Commercializable power source from forming new states of hydrogen

The data from a broad spectrum of investigational techniques strongly and consistently indicates that hydrogen can exist in lower-energy states than previously thought possible. The predicted reaction involves a resonant, nonradiative energy transfer from otherwise stable atomic hydrogen to a catalyst capable of accepting the energy. The product is H(1/p  ), fractional Rydberg states of atomic hydrogen called “hydrino atoms” wherein n=(1/2,1/3,1/4,…1/p)$n=(1/2,1/3,1/4,\dots 1/p)$ (p ≤ 137 is an integer) replaces the well-known parameter n = integer in the Rydberg equation for hydrogen excited states. Atomic lithium and molecular NaH served as catalysts since they meet the catalyst criterion—a chemical or physical process with an enthalpy change equal to an integer multiple m of the potential energy of atomic hydrogen, 27.2 eV (e.g. m = 3 for Li and m = 2 for NaH). Specific predictions based on closed-form equations for energy levels of the corresponding hydrino hydride ions H⁻(1/4) of novel alkali halido hydrino hydride compounds (MH*X; M = Li or Na, X = halide) and molecular hydrino H₂(1/4) were tested using chemically generated catalysis reactants.     

Electron paramagnetic resonance proof for the existence of molecular hydrino

Quantum mechanics postulates that the hydrogen atom has a stable ground state from which it can be promoted to excited states by capture of electromagnetic radiation, with the energy of all possible states given by E_n = ?13.598/n² eV, in which n ≥ 1 is a positive integer. It has been previously proposed that the n = 1 state is not the true ground state, and that so-called hydrino states of lower energy can exist, which are characterized by fractional quantum numbers n = 1/p, in which 1 < p ≤ 137 is a limited integer. Electron transition to a hydrino state, H(1/p) is non-radiative and requires a quantized amount of energy, 2mE₁ (m is an integer), to be transferred to a catalyst. Numerous putative hydrino-forming reactions have been previously explored and the products have been characterized by a range of analytical methods. Molecular hydrino has been predicted to be paramagnetic. Here, we give an account of an electron paramagnetic resonance (EPR) study of molecular hydrino H₂(1/4) that was produced as gaseous inclusion in polymeric Ga(O)OH by a plasma reaction of atomic hydrogen with non-hydrogen bonded water as the catalyst. A sharp, complex, multi-line EPR spectrum is found, whose detailed properties prove to be consistent with predictions from hydrino theory. Molecular hydrino was also identified in gas chromatography as a compound faster than molecular hydrogen.     

Solid fuels that form HOH catalyst

Atomic hydrogen is predicted to form fractional Rydberg energy states H(1/p) called “hydrino atoms” wherein n = 1/2,1/3,1/4,…,1/p (p ≤ 137 is an integer) replaces the well-known parameter n = integer in the Rydberg equation for hydrogen excited states. The transition of H to a stable hydrino state H[a_H/p = m + 1] having a binding energy of p²⋅13.6 eV occurs by a nonradiative resonance energy transfer of m⋅27.2 eV (m is an integer) to a matched energy acceptor such as nascent H₂O that has a potential energy of 81.6 eV (m = 3). The nascent H₂O molecule formed by an oxidation reaction of OH⁻ at a hydrogen anode is predicted to serve as a catalyst to form H(1/4) with an energy release of 204 eV compared to the 1.48 eV required to produce H from electrolysis of H₂O. CIHT cells, each comprising a LiOH–LiBr eutectic mixture as the electrolyte exploit hydrino formation as a half-cell reaction to serve as a new electrical energy source. Net electrical production over the electrolysis input and hydrogen supplied to the anode was measured using an Arbin BT 2000. The electrical energies were continuously output over long-duration, measured on different systems, configurations, and modes of operation and were typically multiples of the electrical input that in most cases exceed the input by a factor of about 2 at about 10 mW/cm² anode area. The power density was increased by a factor of over 10 by running a corresponding high current. The thermal energy balance of solid fuels that form the HOH catalyst by a reaction akin to those of CIHT cells were measured using both a water flow calorimeter and a Setaram DSC 131 differential scanning calorimeter (DSC). The DSC results confirmed water flow calorimetric (WFC) results and the former were further independently replicated at Setaram Instrumentation based in France. The thermal energy balance for solid fuels such as Co(OH)₂ + CuBr₂ and Cu(OH)₂ + CuBr₂ were up to 60 times the maximum theoretical for both types of calorimeters with supportive XRD of the WFC products. DSC performed on FeOOH and Cu(OH)₂ + FeBr₂ in gold crucibles at Perkin Elmer showed up to four times the maximum theoretical energy. DSC and XRD were independently performed on the starting materials. The MAS ¹H NMR showed a predicted upfield matrix shift of a KOH–KCl hydrino getter when exposed to the gas from a reacting Cu(OH)₂ + CuBr₂ solid fuel in a sealed cell. A Raman peak starting at 1950 cm⁻¹ matched the free space rotational energy of H₂(1/4) (0.2414 eV). The solid fuels scaled linearly to over 5 kW and confirm the energetic reaction of hydrinos and may serve as a thermally reversible system to continuously generate power for commercial uses.     

