Methanolysis Of NaBH4 Research Articles

Exceptional activity of hollow porphyrin frameworks-confined Ni nanoparticles for hydrogen production from NaBH4 methanolysis

Hollow framework materials have recently attracted broad interest owing to the multifarious superiorities, such as large surface area, adjustable pore structure, short transport distance, as well as high permeability. Herein, a nitrogen-rich hollow porphyrin framework (H-POF) was synthesized via SiO2 as hard template. Then, ultrafine Ni nanoparticles (NPs) were confined on the surface of H-POF via ultrasonic impregnation reduction method. The resultant Ni/H-POF catalyst shows an extraordinary catalytic performance toward the methanolysis of NaBH4, providing a hydrogen generation rate (HGR) value of 34720 mL·min−1·gmetal−1, which surpasses all heterogeneous catalysts ever reported with NaOH. Further experimental investigation confirms that the high catalytic activity can attributed to the large specific surface area and hollow structure of the support, small size of metal NPs, as well as the electron-donating effect of nitrogen atoms on metal NPs. Based on isotopic experiments, the breaking of OH bond in CH3OH is proved to be the rate-determining step (RDS) of NaBH4 methanolysis. This work provides valuable insights for rationally designing nitrogen-rich hollow framework materials for supporting ultrafine metal NPs, which will be used for the future energy-related applications.

Synthesis of waste eggshell-derived Au/Co/Zn/eggshell nanocomposites for efficient hydrogen production from NaBH4 methanolysis

Developing new pathways to transform biological wastes into value-added products is inevitable in order to mitigate environmental pollution and providing sustainability. Utilisation of eggshell as a substrate, a naturally abandoned organic-inorganic waste, was explored in this study. Herein, Au/Co/Zn/eggshell nanocomposites were synthesised by utilizing waste eggshell as substrate. At the experimental stage, different metal combinations namely unary, binary and ternary combination of Co, Zn and Au and different ratios ranges from %10 to %50 were tested. The catalytic activity of the synthesised materials were investigated in terms of hydrogen production from NaBH4 methanolysis. The catalyst fabricated with the addition of %40 Co + %40 Zn + 3 ppm Au showed the best catalytic activity and the reaction completion time was as low as 2.4 min. The results revealed that the fabricated catalyst showed a superior catalytic activity with the maximum hydrogen production rate of 4394.6 mL/min/gcat. The obtained maximum hydrogen production rate is highly compatible with the existing literature. Different NaBH4 concentrations and catalyst concentrations were also tested to investigate the fabricated catalyst behaviour. The fabricated catalyst was also experimented in different temperatures range from 30 °C to 60 °C to determine the Arrhenius kinetics and subsequently activation energy. The activation energy was calculated to be 13.25 kJ/mol. SEM-EDX, BET, XRD and FT-IR analysis were finally performed to determine morphological and structural characterization of the superior catalyst.

The catalytic activity of halloysite-supported Ru nanoparticles in the methanolysis of sodium borohydride for hydrogen production

Finding environmentally friendly new energy sources is very urgent for a sustainable and clean energy future. It is vital to reach clean energy sources such as hydrogen, which does not create a polluting by-product when burned with oxygen. In this study, for a livable clean universe, hydrogen production studies were carried out from sodium borohydride (NaBH4), which is a very good hydrogen storage material, in a methanolysis environment, over ruthenium nanoparticles (Ru (0) NPs) impregnated on halloysite (Hall) support material (Ru (0)@Hall) at room conditions. The catalytic performance of the newly synthesized Ru (0)@Hall nanocatalyst was tested in the NaBH4 methanolysis reaction for hydrogen production. It was determined that Ru (0)/Hall nanocatalyst showed excellent activity (initial turn-over frequency (TOFinitial) = 1882 h−1; 31.37 min−1) and reusability (at the end of the 5th cycle, it retained 90% of its initial activity) performance in the catalytic methanolysis of NaBH4. The analyzes of the Ru (0)@Hall nanocatalyst, both fresh and at the end of the 5th catalytic cycle, were made with advanced analytical methods (ICP-OES, XRD, XPS, SEM, HRTEM, TEM, TEM-EDX, BET) and the nature of the catalytic material was clarified. The results showed the homogeneous distribution of Ru (0) NPs on the Hall surface (mean size = 1.53 ± 0.17 nm). Kinetic studies of hydrogen production from catalytic methanolysis reaction of NaBH4 were performed based on nanocatalyst [Ru (0)@Hall], substrate [NaBH4] concentrations, and temperature (298–318 K). From the kinetic data, the kinetic parameters (Ea, ΔH≠, and ΔS≠) were calculated and the rate equation was determined.

