Methanolysis Of NaBH4 Research Articles

Synthesis of azo polymers and their catalytic performance in hydrogen production via NaBH4 methanolysis

The extensive use of fossil fuels has a profound impact on ecosystems and contributes to global warming through the emission of greenhouse gases. To mitigate these effects, alternative energy sources such as hydrogen are crucial. In this study, a green synthesis approach was used to prepare an azo cross-linked polymer containing 4-aminophenyl ether and resorcinol. The synthesized polymer was thoroughly characterized by FT-IR, BET, TGA, Zeta Potential and SEM-EDS analyses. The catalytic performance of the polymer in hydrogen production from NaBH4 via methanolysis was then investigated. Various parameters affecting hydrogen production, including catalyst and NaBH4 amounts, methanol volume and temperature, were systematically investigated to identify the optimum conditions. The polymer exhibited maximum hydrogen generation rate (HGR) of 12,619 mL H2 min⁻¹ gcat⁻¹ at 60 °C, respectively, with an activation energy of 24.22 kJ mol⁻¹. After optimization, the reusability of the polymer was evaluated over five cycles and the theoretical hydrogen generation rates were consistently achieved; however, the hydrogen generation time increased with each subsequent cycle. The primary objective of this research was to highlight novel azo linked polymers with potent catalytic activity in hydrogen generation, demonstrating the significant potential of the polymer to advance hydrogen generation. Ultimately, this study highlights the promising role of azo cross-linked polymers as effective catalysts for hydrogen production, offering new avenues and perspectives towards sustainable energy solutions.

Exploring the potential of surface-modified alginate beads for catalytic removal of environmental pollutants and hydrogen gas generation

In this study, hydrogel beads were fabricated using alginate (Algt) polymer containing dispersed nickel phthalocyanine (NTC) nanomaterial. The viscous solution of Algt and NTC was poured dropwise into a divalent Ca2+ ions, resulting in the formation of hydrogel beads known as NTC@Algt-BDs. The surface of the NTC@Algt-BDs was further modified by coating them with different types of metal ions, yielding metal-coated M+/NTC@Algt-BDs. The adsorbed metal ions i.e., Cu+2, Ag+, Ni+2, Co+2, and Fe+3 were subsequently reduced to zero-valent metal nanoparticles (M0) by NaBH4. The prepared beads were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Initially, M0/NTC@Algt-BDs were examined for the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Among them, Cu0/NTC@Algt-BDs catalyst exhibited the highest reduction rate and therefore, investigated for reduction of different nitrophenols (NPs) and dyes, including 2-nitrophenol (2-NP), 2,6-dinitrophenol (2,6-DNP), methyl orange (MO), potassium ferrocyanide (PFC), congo red (CR), and acridine orange (ArO). The highest reduction rates of 2.019 and 1.394 min−1 were observed for MO and 2-NP, respectively. Furthermore, the fabricated catalysts were employed for the efficient production of H2 gas by NaBH4 methanolysis. Among which the Ag0/NTC@Algt-BDs catalyst showed excellent catalytic production of H2 gas, exhibiting the lowest activation energy (Ea) of 25.169 kJ/mol at ambient temperature. Furthermore, the impact of NaBH4 amount, and catalyst dosage on the reduction of 2-NP and H2 gas production was conducted whereas the effect of temperature on methanolysis of NaBH4 for evolution of H2 gas was studied. The amount of H2 gas was confirmed by GC-TCD system. Additionally, the recyclability of the catalyst was investigated, as it garnered significant research interest.

