Catalytic Hydrogen Generation Research Articles

Amine-rich cyclotriphosphazene (P3N3) nano-cages for enhanced and selective Au(III) and Pd(II) recovery and hydrogen generation: Waste-to-resource tactics

Designing a new material for precious metals (PMs) recovery is of ultimate significance in the quest to explore highly efficient, selective, and stable adsorbents for a sustainable economy and green environment. Herein, novel amine-rich cyclotriphosphazene poly(tetrakis(4-aminophenyl)methane-co-cylotriphosphazene)- porous nano-cages (PTC-PNC) and microspheres (PTC-MS) were synthesized for adsorption and selective recovery of Au(III) and Pd(II) in aqueous solution. A combination of the abundant amine groups and the cage-like porous morphology of PTC-PNC makes it an ideal absorbent for recovery of the Au(III) (1592 mg g−1, pH 1.0, 60 oC) and Pd(II) (1372 mg g−1, pH 1.0, 60 oC) with high selectivity which was slightly decreased up to 8-11% even in the presence of 13 co-existing metals ions while an ultra-high recovery of 99% was obtained. The unique cage-like morphology of the PTC-PNC guarantees a fast adsorption equilibrium while the adsorption isotherm specifies a pseudo-second-order kinetic behavior and Langmuir isotherm. Amine groups were the most energetically favorable sites for the capturing and chelating of Au(III) and Pd(II) ions followed by their partial reduction to Au0 and Pd0. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron spectroscopy (HRTEM) analysis were employed to explore interactions and reduction mechanisms during the adsorption process. Adopting the waste-to-resource approach, after Au(III) and Pd(II) recovery, these adsorbents were applied for catalytic hydrogen generation from ammonia borane (AB) hydrolysis. Due to its favorable electronic structure, the PTC-PNC@Pd exhibited a higher hydrogen generation than PTC-PNC@Au. The as-synthesized PTC-PNC could be employed as a promising material for other MPs' selective recovery and green energy generation applications.

Catalytic Hydrogen Generation through Ammonia Borane Hydrolysis Using Metal–Organic Framework via O–H Bond Activation

Catalytic Hydrogen Generation through Ammonia Borane Hydrolysis Using Metal–Organic Framework via O–H Bond Activation

Spin-cross interface-inducing ultra-high catalytic activity in Co(OH)xPy-MXene toward alkali-free liquid hydrogen generation

Proclaiming the interfacial active sites of non-noble metals on supported catalysts is a paramount topic. Herein, a spin-cross interface (Co(OH)xPy (x/y=3.2)) in the intimate region between Co(OH)2 and CoP is designed by in situ hydroxylation and P-inducing strategy. An ultra-high catalytic hydrogen generation activity with a turnover frequency of 1640 min−1 is achieved for hydrolysis of ammonia borane (NH3BH3). Both experimental observations and computational simulations reveal that the spin-cross interface dramatically reduces the energy barriers for the dissociation of reactant molecules (NH3BH3 and H2O) to expedite the catalytic activity. The coexistence of active interface and MXene create the ensembles of Co atoms coordinated by OH and P. The construction of active sites of Co(OH)xPy simultaneously boosts the adsorption and dissociation of H2O and NH3BH3 molecules. This research provides new paradigm for the rational design of spin-induced catalysts in the future energy system depending on the activation of multi-molecules.

Hydrogen generation based on a gel-like formate system with a palladium catalyst

Catalytic formate decomposition under mild conditions is a promising strategy for hydrogen production as an efficient hydrogen carrier. Most of previous studies performed formate decomposition for hydrogen generation in liquid phase or using formate as a promoter for formic acid decomposition, which exhibits relatively low hydrogen energy density by mass. Here, we reported a gel-like formate system for catalytic hydrogen generation under mild conditions. A H2 yield of 100% with hydrogen energy density by weight of 2.38 wt% was achieved, and the palladium catalyst shows high stability and recyclability for KCOOH gel decomposition. Moreover, the constructed gel-like formate filled in an aluminum cylinder could continuously and steadily supply hydrogen to a 12V/35W fuel cell to drive a LED display. This work may provide a new thought for safe hydrogen storage and production system for hydrogen energy usage in the future.