Investigation of the performance of metal-free catalyst prepared from black tea and green tea waste for hydrogen production via methanolysis of sodium borohydride and optimization using response surface methodology

This study uses a waste biomass-based (green tea leaves and black tea leaves) catalyst for hydrogen production by methanolysis of sodium borohydride (NaBH4) in two ways. The Response Surface Methodology was used for parameter optimization of HGR using AAPC-WGTL and AAPC-WBTL at various parameters such as amounts of catalysts, NaBH4, and reaction temperature. In the case of the AAPC - WBTL catalyst, the highest HGR of 7676 ml min−1 g catalyst−1 was observed at 0.25 g NaBH4, 0.1 g catalyst, and 10 ml methanol (CH3OH) at 50 °C. For the AAPC - WGTL catalyst, the highest HGR of 9084.75 ml min−1g catalyst−1 was observed at 0.15 g NaBH4, 0.1 g catalyst, and 10 ml CH3OH at 50 °C. Moreover, the activation energies were found to be 47.06 kJ/mol and 47.89 kJ/mol for the AAPC-WBTL and AAPC-WGTL catalysts, respectively. FTIR, BET, SEM-EDS, HRTEM and XPS characterized the catalyst. The BET analysis shows that AAPC – WGTL and AAPC-WBTL catalysts have surface areas of 22.96 m2/g and 3.28 m2/g, pore diameters of 1.72 nm and 1.70 nm and pore volumes of 0.0047 cm3/g and 0.0331785 cm3/g respectively. Furthermore, Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) were performed. The AAPC-WGTL and AAPC-WBTL electrode shows 121 mF/cm2 and 63.77 mF/cm2 capacitance, respectively. Therefore, it can be said that WGTL and WBTL are both biomass capable of producing H2 using methanolysis of NaBH4.

Synthesis, characterization, and enhanced hydrogen generation from NaBH4 methanolysis of highly dispersed bimetallic PdNi nanoparticles supported on Vulcan carbon

In this presented work, the bimetallic palladium-nickel nanoparticles (PdNi NPs) supported by Vulcan carbon (VC) were synthesized by chemical method. The morphological structure of the synthesized PdNi@VC NPs was determined by ultraviolet-visible spectrum (UV–Vis), Fourier infrared spectrometry (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD) characterization performed. According to the characterization results obtained, the size of the NPs was found to be 8.523 ± 2.036 nm. Then, hydrogen production efficiencies were tested according to different temperatures, substrate, and catalyst concentrations. Finally, the reusability test was performed. According to the results obtained, the hydrogen average production efficiency of NPs was calculated as 84%. The activation energy (Ea), enthalpy (ΔH), and entropy (ΔS) values of the catalyst were found to be 54.2 kJ/mol, 51.7 kJ/mol, -134.5 J/mol.K, respectively. This study guides the new catalytic energy production studies to be carried out on nanotechnological platforms. These synthesized nanoparticles can be developed to be an efficient catalyst for hydrogen generation as an alternative energy source.