Commercializable power source using heterogeneous hydrino catalysts

Using Maxwell's equations, the structure of the electron was derived by Mills as a boundary-value problem wherein the electron comprises the source current of time-varying electromagnetic fields during transitions with the constraint that the bound n = 1 state electron cannot radiate energy. A reaction predicted by the solution involves a resonant, nonradiative energy transfer from otherwise stable atomic hydrogen to a catalyst capable of accepting the energy. Specifically, a catalyst comprises a chemical or physical process with an enthalpy change equal to an integer multiple m of the potential energy of atomic hydrogen, 27.2 eV. The product is H (1/p  ), fractional Rydberg states of atomic hydrogen called “hydrino atoms” wherein  n=1/2,1/3,1/4,…,1/p$n=1/2,1/3,1/4,\dots ,1/p$ (p ≤ 137 is an integer) replaces the well-known parameter n = integer in the Rydberg equation for hydrogen excited states. The reaction step of a nonradiative energy transfer of an integer multiple of 27.2 eV from atomic hydrogen to the catalyst results in an ionized catalyst and free electrons that may cause the reaction to rapidly cease due to charge accumulation. Li, K, and NaH served as the catalysts to form hydrinos at a rapid rate when a high-surface-area conductive support doped with an oxidant was added to speed up the rate limiting step, the removal of electrons from the catalyst as it is ionized by accepting the nonradiative resonant energy transfer from atomic hydrogen to form hydrinos. The concerted electron-acceptor reaction from the catalyst to oxidant via the support was also exothermic to heat the reactants and enhance the rates. Using water-flow, batch calorimetry, the measured power and energy gain from these heterogeneous catalyst systems were up to over 10 W/cm³ (reactant volume) and a factor of over six times the maximum theoretical, respectively. The reaction scaled linearly to 580 kJ that developed a power of about 30 kW. Solution ¹H NMR on samples extracted from the reaction products in DMF-d7 showed the predicted H₂ (1/4) and H⁻ (1/4) at 1.2 ppm and −3.8 ppm, respectively. ToF-SIMs showed sodium hydrino hydride peaks such as NaH_x, peaks with NaH catalyst, and the predicted 11 eV binding energy of H⁻ (1/4) was observed by XPS. In an advancement over prior NaOH-doped Raney Ni power systems, the reactants of each solid fuel or heterogeneous-catalyst system can be regenerated from the products using commercial chemical-plant systems. Based on the observed energy gain and successful thermal regeneration, green power plants can be operated continuously as power and eutectic-melt electrolysis or thermal regeneration reactions are maintained in synchrony. The system is closed except that only hydrogen consumed in forming hydrinos need be replaced. Hydrogen can be obtained ultimately from the water with 200 times the energy release relative to combustion. These results indicate current commercial feasibility.     