Hydrogen production on CoFe, CoFeMn and CoFeMo coatings deposited on Ni foam via electroless metal plating


 
 
 
 In this study, the catalytic hydrogen generation was evaluated on the cobalt–iron (CoFe), cobalt–iron–manganese (CoFeMn) and cobalt–ironmolybdenum (CoFeMo) coatings deposited on the Ni foam substrate using the electroless metal plating method and morpholine borane as the reducing agent. The characterisation of the surface morphology, structure and composition of resulted coatings was done using scanning electron microscopy (SEM) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The catalytic activity of the prepared CoFe/Ni, CoFeMn/Ni and CoFeMo/Ni catalysts was investigated for hydrogen generation from an alkaline sodium borohydride (NaBH4) solution at different temperatures. It was found that the hydrogen generation rate of ca. 5.2, 7.8 and 11.7 L min–1 g–1 was achieved by using the CoFe/ Ni, CoFeMo/Ni and CoFeMn/Ni coatings, respectively, at 343 K. Among the investigated catalysts, CoFeMn/Ni exhibits the lowest activation energy of 62.4 kJ mol–1 and the highest HGR of 11.7 L min–1 g–1 at 343 K.
 
 
 

3D printing Al porous metamaterials with triply periodic minimal surfaces (TPMS) for hydrogen generation from Al-water reaction

Porous metamaterials with three-dimensional periodic minimal surfaces provide new inspirations to develop catalytic hydrogen generation materials owing to their excellent mass transfer. Herein, ten kinds of Al porous metamaterials with triply periodic minimal surfaces (TPMS) were prepared by selective laser melting (SLM) for hydrogen generation from Al–H2O reaction. The structures of TPMS type Al materials significantly affect their hydrogen generation performance, and the increased reaction area and liquid flow rate of TPMS structure can effectively improve the galvanical replacement reaction and rapidly form a Ni/Al battery, thus accelerating the hydrogen generation. Compared to conventional aluminum powder, the obtained Diamond type Al porous metamaterial exhibit short induction period, high hydrogen generation yield (81.4 % after 2 h reaction) and high hydrogen generation rate (468 mL-H2·min−1·gAl−1), easy activation of surface passivation film, good structural stability and convenience to recycle the materials after use. This work highlights a simple, low-cost and optional porous structure design strategy that can be applied in the field of safe and efficient catalytic hydrogen generation.

Hydrogen catalytic performance of hybrid Fe3O4/FeS2/g-C3N4 nanocomposite structures

In this work, Fe3O4/FeS2/g-C3N4 nanocomposites were developed for catalytic hydrogen generation from sodium borohydride. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and environmental scanning electron microscopy (ESEM) were used to analyze these nanocomposites. The XRD diffraction peaks of Fe3O4 and FeS2 cubic phase showed an average crystal size of calculation of 15 and 20 nm. ESEM micrographs showed a 2D broken up sheet structure having more edge sites. The BET surface areas for S@g-C3N4, 1.0, 2.0, and 3.0 wt% Fe3O4/FeS2 were 40, 109, 137 and 162 m2/g, respectively. Even though Fe3O4/FeS2 were incorporated into the nanosheet, the pore size was increased from 2.0 to 2.15 nm. S@g-C3N4 has an average band gap of 2.60 eV that decreased to 2.30, 2.21 and 2.18 eV at 1.0, 2.0 and 3.0 wt% of FeS2. In addition, Fe3O4/FeS2/g-C3N4 nanosheets showed an emission band at 460 nm. Moreover, the intensity of this band decreased as the content of Fe3O4/FeS2 reached 3.0 wt%. The rate of hydrogen production is accelerated as the percentage of Fe3O4/FeS2 increased from 1.0 to 3.0 wt%. The sample 3.0 wt% Fe3O4/FeS2 showed the best rate of hydrogen production (8480 mL/g·min).

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.

Temperature of photoanode for photoelectrochemical water oxidation

Solar-light-driven photoelectrochemical that can utilise water for high-performance artificial photosynthesis for low-cost green hydrogen fuel production. However, the interaction of photoanode with water is crucial to its heterogeneous water oxidation for sustainable fuel production for the replacement of fossil fuels. Here, we report experiment investigations of photoelectrode with temperature for solar energy conversion. These measurements revealed that a rise in temperature affects the catalytic generation of hydrogen in three routes, viz., minimising the required energy for water splitting, reducing bandgap energy and mitigating the resistance at the interface.

In Situ Polycondensation Synthesis of NiS-g-C3N4 Nanocomposites for Catalytic Hydrogen Generation from NaBH4.