PDMA cryogel beads as a catalyst for hydrogen generation from NaBH4 alcoholysis

Poly[2-(dimethylamino)ethyl methacrylate] cryogel beads were prepared under cryogenic conditions via free radical polymerization and used as a catalyst in the production hydrogen (H2) from NaBH4 by alcoholysis. The efficiency of the catalyst was investigated in the range of 0–40 °C by both methanolysis and ethylene glycolysis reactions, and its reuse was tested. Accordingly, it was observed that the methanolysis reaction was faster than the ethylene glycolysis reaction. When the hydrogen generation rate (HGR) values between 0 and 40 °C were compared, it was concluded that the methanolysis reaction rate increased from 1550 to 4800 mL.min−1g−1 and the ethylene glycolysis reaction rate increased from 923 to 3551 mL.min−1g−1. In the alcoholysis reaction catalyzed by PDMA cryogel beads, the activation energy was calculated as 19.34 and 22.77 kJ.mol−1 for the methanolysis and ethylene glycolysis reactions, respectively. After six repetitions, the catalyst activity was calculated over 50% for NaBH4 methanolysis and ethylene glycolysis.

A novel hazelnutt bagasse based activated carbon as sodium borohydride methanolysis and electrooxidation catalyst

In this study, activated carbon is produced from defatted hazelnut bagasse at different activation conditions. The catalytic activities of activated carbons are evaluated for NaBH4 methanolysis and electrooxidation. These materials are characterized by N2 adsorption-desorption, FTIR, SEM-EDS and XPS and results show that these materials are prepared successfully. N2 adsorption-desorption results reveal that activated carbon (FH3-500) has the highest BET surface area as 548 m2/g, total pore volume as 0.367 cm3/g and micropore volume as 0.205 cm3/g. On the orher hand, as a result of hydrogen production studies, FH3-500 activated carbon catalyst has the highest initial hydrogen production rate compared to other materials. At 50 °C, this metal-free activated carbon catalyst has a high initial hydrogen production rate of 13591.20 mL/min.gcat, which is higher than literature values. Sodium borohydride electrooxidation measurements reveal that FH2-500 also has the highest electrocatalytic activity and stability. Hazelnut pulp-based activated carbons are firstly used as a metal-free catalyst in the methanolysis and electrooxidation of sodium borohydride, and its catalytic activity is good as a metal-free catalyst. The results show that the hazelnut pulp-based activated carbon catalyst is promising as a metal-free catalyst for the methanolysis and electrooxidation of sodium borohydride.

Chitosan hydrogel anchored phthalocyanine supported metal nanoparticles: Bifunctional catalysts for pollutants reduction and hydrogen production

Metal nanoparticles possess high catalytic activity in various organic transformation reactions. A catalyst must be recovered and re-used effectively and economically to lower the overall reaction cost. The recovery of a catalyst remains a challenge due to their extreme small size. In this research work, catalytic metal nanoparticles were synthesized on Zn-phthalocyanine (ZnPc) and chitosan hydrogel (CH) composite which acts as catalyst support. The ZnPc-CH support facilitate the easy recovery of the loaded metal nanoparticles. Metal nanoparticles (M0) based on Cu0, Ag0, Ni0, Co0 and Fe0 were decorated inside and on ZnPc-CH hydrogel surface. The developed M0@ZnPc-CH were utilized for the enhanced selective reduction of toxins and hydrogen production by methanolysis and hydrolysis of NaBH4. Effective catalytic reduction and hydrogen generation was successfully achieved with Co0@ZnPc-CH and ZnPc-CH. Under optimized conditions, Co0@ZnPc-CH showed complete reduction of 4-nitrophenol (4-NP) in 8.0 min with the fast 4-NP reduction kinetics (K = 0.611 min−1). Among the developed catalysts, ZnPc-CH showed fast H2 generation with high H2 generation rate (HGR = 4100 mLg−1min−1) under optimized conditions. Metal leaching from Co0@ZnPc-CH was negligible during recycling of the catalyst, suggesting that it could be implemented to 4-NP treatment from real water samples. Similarly, ZnPc-CH could produce same quantity of H2 throughout 4 continuous cycles of durability testing without any deactivation and leaching and ZnPc-CH showed high stability, indicating the effectiveness of the catalyst to be applied for H2 production on large scale.