Catalyst Induced Hydrino Transition (CIHT) electrochemical cell

Atomic hydrogen is predicted to form fractional Rydberg energy states H(1/p) called ‘hydrino atoms’ wherein n = 1/2,1/3,1/4,…,1/p (p ≤ 137 is an integer) replaces the well‐known parameter n = integer in the Rydberg equation for hydrogen excited states. The transition of H to a stable hydrino state H[a_H/p = m + 1] having a binding energy of p² × 13.6 eV occurs by a nonradiative resonance energy transfer of m × 27.2 eV (m is an integer) to a matched energy acceptor such as nascent H₂O which has a potential energy of 81.6 eV (m = 3) to form an intermediate that decays with the emission of continuum bands with short wavelength cutoffs and energies of m² × 13.6 eV. The predicted H(1/4) continuum radiation in the region 10 to 30 nm was observed first at BlackLight Power, Inc. (BLP) and reproduced at the Harvard Center for Astrophysics (CfA) wherein H₂O catalyst was formed by a hydrogen reduction reaction at the anode of a hydrogen pinch plasma. By the same mechanism, the nascent H₂O molecule formed by an oxidation reaction of OH^? at a hydrogen anode is predicted to serve as a catalyst to form H(1/4) with an energy release of 204 eV compared to the 1.48 eV required to produce H from electrolysis of H₂O. CIHT cells, each comprising a Ni anode, NiO cathode, a LiOH–LiBr eutectic mixture as the electrolyte, and MgO matrix exploit hydrino formation as a half‐cell reaction to serve as a new electrical energy source. The cells were operated under intermittent H₂O electrolysis to generate H at the anode and then discharged to form hydrinos wherein trace H₂O vapor was supplied as entrained in an inert gas flow in otherwise closed cells. Net electrical production over the electrolysis input was measured using an Arbin BT 2000 (<0.1% error) and confirmed using a digital oscilloscope, wherein no theoretical conventional energy was possible. Materials characterizations included those that quantified any compositional change of the electrolyte by elemental analysis using ICPMS, XRF, and XRD, and SEM were performed on the anode. The electrical energies were continuously output over long‐duration, measured on different systems, configurations, and modes of operation and were typically multiples of the electrical input that in most cases exceed the input by a factor of greater than 10. Calorimetry of solid fuels that exploited the same catalyst and a similar reaction mechanism showed excess thermal energy greater than 10 times the maximum possible from any conventional reaction. The predicted molecular hydrino H₂(1/4) was identified as a product of CIHT cells and solid fuels by MAS ¹H NMR, ToF‐SIMS, ESI‐ToFMS, electron‐beam excitation emission spectroscopy, Raman spectroscopy, photoluminescence emission spectroscopy, FTIR, and XPS. Copyright © 2013 John Wiley & Sons, Ltd.     

Bonding states of hydrogen for supported Ti clusters on pristine and defective graphene

To determine whether graphene-supported Ti clusters can synergistically store hydrogen through Kubas and spillover effect, we systematically investigate the growth pattern of Ti_n (n = 1–10) clusters on pristine and defective graphene and analyze multiple types of bonding states of hydrogen in detail. For pristine graphene, the most stable Ti_n (n = 1–10) clusters are the quasi-planar structure except for supported Ti₄ and Ti₅. The Ti dissociation energies and the binding energy of Ti_n clusters gradually increase with increasing n, which indicates that larger Ti_n clusters tend to form. Efficient spillover will occur on single-site Ti Catalysts at low hydrogen concentration due to the lower hydrogen spillover energy barrier (3.05 eV), while the energy barrier of hydrogen migration from Tin (n = 2–7) clusters to graphene on the cluster is 5.34–6.82 eV. The Ti: H ratio is a maximum of 1:8 for the single-site Ti catalyst, while decreases with the Tin cluster increases. Therefore, the pristine graphene-supported Ti nanoclusters are more suitable as substrates for hydrogen adsorbent rather than spillover. The introduced defects make Ti_n clusters have three-dimensional conical configurations from n = 4. Ti₃ and Ti₆ are the most stable clusters. Moreover, the migration energy barriers of H atoms on them decrease from 6.54 eV to 6.82 eV–4.32 eV and 3.42 eV, respectively. Our results explain recent experimental phenomena [Appl Phys Lett 2015; 106: 083,901. ACS Energy Lett 2022; 7 (7): 2297–2303] in depth at the molecular level.     