Structure-performance relationship of SrTiO3/S@g-C3N4 nanocomposites for highly active hydrogen production via NaBH4 methanolysis

The catalytic performance of SrTiO3/S@g-C3N4 nanocomposite catalyst for hydrogen production from NaBH4 methanolysis was investigated. The X-ray diffraction (XRD), attenuated total reflectance (ATR) spectroscopy, and scanning electron microscopy (SEM) analyses revealed the structure of the nanocomposite catalyst. The XRD spectrum of SrTiO3/S@g-C3N4 showed the presence of both SrTiO3 and S@g-C3N4 phases. ATR spectroscopy analysis proved the interaction between SrTiO3 and g-C3N4 that facilitates electron-hole separation and charge transfer. The SEM images demonstrated that the SrTiO3/S@g-C3N4 sheets were broken up during growth. The surface area of SrTiO3/S@g-C3N4 was 195 m2/g, which is higher than that of pristine S@g-C3N4 (40 m2/g), while the BJH pore size of SrTiO3/S@g-C3N4 (1.6 nm) was lower than that of S@g-C3N4 (2.0 nm). The band gap of the nanocomposite catalyst was reduced from 2.71 to 2.67 eV after the incorporation of SrTiO3. The PL spectra showed a characteristic peak of S@g-C3N4 at 457 nm, which red-shifted with the addition of SrTiO3. The catalyst SrTiO3/S@g-C3N4 achieved a promising hydrogen production rate of 8537 mL/g.min and a reaction activation energy of 19.20 kJ/mol. These findings show promise for catalytic performance and high efficiency in hydrogen generation from NaBH4 methanolysis.

Superb ruthenium(ii) complex melody: Uncovering its hidden catalytic and biological properties

Aliphatic/aromatic nitrogen-substituted ligands have a very important role in ruthenium chemistry. Polydentate ligands with N-substituted pyridine rings are notable for their ability to easily modify the electronic and steric properties of ruthenium. In this study, the catalytic and biological activities of the [RuCl2(NNN)(CH3CN)] (NNN: 2,6-di(1H-pyrazol-3-yl)pyridine)) complex were examined for two different applications. Firstly, the superb Ru(II) complex was used to catalyze the methanolysis of NaBH4, and its initial rate was calculated as 69360 mLH2min−1gcat−1. Secondly, the biological activities of the superb Ru(II) complex were examined. Accordingly, it was determined that this homogeneous complex showed anti-microbial activity on all bacteria used in the study, among the Gram-positive bacteria used in the study, the best result belongs to the Bacillus cereus EMC 19 bacterium with 8 mm, while among the Gram-negative bacteria, the best zone diameter belongs to the Pseudomonas aeruginosa DSM 50071 bacterium with 5 mm. However, it was observed that zone diameters varied between 8 mm and 3 mm. Compared to the control group, it was determined that 0.25 mg/mL concentration had 94.87%, 0.5 mg/mL concentration 96.10%, 1 mg/mL concentration 96.50%, and 2 mg/mL concentration 97.09% cytotoxic activity on the SH-SY5Y cell line. it was determined that all doses of the superb Ru(II) complex used in the study showed anti-cancer activity, but the anticancer activity shown at low doses was statistically more significant at the p < 0.05 level.

Investigating the potential of ZrO2/MoO3 nanocomposites for efficient hydrogen generation through NaBH4 methanolysis

This work investigates the potential of ZrO2/MoO3 nanocomposites as catalysts for hydrogen production through NaBH4 methanolysis. The samples were prepared by controlled thermal calcination and characterized using various techniques like XRD, FTIR, Raman, SEM, and surface area BET analysis. Rietveld refinements verified the presence of the ZrO2 monoclinic phase with the space group P21/c in all samples and a second orthorhombic MoO3 phase with the space group Pnma. The average crystal size decreased from 44 to 40 nm. FTIR and Raman spectroscopy confirmed the successful preparation of ZrO2/MoO3 nanocomposites. SEM analysis showed ZrO2 particles and MoO3 nanoparticles adhered to the ZrO2 surface, potentially creating a rougher texture. The results confirmed the formation of ZrO2/MoO3 nanocomposites with increasing MoO3 content, leading to an increased surface area of 19–23 m2/g. The catalytic performance evaluation revealed that the sample containing 30 % MoO3 (ZM3) exhibited the highest hydrogen generation rate of 18,451 mL/g. min at 30 °C. The calculated activation energy for ZM3 was 18.78 kJ/mol, suggesting efficient hydrogen generation at moderate temperatures.