Poly(2-aminoethyl methacrylate) based microgels catalyst system to be used in hydrolysis and methanolysis of NaBH4 for H2 generation

The poly(2-aminoethyl methacrylate) (p(AEM)) microgels were synthesized by microemulsion polymerization technique and used for in situ metal nanoparticle preparation to render as p(AEM)-M (M: Co or Ni) microgel composites and were used in p(AEM) based poly ionic liquid (PIL) microgels. Next, these p(AEM)) based microgel materials were used as catalysts for hydrogen (H2) production from both hydrolysis and methanolysis reactions of sodium borohydride (NaBH4). It was found that the catalytic hydrolysis of the NaBH4 reaction, catalyzed by p(AEM)-Co microgel composite was completed in 140 min, whereas the methanolysis of NaBH4 methanolysis catalyzed by the PIL of p(AEM)+Cl− microgels was completed in 5 min both with 250 ± 2 mL H2 production. Furthermore, p(AEM)-Co microgel composite catalysts maintained 80% catalytic activity after 5 consecutive uses in NaBH4 hydrolysis. On the other hand, p(AEM)+Cl− microgels were found to afford more than 50% catalytic activity even after 20 repetitive use in NaBH4 methanolysis due to superior regeneration ability. Moreover, activation energy values for p(AEM)-Co microgel composites catalyzed NaBH4 hydrolysis reaction were calculated as 38.9 kJ/mol in comparison to 37.3 kJ/mol activation energy of p(AEM)+Cl− microgel catalyzed methanolysis reaction.

Bacillus thuringiensis Based Ruthenium/Nickel Co-Doped Zinc as a Green Nanocatalyst: Enhanced Photocatalytic Activity, Mechanism, and Efficient H2 Production from Sodium Borohydride Methanolysis

Today, the development of green nanocatalysts is among the popular topics due to the need for energy production and the cleaning of organic pollutants. In this approach, Bacillus thuringiensis, a bacterium, was used as a biosupport of ruthenium/nickel co-doped zinc nanoparticles (btRNZn NPs) to release hydrogen from the methanolysis of sodium borohydride (NaBH4). In addition, their photocatalytic activity was reported against Methyl Orange (MO) organic dye. This study focused on the preparation, characterization, and catalytic and photocatalytic activity of the btRNZn biocatalyst for the release of hydrogen from the methanolysis of NaBH4 and removal of MO dye. According to TEM analysis, the average size of btRNZn NPs was found to be 11.78 nm; in addition, btRNZn NPs showed a photodegradation effect of 68.2% against MO dye at 90 min, and its photocatalytic mechanism was discussed. The effects of the catalyst, substrate, and temperature in the methanolysis reaction of NaBH4 in the presence of the catalyst were investigated extensively. The reaction kinetics was calculated, and TOF, activation energy, and enthalpy energy were measured as 2497.14 h–1, 14.89 kJ/mol, and 12.35 kJ/mol, respectively. It was observed that the methanolysis process is a first-order reaction based on the amount of the catalyst and substrate. This study aimed to synthesize a nanobiocatalyst (btRNZn NPs) by a biological method, and it will be used as a great photocatalyst to prevent wastewater pollution; also, it can be an excellent catalyst to produce hydrogen from NaBH4 methanolysis. The application of btRNZn NPs in solar photocatalysis to prevent wastewater pollution and to research it for energy production through hydrogen creation are both made clear by these studies.

