa)(H2O)] (1) and [InIII(Hdtpa)Na(H2O)3] (2), were investigated using leak current, 31P‐NMR, and ESI‐TOF‐mass measurements. In 1 only, the life‐span of the anodic alumina electrode expanded, while in 2, an electrical connection through the insulator thin‐film due to hydrate dissolution caused a rapid explosive release of hydrogen gas. The differences in these results were attributed to the free amino‐bis(methylcarboxyl) group in 1, which recognized H2PO4– to form a protective alumina membrane.

Hydrogen generation via hydrolysis of Mg2Si

A convenient, high-density and low-cost hydrogen supply technology is essential to hydrogen energy system by providing hydrogen to fuel cell component. Magnesium silicide (Mg2Si) can be a good hydrolysis candidate due to its low cost and ability of releasing hydrogen gas during hydrolysis process. However, previous studies have demonstrated that Mg2Si could easily produce large amount of silanes during hydrolysis reaction, which may cause serious problem of explosive danger when in contact with air. Here it is the first time that Mg2Si was used for generation of hydrogen by a simple and convenient one-step hydrolysis reaction. In this study, hydrolysis kinetics and mechanisms of Mg2Si in NH4Cl and NH4F solutions were investigated. The silanes could be almost completely turned into hydrogen by introduction of fluorine ion during the hydrolysis reaction of Mg2Si, leading to very low silanes content in the produced hydrogen. The kinetic studies indicated that when the concentration of the NH4F solution increased to 13.0%, the hydrogen generation rate and the reaction yield were improved significantly and reached the best performance, producing 466 mL g−1 H2 in 10 min and 616 mL g−1 H2 in 30 min at 25 °C. The activation energy was calculated to be 37.3 ± 0.8 kJ mol−1. Furthermore, the hydrogen yield and the hydrolysis rate of Mg2Si can be further improved by high-energy ball milling. After ball milling for 2 and 5 h, the hydrogen generation yield in 30 min increased to 698 and 771 mL g−1, respectively, and the activation energy was decreased to 23.9 ± 0.6 kJ mol−1 and 12.9 ± 0.1 kJ mol−1, respectively. The results revealed that NH4F can be a promising reagent for promoting the hydrolysis of Mg2Si for onsite hydrogen supply.

3D Assembly of Gold Nanoparticles As a Novel Catalyst for Hydrogen Generation Reaction from a Hydrogen Feedstock Material

With the limited supply of fossil fuels becoming more of a concern, there has been an increased focus in finding alternative sources of energy. One source of clean energy is hydrogen gas. Studies have been done examining the generation of hydrogen gas from water, which is an energy intensive process. There has been less effort in generating hydrogen gas from a solid feedstock, such as sodium borohydride. In the presence of water, sodium borohydride releases hydrogen gas slowly. In order to be used as an efficient source of energy, this reaction needs to be catalyzed so the reaction happens at a sufficient rate. One area of catalysis is the noble metals such as gold at the nanoscale. Using metal nanoparticles is a cost-effective way to use these metals as a catalyst, because much less of the bulk precursor is needed [1,2]. Without a support, the nanoparticles will not be as effective, so a 3D assembly of gold nanoparticles were synthesized and tested to determine its effectiveness as a catalyst [3]. The data show an increase in the efficiency of the generation of hydrogen gas with the addition of gold catalyst when compared to the un-catalyzed reaction. The reaction catalyzed by the gold assembly has a rate constant of 15.8 L mol-1 hr-1, compared to the un-catalyzed reaction which produced hydrogen at rate of 6.42 L mol-1 hr-1, and was determined to be a second order reaction. This catalyzed process produced 92% more moles of hydrogen gas than the un-catalyzed reaction in the same time period. References Abdel-Fattah T. M.; Wixtrom A. Catalytic Reduction of 4-Nitrophenol Using Nanoparticles on Carbon 2014, ECS J Solid State 3(4) M18-M20.Huff C, Dushatinski T, Abdel-Fattah TM. Gold nanoparticle/multi-walled carbon nanotube composite as novel catalyst for hydrogen evolution Int. J. Hydrogen Energy, 2017, DOI: https://doi.org/10.1016/j.ijhydene.2017.05.226Wen, Dan; Liu, Wei; Gold Aerogels: Three-Dimensional Assembly of Nanoparticles and Their Use as Electrocatalytic Interfaces. 2016, ACS Nano, 10(2), pp 2559 – 2567

Fabrication and characterization of nanostructured hydroxyapatite coating on Mg-based alloy by high-velocity oxygen fuel spraying

Magnesium alloys are currently being investigated in orthopedic applications due to their biodegradability and mechanical properties. However, sometimes these benefits are limited by their high corrosion rate in the physiological environment before healing of damaged bones. A large number of recent researches in this field have been dedicated to the control of magnesium corrosion rate by surface protection using new and advanced coatings. In this work, hydroxyapatite powders were coated on the anodized Mg-based alloy substrates by using high velocity oxy-fuel (HVOF) spraying. Increasing of the bioactivity and reduction of the released hydrogen gas during corrosion of the substrate were two main objects of this work. Phase formations were characterized by X-ray diffraction (XRD). It was found that around 96% of the phases formed were hydroxyapatite. The amounts of hydrogen gas released during magnesium corrosion tests in the simulated body fluid (SBF) were measured to evaluate the corrosion resistance of the coated samples. Hydroxyapatite (HA) coating reduced the hydrogen evolution from 100 per cm2 ml to about 15 per cm2 ml after 29 h of immersion.

Nitrogen-doped tungsten carbide nanoarray as an efficient bifunctional electrocatalyst for water splitting in acid

Tungsten carbide is one of the most promising electrocatalysts for the hydrogen evolution reaction, although it exhibits sluggish kinetics due to a strong tungsten-hydrogen bond. In addition, tungsten carbide’s catalytic activity toward the oxygen evolution reaction has yet to be reported. Here, we introduce a superaerophobic nitrogen-doped tungsten carbide nanoarray electrode exhibiting high stability and activity toward hydrogen evolution reaction as well as driving oxygen evolution efficiently in acid. Nitrogen-doping and nanoarray structure accelerate hydrogen gas release from the electrode, realizing a current density of −200 mA cm−2 at the potential of −190 mV vs. reversible hydrogen electrode, which manifest one of the best non-noble metal catalysts for hydrogen evolution reaction. Under acidic conditions (0.5 M sulfuric acid), water splitting catalyzed by nitrogen-doped tungsten carbide nanoarray starts from about 1.4 V, and outperforms most other water splitting catalysts.

Intratumoral high-payload delivery and acid-responsive release of H2 for efficient cancer therapy using the ammonia borane-loaded mesoporous silica nanomedicine

Hydrogen gas therapy as an emerging and promising therapy strategy has overwhelming advantages especially in bio-safety compared with other gas therapy routes, but is facing a great challenge in the long-term, highly-concentrated, deeply-seated disease site-specific administration of hydrogen gas, owing to its low solubility, high but aimless diffusibility in vivo. Herein, we propose to construct an ammonia borane-loaded mesoporous silica nanomedicine (AB@MSN) to realize the intratumoral high-payload delivery and in situ acid-controlled release of hydrogen gas. The constructed AB@MSN nanomedicine has a superhigh H2 loading capacity (130.6mg/g, more than 1370 times higher than that of the traditional H2@liposome nanomedicine) and a highly acid-responsive sustained release behavior, exhibiting high anticancer efficacies and high bio-safety in vitro and in vivo. The proposed nanomedicine-based strategy opens a new window for precision high-efficacy hydrogen therapy.