Substitutional V–Pd alloys for the membranes permeable to hydrogen: Hydrogen solubility at 150–400 °C

The development of non-palladium membrane for separation of hydrogen from gas mixtures is one of critical challenges of hydrogen energy. Vanadium based materials are most promising for such membranes. The alloying of pure vanadium is crucially important for reduction of hydrogen solubility to an optimal value. Solution of hydrogen in substitutional V-xPd alloys (x = 5, 7.3, 9.7, 12.3, 18.8 at%) was investigated. The pressure–composition-isotherms were obtained in the range of pressure (10–10⁶) Pa, temperature (150–400) °С and concentration of hydrogen, H/M, from 4·10⁻⁴ to 0.6. The alloying of vanadium with palladium was found to reduce the hydrogen solubility substantially greater than the alloying with other elements, e.g. by Ni and Cr. The hydrogen absorption in the V–Pd alloys obeyed Siverts' law including the range of undiluted solution with hydrogen concentration H/M > 0.1. The reduction in the hydrogen solubility due to the alloying of V with Pd was caused mainly by increase in the enthalpy of solution at nearly constant entropy factor. Changes in the gross electronic structure of metal are most probably responsible for the effects of alloying on the hydrogen solubility in the substitutional V–Pd alloys.     

Theoretical study on the structural evolution and hydrogen storage in NbHn (n = 2–15) clusters

Niobium hydrides are attractive superconductors. Exploring the formation process of niobium hydrides is essential to elucidate the mechanism of superconductivity. One of the key issues is to clarify the atomic stacking patterns of Nb and H atoms, i.e., the structural evolution of Nb–H clusters. Here, the low-energy structural isomers of NbH_n (n = 2–15) clusters are determined using the CALYPSO method combined with density functional theory calculations. Geometries were fully optimized at the B3LYP/LANL2DZ/6–311++G(d) level of theory to determine global minimum structures for each size. The results indicate that NbH₁₃ is the most stable cluster in this size range. The 4d atomic orbital of Nb and the hydrogen 1s atomic orbital participate largely to the internal binding of the NbH₁₃ cluster. They hydrogen storage density and adsorption energy of this cluster are calculated to be 12.4 wt% and 2.58 eV, respectively. The high hydrogen storage density, suitable hydrogen adsorption energy, and high stability of NbH₁₃ shows promise as a hydrogen storage material. These results provide fundamental information for further design of metal hydrogen storage materials.     

High-capacity hydrogen storage in Li-decorated (AlN)n (n = 12, 24, 36) nanocages

The capability of Li-decorated (AlN)_n (n = 12, 24, 36) nanocages for hydrogen storage has been studied by using density functional theory (DFT) with the generalized gradient approximation (GGA). It is found that each Al atom is capable of binding one H₂ molecule up to a gravimetric density of hydrogen storage of 4.7 wt% with an average binding energy of 0.189, 0.154, and 0.144 eV/H₂ in the pristine (AlN)_n (n = 12, 24, 36) nanocages, respectively. Further, we find that Li atoms can be preferentially decorated on the top of N atoms in (AlN)_n (n = 12, 24, 36) nanocages without clustering, and up to two H₂ molecules can bind to each Li atom with an average binding energy of 0.145, 0.154, 0.102 eV/H₂ in the Li_n(AlN)_n (n = 12, 24, 36) nanocages, respectively. Both the polarization of the H₂ molecules and the hybridization of the Li-2p orbitals with the H-s orbitals contribute to the H₂ adsorption on the Li atoms. Thus, the Li-decorated (AlN)_n (n = 12, 24, 36) nanocages can store hydrogen up to 7.7 wt%, approaching the U.S. Department of Energy (DOE) target of 9 wt% by the year 2015, and the average binding energies of H₂ molecules lying in the range of 0.1–0.2 eV/H₂ are favorable for the reversible hydrogen adsorption/desorption at ambient conditions. It is also pointed out that when allowed to interact with each other, the agglomeration of Li-decorated (AlN)_n nanocages would lower the hydrogen storage capacity.     

Two-dimensional B7P2: Dual-purpose functional material for hydrogen evolution reaction/hydrogen storage

It is well known that the development of dual-purpose materials is more significant and valuable than single-use materials due to the diversity of their use purposes. Based on density functional theory (DFT), the hydrogen evolution/hydrogen storage characteristics of two-dimensional (2D) B₇P₂ monolayer are systematically studied in this paper, focusing on the key word of clean energy-“hydrogen”. The results show that the B₇P₂ monolayer can be used as a stable metal-free decorated catalyst for hydrogen evolution reaction (HER), which is renewable and environmentally friendly. The calculated Gibbs free energy (ΔG_H1) is 0.06 eV, which is comparable or even better than that of Pt catalyst (ΔG_H1 = ?0.09 eV). In addition, we also found that the increase of hydrogen coverage and strain driving (?2%–2%) did not further enhance the HER activity of B₇P₂ monolayer, showing a poor ΔG_H1. In the aspect of hydrogen storage, we have investigated the hydrogen storage performances of alkali-metal (Li, Na and K) doped B₇P₂. It is found that in the fully loaded case, B₇P₂Li₆ is a promising hydrogen storage material with a 7.5 wt% H₂ content and 0.15 eV/H₂ average hydrogen adsorption energy (E_ave). Moreover, ab initio molecular dynamics (AIMD) calculations show that there is no dynamic barrier for H₂ desorption of Li-decorated B₇P₂ monolayer. In conclusion, our results indicate that the B₇P₂ monolayer is not only an excellent catalyst for HER, but also a promising hydrogen storage medium.     