Metal-free hybrid composite particles with phosphorus and oxygen-doped graphitic carbon nitride dispersed on kaolin for catalytic activity toward efficient hydrogen release

Here, hybrid kaolin-g-C3N4 heterostructure particles were fabricated by calcination in the first step, followed by hydrothermal phosphoric acid activation in the second step, and phosphorus (P) and oxygen (O) doped kaolin-g-C3N4 metal-free catalyst was synthesized. This hybrid metal-free catalyst was used for the first time for the production of effective hydrogen (H2) from sodium borohydride (NaBH4) methanolysis. The hydrogen generation rate (HGR) value of 5500 ml min−1g−1 was obtained with the P and O doped kaolin-g-C3N4 catalyst. The activation energy (Ea) of 31.90 kJ mol−1 by P and O doped kaolin-g-C3N4 for the production of H2 was obtained. The kaolin-g-C3N4 and P and O doped kaolin-g-C3N4 metal-free catalysts were systematically characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). Based on the results obtained, the mechanism of P and O-doped kaolin-g-C3N4 catalyst on H2 production from NaBH4 methanolysis was also proposed.

Highly active hydrogen generation from sodium borohydride methanolysis and ethylene glycolysis reactions using protonated chitosan-zeolite hybrid metal-free particles

Herein, the synthesis of low-cost, non-toxic and recyclable protonated chitosan-zeolite hybrid metal-free catalysts was carried out. The metal-free hybrid catalysts were used for the first time for efficient H2 production from NaBH4 methanolysis and ethylene glycolysis. The prepared chitosan-zeolite-H composite was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-Ray analyser (EDS), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and X-ray photoelectron spectroscopy (XPS) analyses. The different chitosan/zeolite ratios and different calcination temperatures, the effect of temperature and NaBH4 amount and reusability parameters were investigated. Also, the possible mechanism of H2 formation in methanol and ethylene glycol with chitosan-zeolite-H is discussed. HGR values of NaBH4 (0.25 g) methanolysis and ethylene glycolysis were 17,500 and 10,428 ml min−1g−1, respectively. Ea values obtained for the NaBH4 methanolysis and ethylene glycolysis were found to be 37.29 kJ mol−1 and 50.00 kJ mol−1, respectively.

Synergistic effect of Pd-Co3O4 nanoparticles supported on coffee-derived sulfur, nitrogen-codoped hierarchical porous carbon for efficient methanolysis of NaBH4

Sulfur, nitrogen-codoped (SN-doped) highly porous carbon nanostructures (CNSs) are established as efficient components for hydrogen generation applications. Waste coffee grounds are carbonized in situ and activated with KOH to produce hierarchically SN doped porous carbon nanostructures with a large specific surface area of 2320 m2 g−1. The amorphous and highly active Pd-Co3O4 nanoparticles (NPs) are anchored onto an SN-codoped carbon nanosheet prepared via a simple hydrothermal reaction. An effective method for optimization of the Pd-Co3O4/SN-CNS-600 catalytic efficiency for NaBH4 methanolysis using sodium sulfide as a precursor or combination of sulfur-containing salts as a raw material is proposed. The Pd-Co3O4/SN-CNS-600 catalyst exhibits an excellent catalytic activity for NaBH4 catalytic methanolysis at room temperature, with a high hydrogen generation rate of 20158 mL H2 min−1 gcat−1. The methanolysis reaction activation energy in an aqueous NaBH4 solution is approximately 14.52 kJ/mol. The excellent Pd-Co3O4/SN-CNS-600 catalytic activity is attributed to the small size and amorphous state of Pd-Co3O4 NPs, good synergistic interaction between Pd-Co3O4 NPs and SN-CNS with a large specific surface area, and abundant defects. Highly efficient, inexpensive, and environment-friendly catalysts are successfully developed for hydrogen generation.