Robust and efficient hydrogen production performance using nitrogen- and phosphorus-doped microalgal carbon-based metal-free carbon composite

Carbon-based metal-free catalysts are attracting attention in different applications. However, these metal-free carbon materials do not have sufficient active sites, resulting in low catalytic activity. Therefore, modification of metal-free carbon materials with appropriate approaches is important. The simultaneous doping of different electronegative heteroatoms has a positive effect on catalytic performance due to the synergistic effect caused by the electronic interactions between different atoms compared to mono-doping. In this study, Spirulina platensis, a microalgae species that is easy to culture, was used as the carbon source. First, ammonia (NH3) and phosphoric acid (H3PO4) activation were used to modify the surface of activated carbon obtained from Spirulina platensis by KOH activation (SPAC). Thus, the SPAC surface is enriched with N(SPAC-N) and P atoms whose electronegativity is different from carbon. These modified carbon particles (SPAC-N-P) were used as a metal-free catalyst to increase the H2 production rate from NaBH4 methanolysis. XRD, TEM, TG/DTG, FTIR and XPS analyses were used for the characterization of the obtained catalysts. FTIR and XPS analyses showed successful incorporation of N, P and O atoms. HGR values of 5737, 6104 and 13,052 mL min−1gcat−1 by SPAC, SPAC-N and SPAC-N-P catalysts were obtained, respectively. There is a significant increase in the catalytic performance of the catalysts obtained with both NH3 and H3PO4 activations.

Scalable polycondensation approach for efficient Al/S@g-C3N4 hydrogen production catalyst

This article investigates the development of an efficient Al/S@g-C3N4 catalyst for hydrogen production through sodium borohydride (NaBH4) methanolysis. The catalyst was prepared using a facile and scalable polycondensation technique. The prepared catalyst was characterized extensively by XRD, FTIR, SEM, and surface area analyses. XRD and FTIR analysis showed a reduction in the interlayer distance between the S@g-C3N4 sheets with increasing Al content. The SEM images showed a rough and uneven surface of the nanosheets. The obtained values of Eg are 2.6, 2.4 and 2.5 eV for the samples doped with 0.0, 1.0 and 2.0 wt% of Al. Increased surface area (up to 92 m2/g) and slightly smaller mesopores (1.56 nm) observed with increasing Al doping up to 2.0 wt%. Significant enhancement in hydrogen generation rate with a maximum of 10,112 mL/g.min was achieved for 2.0 wt% Al. Low activation energy of 27.08 kJ/mol for the 2.0 wt% Al-doped catalyst. The catalyst demonstrated good stability after undergoing multiple NaBH4 methanolysis cycles.

Microwave-assisted sumac based biocatalyst synthesis for effective hydrogen production

Hydrogen (H2), a renewable energy source with a high energy density and a reputation for being environmentally benign, is being lauded for its potential in various future applications. In the present context, the catalytic methanolysis of sodium borohydride (NaBH4) is of considerable importance due to its provision of a pathway for the efficient production of hydrogen gas (H2). The main aim of this research attempt was to assess the viability of utilizing refuse defatted sumac seeds as an unusual precursor in microwave-assisted K2CO3 activation to produce a biocatalyst.The primary objective that motivated the synthesis of the biocatalyst was to facilitate the generation of hydrogen via the catalytic methanolysis of NaBH4. With the aim of developing a biocatalyst characterized by enhanced catalytic performance, we conducted an exhaustive investigation of a wide range of experimental parameters. The activation agent-to-sample ratio (IR), impregnation time, microwave power, and irradiation time were among these parameters.Significantly enhanced in catalytic activity, the biocatalyst produced under particular conditions achieved a peak hydrogen production efficiency of 10,941 mL min− 1 g.cat− 1. In particular, it was determined that the ideal conditions were as follows: 0.5 IR, 24 h of impregnation, 500 W of microwave power, and 10 min of irradiation. This novel strategy not only demonstrates the impressive potential of eco-friendly biocatalysts, but also positions them as a viable alternative material for the sustainable production of hydrogen via NaBH4 methanolysis.Three significant parameters contribute to the value and renewability of this study. The first is that waste is used as the primary material; the second is that the activator is less hazardous than other activators; and the third is that microwave activation is a green chemistry technique.Graphical