The nanocomposites of S@g-C3N4 and NiS-g-C3N4 were synthesized for catalytic hydrogen production from the methanolysis of sodium borohydride (NaBH4). Several experimental methods were applied to characterize these nanocomposites such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and environmental scanning electron microscopy (ESEM). The calculation of NiS crystallites revealed an average size of 8.0 nm. The ESEM and TEM images of S@g-C3N4 showed a 2D sheet structure and NiS-g-C3N4 nanocomposites showed the sheet materials that were broken up during the growth process, revealing more edge sites. The surface areas were 40, 50, 62, and 90 m2/g for S@g-C3N4, 0.5 wt.% NiS, 1.0 wt.% NiS, and 1.5 wt.% NiS, respectively. The pore volume of S@g-C3N4 was 0.18 cm3, which was reduced to 0.11 cm3 in 1.5 wt.% NiS owing to the incorporation of NiS particles into the nanosheet. We found that the in situ polycondensation preparation of S@g-C3N4 and NiS-g-C3N4 nanocomposites increased the porosity of the composites. The average values of the optical energy gap for S@g-C3N4 were 2.60 eV and decreased to 2.50, 2.40, and 2.30 eV as the NiS concentration increased from 0.5 to 1.5 wt.%. All NiS-g-C3N4 nanocomposite catalysts had an emission band that was visible in the 410-540 nm range and the intensity of this peak decreased as the NiS concentration increased from 0.5 to 1.5 wt.%. The hydrogen generation rates increased with increasing content of NiS nanosheet. Moreover, the sample 1.5 wt.% NiS showed the highest production rate of 8654 mL/g·min due to the homogeneous surface organization.

Interfacial active sites on Co-Co2C@carbon heterostructure for enhanced catalytic hydrogen generation

Interfacial active sites on Co-Co2C@carbon heterostructure for enhanced catalytic hydrogen generation

Structurally-New Hexadecanuclear Ni-Containing Silicotungstate with Catalytic Hydrogen Generation Activity

A structurally-new, carbon-free hexadecanuclear Ni-containing silicotungstate, [Ni16(H2O)15(OH)9(PO4)4(SiW9O34)3]19-, has been facilely synthesized using a one-pot, solution-based synthetic method systematically characterized by single-crystal X-ray diffraction and several other techniques. The resulting complex works as a noble-metal-free catalyst for visible-light-driven catalytic generation of hydrogen, by coupling with a [Ir(coumarin)2(dtbbpy)][PF6] photosensitizer and a triethanolamine (TEOA) sacrificial electron donor. Under minimally optimized conditions, a turnover number (TON) of 842 was achieved for TBA-Ni16P4(SiW9)3-catalyzed hydrogen evolution system. The structural stability of TBA-Ni16P4(SiW9)3 catalyst under photocatalytic conditions was evaluated by the mercury-poisoning test, FT-IR, and DLS measurements. The photocatalytic mechanism was elucidated by both time-solved luminescence decay and static emission quenching measurements.

Efficient catalytic hydrogen generation from formic acid dehydrogenation on ultrafine PdAu nanoparticles supported on modified carbon derived from rice straw

Formic acid (FA) dehydrogenation at ambient conditions is a promising route for hydrogen (H2) generation but still suffers from low activity and selectivity. Here, potassium hydroxide (KOH) and 3-aminopropyl triethoxysilane (APTES) modified porous carbon derived from the pyrolysis of rice straw (RSNPC) offers an effective support to promote the formation of ultrafine PdAu nanoparticles (NPs). Benefiting from the small sizes of PdAu NPs, the Pd0.7Au0.3/RSNPC catalyst exhibits excellent catalytic performance for FA dehydrogenation reaction with a high turnover frequency (TOF) of 6794.3 mol H2 mol catalyst−1 h−1 at ambient conditions, outperforming most of reported catalysts for FA dehydrogenation under similar conditions.

Highly effective palladium nanocatalyst supported in polymeric networks for the catalytic hydrogen generation from borane‐morpholine complex

AbstractThis study describes the synthesis of Pd0 nanoparticles supported in hydrogel networks (SPVI@Pd) and their catalytic activity for the borane‐morpholine complex (MB) hydrolysis reaction. In this respect, while our study is one of the limited number of studies reported for the catalytic hydrolysis of MB, it is the first study in which Pd0 nanoparticles supported in hydrogel networks were used in the catalytic hydrolysis of MB. The synthesized Pd0 nanoparticles were characterized using structural and morphological characterization techniques and as a result of these analyses, the sizes of Pd0 nanoparticles were determined average as 7.01±1.90 nm. The Ea value and the turnover frequency (TOF) value at 303 K for the SPVI@Pd3.0 catalyzed MB hydrolysis reaction were determined as 49.46 kJ/mol and 187.74 molH2 ⋅ molPd−1 ⋅ h−1. It was also observed that the SPVI@Pd3.0 catalyst had good catalytic activity even after eight cycles.

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.