Catalytic activites of a biomaterial (sumac) catalyst in sodium borohyride methanolysis reactions

Biomass waste (sumac) in particular, is an excellent starting point for preparing carbon materials since it is abundant, inexpensive, environmentally beneficial, and renewable. Therefore, the aim of the present study is defatted sumac (DS)- hydrochloric acid (HCl)- cobalt (Co) (DS-HCl-Co) catalyst (it will be used as a catalyst for the first time) in the presence of low activation energy and high hydrogen production rate (HPR). The effect of different parameters such as amount of catalyst, concentration of NaBH4 and temperature on HPR value obtained as a result of NaBH4 methanolysis in the presence of DS-HCl-Co catalyst have been investigated. The synthesized catalysts are named DS-HCl (pure) and DS-HCl-Co (supported). While the HPR value (mL*gcat−1 *min−1) obtained as a result of the hydrolysis experiments carried out is 3516.16 for the DS-HCl catalyst, it is 8298.5 for the DS-HCl-Co catalyst. Thus, it should be noted that the HPR value increases approximately 2.36 times in the presence of support material. Our other motivation in the current study is to have low activation energy, which is an important factor that increases catalytic activity. Using the Arrhenius equation, the activation energy for the DS-HCl-Co catalyst is calculated as 31.67 kJ/mol and this value is lower than some reported values ​​when compared to the literature.As a result, it can be said that the DS-HCl-Co catalyst is a unique, inexpensive, and ideal catalyst with high activity values ​​for hydrogen production from alkali hydrides.

Efficient hydrogen generation from the NaBH4 methanolysis by waste material: banana peel

Efficient hydrogen generation from the NaBH4 methanolysis by waste material: banana peel

Poly (acrylic acid)/polysaccharides IPN derived metal free catalyst for rapid hydrogen generation via NaBH4 methanolysis

Polymeric catalysts have displayed great performance for catalytic hydrogen generation. However, the reported metal free polymeric catalysts for NaBH4 methanolysis are mainly limited to coating strategy where the catalytic activity fade after few cycles. Herein, we report an interpenetrating polymer network (IPN) strategy for rapid and highly recyclable NaBH4 catalytic methanolysis to produce hydrogen (H2) gas. In this study, we prepared poly(acrylic acid)/polysaccharide IPN via Pickering tempted polymerization. The hydrogen generation performance was studied employing different parameters where maximum HGR of 8182 mL H2 min−1 g−1 of CAP. The activation energy Ea, enthalpy and entropy were calculated to be 62.99 kJ mol−1, 32.25 kJ mol and −130.92 J mol K−1, respectively. Above all, CAP kept cyclic performance to 100% even at the 7th cycle. We confirmed the reproducibility of approach with other natural polysaccharides. This was due to strong chain entanglement of IPN synthesis which forces the active sites to stay in place during cyclic catalysis reaction. Thus, the IPN strategy ensures longer catalyst life for catalytic methanolysis of NaBH4 for H2 generation.

Efficient reduction of organic pollutants and H2 generation using bimetallic nanoparticles coated alginate hydrogel beads

Here, a simple method is used for the preparation of calcium alginate-activated carbon composite beads (Alg-ACBDs). These beads were introduced into different metal salt solutions for decoration with single metal nanoparticle (M0) and double metal nanoparticles (M0-M0). The prepared M0/Alg-ACBDs catalysts, such as, Cu0/Alg-ACBDs, Ag0/Alg-ACBDs, Fe0/Alg-ACBDs, Cu0–Ag0/Alg-ACBDs, and Fe0–Cu0/Alg-ACBDs were evaluated against NaBH4 methanolysis. In addition, different surfactants, such as, brij-56, pluronic F-127, and urea (Co(NH2)2), different amount of NaBH4, catalyst, and temperature effect was also investigated for higher H2 generation from NaBH4 methanolysis. Similarly, the synthesized catalysts were used for the reduction of different nitrophenols (NPs) and dyes. The Fe0–Cu0/Alg-ACBDs catalyst efficiently catalyzed the reduction reaction of 4-NP and methyl orange (MO) and both were studied in detail. The corresponding reduction rate of 4-NP and MO was observed as 1.829 and 1.163 min−1, respectively. Moreover, the recyclability of the catalyst was investigated for 4-NP and H2 generation, where no decrease in the reduction percentage of 4-NP was recorded, while reduction in their catalytic rates was observed.