Activated carbon from waste fabrics as a catalyst for NaBH4 methanolysis

Hydrogen energy is attractive as a sustainable and clean energy. Chemical hydrides are being studied as a solution to the transportation and storage problems of hydrogen. Hydrogen can be produced by methanolysis reaction of sodium borohydride on a suitable catalyst. For this purpose, metal catalysts with high catalytic activity are generally used. Despite their high catalytic activity, the environmental impact and cost of metal-containing catalysts has led to increased interest in synthesizing metal-free catalysts. Activated carbons are advantageous materials for metal-free catalyst applications. In recent years, industrial wastes have attracted much attention for the synthesis of sustainable materials for activated carbon preparation. In this study, activated carbons are produced from waste fabrics by chemical activation method using H3PO4 and KOH chemical agents at different impregnation ratios (1:1, 2:1 and 3:1 % w:w) and different carbonization temperatures (400, 500, 600°C for H3PO4 and 600, 700, 800°C for KOH). These carbons are used as catalysts for hydrogen production and their catalytic activity is evaluated based on hydrogen generation rate (HGR). Therefore, the effect of different conditions used in the preparation of activated carbon was investigated to determine its impact on HGR. The increase in carbonization temperature decreases the HGR value of the catalyst. The increase in acid concentration increases the HGR value. The highest HGR value is obtained as 39600 mL/(min.gcat) with YKK1–800 activated carbon. Once the carbon with high activity is identified, the effect of reaction conditions such as NaBH4, methanol, catalyst amount, and temperature on HGR is investigated. The catalytic activities of the prepared activated carbons in NaBH4 electrooxidation are also investigated. YKK3–700 activated carbon shows the highest catalytic activity at 1.91 mA/cm2 at −0.63 V peak potential. This result is promising for the use of metal-free catalysts for direct sodium borohydride fuel cells.

The synthesis and characterization of carbon nanotube-supported CuBi catalyst for H2 production from NaBH4 methanolysis

In this study, carbon nanotube (CNT) supported bimetallic CuBi catalysts are synthesized by sodium borohydride (SBH, NaBH4) reduction method at different atomic molar ratios. X-ray diffraction (XRD), scanning electron microscopy and X-ray energy dispersion (SEM-EDX), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and temperature-programmed desorption (TPD) analytical techniques have been characterized for the synthesized catalysts. The effects of temperature and catalyst, methanol, and NaBH4 amounts on the initial hydrogen production rate (HGR) are investigated. The initial HGR of CuBi(80:20)/CNT catalyst is calculated as 37545.6 mL/min.gcat at 25 mg catalyst, 1.5% NaBH4, 10 mL methanol (metOH), and 60 °C temperature (optimum parameters). Furthermore, the activation energy (Ea) calculated from the Arrhenius equation is calculated as 34.72 kJ/mol. As a result, CuBi(80:20)/CNT catalyst is promising as a catalyst for NaBH4 methanolysis.