Solar-driven multifunctional Au/TiO2@PCM towards bio-glycerol photothermal reforming hydrogen production and thermal storage

Photocatalytic hydrogen production and thermal storage are effective ways to convert solar energy into storable chemical energy and thermal energy, but they only respond to specific spectrum. In order to improve the energy conversion and storage efficiency of solar energy in the solar spectrum, hydrothermal and photo-deposition method were employed to synthesized photothermal catalyst while and Au/TiO2@PCM composite microcapsules were fabricated by electrostatic adsorption self-assembly methods. Micro-morphologies and structures were detailed characterized by SEM, XRD, UV-Vis, etc. As calculated from the DSC results for effective, enthalpy value, the loading rates of Au/TiO2 shell for the microcapsule were 12.6% and 15.4% corresponding to rod-shaped and sheet-shaped samples. To test their catalytic performance, the samples were dispersed in the same concentration of glycerol solution, and showed that the light to hydrogen efficiencies were 11.4‰ and 5.0‰ for ATR@PCM and ATF@PCM, respectively with the increasement of 53.8% and 56.1% comparing to their corresponding catalyst nanoparticle suspensions. Photo-thermal conversion efficiencies of ATR@PCM and ATF@PCM were 62.74% and 53.32% after 60 min-irradiations, and they were 48.22% and 25.96% higher than that of Me-PCM. Therefore, it was confirmed that the composite phase change microcapsules prepared in this study have the dual functions of energy storage and photothermal catalysis. Higher solar light to hydrogen energy conversion efficiency may be attained in future study if the stored thermal energy can be successfully employed to activate organic components for helping catalytic hydrogen generation.

Atomic-bridge structure in B-Co-P dual-active sites on boron nitride nanosheets for catalytic hydrogen generation

Engineering the adsorption and dissociation of molecules on dual-active sites at interface is an integral constituent for rational design of high-efficient catalysts. Herein, we describe a unique atomic-bridge structure in B-Co-P (namely Co-B and Co-P) dual-active sites on boron nitride nanosheets to stimulate activity toward borohydride hydrolysis. The formation of atomic-bridge structure in B-Co-P dual-active sites is contributed to the Local P-inducing Strategy (LPiS). The catalyst exhibits superior kinetics (turnover frequency of 37 min−1) with favorable stability during ammonia borane hydrolysis. Both experimental investigation and theoretical calculations reveal the key effects of atomic-bridge structure in B-Co-P interfacial dual-active sites on tailoring the electron density of Co species and reducing the energy barrier of reaction between ammonia borane and water molecules. This discovery is anticipated to furnish an impactful strategy to rationally design novel performance-oriented advanced catalysts for heterogeneous catalysis.

Prediction of Catalytic Hydrogen Generation by Water–Gas Shift Reaction Using a Neural Network Approach

Prediction of Catalytic Hydrogen Generation by Water–Gas Shift Reaction Using a Neural Network Approach

Hierarchical porous cobalt/carbon hybrid anchored Ru-catalyzed ammonia-borane hydrolysis for efficient H2 release

Development of hierarchical architecture composed of heteroatom-doped porous carbon and earth-abundant transition metal for anchoring of noble metal nanoparticles (NPs) is essential but challengeable to improve catalytic performance for hydrogen production from ammonia-borane (AB) hydrolysis. In this study, we report the utilization of hierarchical porous nitrogen-doped carbon nanosheets encapsulated Co (Co-NC) synthesized by sodium chloride-template method for anchoring of Ru NPs toward hydrogen production from AB hydrolysis. The achieved Ru@Co-NC with an optimal Ru loading of 1.0 wt% delivers the highest catalytic activities with turnover frequencies of 568/1131 min−1 under aqueous/alkaline conditions at 25 ℃. The high performance for AB hydrolysis can be ascribed to the abundance of surface sites, fast mass/electron transfer and the electronic metal-support interaction between ultrafine Ru NPs and Co-NC, which facilitate the oxidative cleavage of the OH bonds in attacked H2O molecules (rate-determining step). Besides, this catalyst can be easily isolated by an external magnet and exhibits relatively good reusability with high maintained activity after five cycles. This work emphasizes the utilization of magnetically hierarchical architecture as support for noble metal NPs toward catalytic hydrogen generation.

Polar O–Co–P Surface for Bimolecular Activation in Catalytic Hydrogen Generation

Boron hydrides release an abundant amount of hydrogen in the presence of a suitable catalyst. Accelerating bimolecular activation kinetics is the key to designing cost‐effective catalysts for borohydride hydrolysis. In this study, the bimolecular activation of a polar O–Co–P site demonstrated superior hydrogen‐generation kinetics (turnover frequency, TOF = 37 min−1, 298 K) and low activation energy (41.0 kJ mol−1) close to that of noble‐metal‐based catalysts. Through a combination of experiments and theoretical calculations, it was revealed that the activated dangling oxygen atom in the Co–O precursor effectively replaced via surface‐phosphorization because of strong electronic interactions between the dangling oxygen and P atoms. This substitution modulated the local coordination environment and electronegativity around the surface Co sites and formed a new polar O–Co–P active site for optimizing the activation kinetics of ammonia borane and water. This strategy based on bimolecular activation may create new avenues in the field of catalysis.