Lattice contraction of cerium hydrides from first-principles LDA + U calculations

Ce can be loaded with H forming complicated continuous solid solution and compounds, and causing remarkable electronic-structure changes. First-principles pseudopotential plane wave method with adding a Hubbard parameter U for considering the strong Coulomb correlation between localized 4f electron is employed to investigate the electronic and structural properties of stoichiometric and nonstoichiometric face-centered cubic (fcc) Ce hydrides (CeH_x, x = 2, 2.25, 2.5, 2.75 and 3, respectively.). The most remarkable result is the decreasing trend of the calculated lattice parameters with increasing H composition, which is resulted from the associated effects of the enhanced chemical bonding owing to the participation of Ce 5d electron and, the size effects owing to the small H atomic radius and the large volume of octahedral interstice thus in favor of reducing the atomic distance for the formation of chemical bonding between Ce and octahedral H atoms.     

Metal-nonmetal atom co-doping engineered transition metal disulfide for highly efficient hydrogen evolution reaction

The development of effective and non-precious electrocatalyts for hydrogen evolution reaction (HER) has attracted massive research interests. Herein, we report a density functional theory (DFT) investigation on the activation and optimization of Molybdenum disulfide (MoS₂) monolayer as efficient HER electrocatalysts by cobalt-nonmetal atom (X = B, C, N, P, Se) codoping. Our results show that three CoX-MoS₂ (X = C, N, and Se) catalysts display enhanced HER performance with |ΔG_H|s in the range of 0.12–0.23 eV. Careful electronic structure analysis manifests that the favorable H adsorption process on the MoS₂ basal plane is induced by suitable in-gap states upon codoping. Furthermore, appropriate biaxial strain can help optimize the HER performance of these co-doped systems, e.g, the ΔG_Hs of CoC@MoS₂, CoN@MoS₂, and CoSe@MoS₂ reaches 0.0 eV, ?0.04 eV, and ?0.01 eV at 1.86% tensile strain, 5% compressive strain, and 4% compressive strain, respectively. Our work offers a highly promising catalyst for HER and guides the atomic design of more efficient non-noble electrocatalysts.     

Hydrogen production via catalytic steam reforming of the aqueous fraction of bio-oil using nickel-based coprecipitated catalysts

Hydrogen production was studied in the catalytic steam reforming of a synthetic and a real aqueous fraction of bio-oil. Ni/Al coprecipitated catalysts with varying nickel content (23, 28 and 33 relative atomic %) were prepared by an increasing pH technique and tested during 2 h under different experimental conditions in a small bench scale fixed bed setup. The 28% Ni catalyst yielded a more stable performance over time (steam-to-carbon molar ratio, S/C = 5.58) at 650 °C and a catalyst weight/organic flow rate (W/m_org) ratio of 1.7 g catalyst min/g organic. Using the synthetic aqueous fraction as feed, almost complete overall carbon conversion to gas and hydrogen yields close to equilibrium could be obtained with the 28% Ni catalyst throughout. Up to 63% of overall carbon conversion to gas and an overall hydrogen yield of 0.09 g/g organic could be achieved when using the real aqueous fraction of bio-oil, but the catalyst performance showed a decay with time after 20 min of reaction due to severe coke deposition. Increasing the W/m_org ratio up to 5 g catalyst min/g organic yielded a more stable catalyst performance throughout, but overall carbon conversion to gas did not surpass 83% and the overall hydrogen yield was only ca. 77% of the thermodynamic equilibrium. Increasing reaction temperatures (600–800 °C) up to 750 °C enhanced the overall carbon conversion to gas and the overall yield to hydrogen. However, at 800 °C the catalyst performance was slightly worse, as a result of an increase in thermal cracking reactions leading to an increased formation of carbon deposits.     