Hydrogen Generation from NaBH4 Methanolysis with Ru/AC Catalyst Synthesized by Microwave Reduction Method

Hydrogen Generation from NaBH4 Methanolysis with Ru/AC Catalyst Synthesized by Microwave Reduction Method

Preparation of chromium barium oxide catalysts for hydrogen evolution from sodium borohydride methanolysis

This paper describes the synthesis of Cr2O3, Cr1.7Ba0.3O3, and Cr1.4Ba0.6O3 nanoparticles as catalysts to enhance hydrogen evolution in sodium borohydride methanolysis. Various characterization techniques, comprising X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and others were utilized to characterize the prepared nanoparticles. The XRD analysis showed that the formed Cr2O3 exhibits a hexagonal crystal structure, with an estimated mean crystallite size of 24 nm. SEM micrographs showed nanoparticles with homogeneous distributions, exhibiting spherical or distorted spherical shapes. XPS analysis showed that all synthetic Cr2-xBaxO3 materials consist of Cr, O, and the presence of Ba for doped samples. The energy gap for pure Cr2O3 nanoparticles was determined to be 3.28 eV. Inclusion of Ba into the Cr2O3 nanostructure modified the band gap, resulting in values of 2.8 and 1.5 eV at 15 % and 30 % barium content. The hydrogen production rate from NaBH4 methanolysis for Cr2O3, Cr1.7Ba0.3O3, and Cr1.4Ba0.6O3 catalysts were 5984, 31176 and 11913 mL/g.min, respectively.

A High-Performance Cr2O3/CaCO3 Nanocomposite Catalyst for Rapid Hydrogen Generation from NaBH4.

This study aims to prepare new nanocomposites consisting of Cr2O3/CaCO3 as a catalyst for improved hydrogen production from NaBH4 methanolysis. The new nanocomposite possesses nanoparticles with the compositional formula Cr2-xCaxO3 (x = 0, 0.3, and 0.6). These samples were prepared using the sol-gel method, which comprises gelatin fuel. The structure of the new composites was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, environmental scanning electron microscopy (ESEM), and X-ray spectroscopy (XPS). The XRD data showed the rhombohedral crystallinity of the studied samples, and the average crystal size was 25 nm. The FTIR measurements represented the absorption bands of Cr2O3 and CaO. The ESEM micrographs of the Cr2O3 showed the spherical shape of the Cr2O3 nanoparticles. The XPS measurements proved the desired oxidation states of the Cr2-xCaxO3 nanoparticles. The optical band gap of Cr2O3 is 3.0 eV, and calcium doping causes a reduction to 2.5 and 1.3 eV at 15.0 and 30.0% doping ratios. The methanolysis of NaBH4 involved accelerated H2 production when using Cr2-xCaxO3 as a catalyst. Furthermore, the Cr1.7Ca0.3O3 catalyst had the highest hydrogen generation rate, with a value of 12,750 mL/g/min.

A Co-Fe/calcium phosphate catalyst improves the release of hydrogen from NaBH4

In this study, catalysts for hydrogen release via either hydrolysis or methanolysis were developed with a focus on solid-state hydrogen storage. The catalyst and supports were produced and deposited concurrently during an electrochemical process. The goals of this study include the electrochemical syntheses of Co-Fe/calcium-phosphate catalysts and an assessment of their performance in the release of hydrogen during the hydrolysis and methanolysis of NaBH4. Catalyst synthesis was accomplished via an electrochemical method that uses an electrochemical cell with two chambers separated by a bipolar membrane. The catalyst particles are formed in the cathode chamber. The duration of electrolysis influences the calcium-phosphate phase. The pH is low at the beginning of electrolysis; brushite is formed. Hydroxyapatite is produced when the electrolyte solution is electrolyzed for a longer time, and the pH of the solution becomes high. The pH of the solution impacts both the calcium phosphate phase and the amount of metal catalyst in a solution. A higher metal catalyst content (Co and Fe) makes the hydrogen release rate more significant. Hydrogen was released at a rate of 7173 mL per minute per gram of Fe-Co during the hydrolysis reaction of NaBH4. Between 81,000 and 98,000 mL of hydrogen was produced per gram of Fe-Co each minute during the methanolysis reaction with NaBH4.