Efficient and durable H2 production from NaBH4 methanolysis using N doped hybrid g-C3N4-SiO2 composites with ammonia as a nitrogen source

In this study, a hybrid g-C3N4-SiO2-N composite was successfully produced in three stages by calcination and hydrothermal methods. The g-C3N4-based composite catalyst obtained by both N-doping and SiO2 addition was used in H2 production from NaBH4 methanolysis for the first time. In the NaBH4 methanolysis reaction, the electron-rich and electron-deficient surface regions formed on this catalyst surface with modifications made the electron transfer more efficient and significantly improved the catalytic performance. The maximum HGR was found to be 11400 mL min−1 g−1 at a concentration of 0.25 g NaBH4. The obtained HGR value shows that the g-C3N4-SiO2-N catalyst obtained in three steps has achieved its purpose. The activation energy (Ea) was calculated as 33.2 kJ mol−1. g-C3N4-SiO2-N demonstrated good durability, retaining 71% of the initial catalytic activity after five consecutive experiments.

G-C3N4 particles with boron and oxygen dopants/carbon vacancies for efficient dehydrogenation in sodium borohydride methanolysis

In the study, metal-free boron and oxygen incorporated graphitic carbon nitride (B and O doped g-C3N4) with carbon vacancy was successfully prepared and applied as a catalyst to the dehydrogenation of sodium borohydride (NaBH4) in methanol for the first time. The hydrogen generation rate (HGR) value was found to be 11,600 mL min−1g−1 by NaBH4 of 2.5%. This is 2.53 times higher than the g-C3N4 catalyst without the addition of B and O. The obtained activation energy was 25.46 kJ mol−1. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), energy dispersive X-Ray analyser (EDX), Transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) analyses for characterization were performed. A possible mechanism of H2 production from the reaction using metal-free B and O doped g-C3N4 catalyst with carbon vacancy has been proposed. This study showed that g-C3N4 and its composites with doping atoms can be used effectively in H2 production by NaBH4 methanolysis.

Metallic nanoparticles decorated chitosan hydrogel wrapped pencil graphite: Effective catalyst for reduction of water pollutants and hydrogen production

Chitosan hydrogel entrapped pencil graphite composite (CH/PG) was prepared with the strategy to confine metal nanoparticles (M0) in hydrogel. CH/PG could robustly anchor and remarkably disperse M0 on the surface and inside hydrogel. M0 like copper (Cu0@CH/PG), silver (Ag0@CH/PG), nickel (Ni0@CH/PG), cobalt (Co0@CH/PG) and iron (Fe0@CH/PG) were anchored in CH/PG hydrogel. All the prepared hydrogels were tested and displayed outstanding performance in reduction of water pollutants and hydrogen (H2) generation. The catalytic reduction of 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), 2,6-dinitrophenol (2,6-DNP), methylene blue (MB), congo red (CR), methyl orange (MO), acridine orange (ArO), and potassium ferricynide (K3[Fe(CN)6]) were investigated using CH/PG and M0@CH/PG in the presence of NaBH4. In addition, CH/PG and M0@CH/PG were examined in hydrogen generation by methanolysis and hydrolysis of NaBH4. Among all the catalysts, CH/PG was more efficient in catalytic H2 generation (HGR = 2050 mLg–1min–1) while Ag0@CH/PG was more efficient in catalytic reduction of water contaminants. The reduction rate of Ag0@CH/PG was fast for 4-NP and reduced completely within 6.0 min with rate constant of 0.845 min–1. The impacts of different parameters like NaBH4 concentration, catalyst dosage, pollutant concentration, and temperature were precisely examined. Moreover, the recyclability of the catalyst was investigated up to three times, where slight decrease in reduction time was noted.