Waste ceramic frit as novel catalyst triggering sodium borohydride methanolysis reaction

Hydrogen energy is remarkable as a clean and efficient energy source alternative to fossil fuels. In recent years, hydrogen production from methanolysis of borohydride species has been the subject of many studies. Catalysts are of critical importance in hydrogen production with NaBH4. The widespread and commercial availability of this process depends on the cost and sustainability of the catalysts. Due to the cost and environmental impacts of metal-containing or metal-doped support materials used as catalysts, low-cost, environmentally friendly, and high-activity catalysts are being investigated. For this purpose, waste ceramic frits were used as catalysts in the NaBH4 methanolysis reaction. The hydrogen generation rates (HGR) of 11 different frits were compared. The oxide contents of these frits were determined by XRF analysis, and the two frits with the highest HGR values were characterized by XRD and SEM-EDX methods. For the two frits identified by code F1 and F2, initial rates of 10,027 mL/min.gcat and 8839 mL/min.gcat were obtained at 30 °C with 0.05 g catalyst and 1.25 % NaBH4, respectively. The activation energies of F1 and F2 frits were calculated as 18.27 kJ/mol and 29.71 kJ/mol, respectively.

Processing of new efficient Cr1-xNaxO3 catalysts for sodium borohydride methanolysis

This study reports the development of a novel Cr1-xNaxO3 catalyst using a simple cost-effective method for hydrogen production from NaBH4 methanolysis. The properties of the nanocomposites were investigated by employing XRD, FTIR, SEM and XPS characterization techniques. The XRD diffraction peaks confirmed the rhombohedral crystal structure of Cr1.xNaxO3 nanoparticles. The average crystal size of these nanoparticles was found to be ranging from 25.0 to 20 nm. FTIR analysis showed the characteristic absorption bands of Cr1.xNaxO3 nanoparticles. The SEM images of Cr2O3 and Cr1.7Na0.3O3 demonstrated that the nanoparticles are irregular in shape, while Cr1.4Na0.6O3 has a porous surface texture. XPS spectra of Cr2O3, Cr1.7Na0.3O3 and Cr1.4Na0.6O3 confirmed the presence of chromium, oxygen, and sodium in the samples. The optical band gaps of Cr2O3 Cr1.7Na0.3O3 and Cr1.4Na0.6O3 nanoparticles were approximately 3.28 eV, 1.61 and 0.81 eV, respectively. Cr1.4Na0.6O3 exhibited the most significant level of activity in terms of hydrogen production of 19144 mL/g.min.

Natural lignin as efficient catalyst for H2 production from NaBH4 methanolysis at low temperature

Herein, natural lignin is used for the first time as a catalyst for the methanolysis of NaBH4. Lignin exhibits excellent catalytic activity for the methanolysis of NaBH4, and the HGR value is as high as 20425 mL H2·gcat−1·min−1 at room-temperature. It is still satisfactory even at − 20 ℃, with a HGR of 2182 mL H2·gcat−1·min−1, which is the highest value reported in the literature to date. In addition, the study of kinetic reaction orders for NaBH4 methanolysis catalyzed by lignin indicates that the catalytic methanolysis of NaBH4 obeys first-order kinetics with respect to both of NaBH4 concentration and catalyst dosage. The activation energy for the methanolysis catalysis by lignin is calculated to be 19.5 kJ·mol−1 at low temperature of − 20 ∼ 25 ℃. The lignin retain over 66% of the original catalytic activity at the end of fifth consecutive reuse, and the catalytic activity can be completely recovered through simple acid treatment.

Synthesis and characterization of magnesium zinc ferrite nanoparticles for catalytic hydrogen evolution

We have prepared Mg1-xZnxFe2O4 nanoparticles (x values varying from 0.0 to 0.8 by 0.2 increments) for use as catalysts for hydrogen production in the methanolysis of sodium borohydride (NaBH4). The catalytic performance of the Mg1-xZnxFe2O4 nanoparticles with different zinc content for hydrogen production were evaluated in the methanolysis of NaBH4 inside glass vessels. Different characterization techniques were used to analyse the prepared nanoparticles such as X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), Transmission Electron microscopy (TEM), and Scanning Transmission Electron microscopy STEM. The average size of Mg1-xZnxFe2O4 nanoparticles was 10 nm. The largest energy band gap value was 4.77 eV for MgFe2O4 nanoparticles, while the lowest value was 2.89 eV for Mg0.2Zn0.8Fe2O4 nanoparticles. Mg0.8Zn0.2Fe2O4 nanoparticles were proven as the catalysts with the highest hydrogeneration rate with a value of 15,957 mL min−1 g−1.

Facile oxygen doped heterojunction structured hybrid particles with γ-aluminium oxide dispersed over graphitic carbon nitride for dehydrogenation of sodium borohydride in methanol: Catalytic properties and mechanism

It is important to develop new metal-free catalysts that are both low-cost and environmentally friendly with high performance. Recently, heterojunction catalysts have been used more than single-component catalysts in catalytic reactions. The current study reports the facile production of a new environmental and green metal-free nanocatalyst by three stages including the synthesis of graphite carbon nitride (GCN) from urea, synthesis of GCN-γ-Al2O3 hybrid composite from GCN and aluminium oxide (γ-Al2O3), and synthesis of O-doped GCN-γ-Al2O3 from the interaction of hybrid GCN-γ-Al2O3 with nitric acid treatment. The obtained O-doped GCN-γ-Al2O3 hybrid material was used to catalyse the green and environmental H2 production(H2-P) from sodium borohydride (NaBH4) methanolysis for the first time. The chemical compositions and morphology structures of these heterojunction-structured hybrid catalysts were carefully characterized by SEM-EDS, XRD, FTIR, TEM, and XPS analyses, and the catalytic activities and reusability were systematically evaluated. The H2 generation rate (HGR) values of GCN, GCN-γ-Al2O3 and O doped GCN-γ-Al2O3 catalysts were found as 3486, 5310 and 10080 ml min-1 g-1, respectively. The activation energy (Ea) for the O-doped GCN-γ-Al2O3 catalyst was 35.12 kJ mol-1. Besides, the mechanism of the O-doped GCN-γ-Al2O3 catalyst in the NaBH4 methanolysis reaction(NaBH4-RM) was tried to be clarified.

Mechanistic insights into the deprotonation of methanol by facile synthesized 3D flower-like BiOX (X= Cl, Br, I) catalysts for rapid hydrogen generation from NaBH4 methanolysis: The ‘X’ factor

Bismuth oxyhalides (BiOX, X = Cl, Br, I) have been showing promising catalytic activity in various applications due to their electronic properties and unique layered structure. However, their catalytic potential for hydrogen generation from chemical hydrides is unrevealed. Herein, BiOX (X = Cl, Br, I) catalysts were prepared via a simple co-precipitation method. The physical and chemical characteristics of the as-prepared samples were then duly characterized using various techniques such as X-ray diffractometer spectroscopy (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Nitrogen adsorption-desorption, and Scanning electron microscope (SEM). The catalysts were then applied to NaBH4 methanolysis for the production of hydrogen. Among the BiOX catalysts, BiOCl exhibits excellent performance which is attributed to the highest electronegativity possessed by the Cl− halogens clinging onto the catalytic layers, simply overriding the substitution reactions. Subsequently, superior performances were depicted with rapid generation of hydrogen, High rate of hydrogen generation, HGR = 42,740 mL H2 g−1min−1, and calculated activation energy of Ea = 43.5 kJ/mol with stability for over 5 successive cycles. Withal, a plausible mechanism based on the exchange reactions promoted by the BiOX catalysts, which comprises interlacing [Bi2O2] slabs with double halogen slabs coupled with a strong ionic nature is illustrated in line with the experimental results.