Revealing the interfacial phenomenon of metal-hydride formation and spillover effect on C48H16 sheet by platinum metal catalyst (Pt (n=1-4)) for hydrogen storage enhancement

Hydrogen is a worldwide green energy carrier, however due its low storage capacity, it has yet to be widely used as an energy carrier. Therefore, the quantum chemical method is being employed in this investigation for better understand the hydrogen storage behaviour on Pt _(n = 1-4) cluster decorated C₄₈H₁₆ sheet. The Pt_(n = 1-4) clusters are strongly bonded on the surface of C₄₈H₁₆ sheet with binding energies of ?3.06, ?4.56, ?3.37, and ?4.03 eV respectively, while the charge transfer from Pt_(n = 1-4) to C₄₈H₁₆ leaves an empty orbital in Pt atom, which will be crucial for H₂ adsorption. Initially, the molecular hydrogen is adsorbed on Pt_(n = 1-4) decorated C₄₈H₁₆ sheet through the Kubas interaction with adsorption energies of ?0.85, ?0.66, ?0.72, and ?0.57 eV respectively, while H–H bond is elongated due to the transfer of electron from σ (HH) orbital to unfilled d orbital of the Pt atom, resulting in a Kubas metal-dihydrogen complexes. Furthermore, the dissociative hydrogen atoms adsorbed on Pt_(n = 1-4) decorated C₄₈H₁₆ sheet have adsorption energies of ?1.14 eV, ?1.02 eV, ?0.95 eV, and ?1.08 eV, which are greater than the molecular hydrogen adsorption on Pt_(n = 1-4) cluster supported C₄₈H₁₆ sheet with lower activation energy of 0.007, 0.109, 0.046, and 0.081 eV respectively. To enhance the dissociative hydrogen adsorption energy, positive and negative external electric fields are applied in the charge transfer direction. Increasing the positive electric field makes H–H bond elongation and good adsorption, whereas increasing the negative electric field results H–H bond contraction and poor adsorption. Thus, by applying a sufficient electric field, the H₂ adsorption and desorption processes are can be easily tailored.     

Numerical study on fast filling of 70 MPa type III cylinder for hydrogen vehicle

There will be significant temperature rise within hydrogen vehicle cylinder during the fast filling process. The temperature rise should be controlled under the temperature limit (85 °C) of the structure material (set by ISO/TS 15869), because it may lead to the failure of the structure. In this paper, a 2-dimensional axisymmetric computational fluid dynamics (CFD) model for fast filling of 70 MPa hydrogen vehicle cylinder is presented. The numerical simulations are based on the modified standard k − ? turbulence model. In addition, both the equation of state for hydrogen gas and the thermodynamic properties are calculated by National Institute of Standards and Technology (NIST) database: REFPROP 7.0. The thermodynamic responses of fast filling with different pressure-rise patterns and filling times within type III cylinder have been analyzed in detail.     

Crystal structure of GdNi3 with superlattice alloy and its hydrogen absorption–desorption property

We synthesized the intermetallic compound GdNi₃, which has a PuNi₃-type structure (space group R-3m), and investigated its P–C isotherm. The refined lattice parameters were a = 0.4993(1) nm and c = 2.4536(4) nm. In the first absorption process, two plateaus were observed, and the maximum hydrogen capacity reached 1.07 H/M. In the first desorption process, a narrow and sloping plateau was observed at approximately 0.02 MPa. After the first full desorption, 0.6 H/M of hydrogen remained in the sample. This sample showed severe peak broadening in the XRD pattern, indicating that the metal sublattice deformed from the original alloy. No plateau region was observed in the second absorption–desorption cycle.     

High-loaded sub-6 nm Cu catalyst with superior hydrothermal-stability and efficiency for aqueous phase reforming of methanol to hydrogen

Developing an efficient, hydrothermally stable and non-noble metal catalyst is a key for application of aqueous-phase reforming of methanol (APRM) to produce hydrogen in situ. Herein, a Cu@NC catalyst with high metal loading (44.9 wt %) and sub-6 nm Cu nanoparticle size was synthesized by pyrolyzing Cu-chitosan chelates. The coordination between metal ions (Cu²⁺) and amine functional groups in chitosan enabled high metallic dispersion in Cu-chitosan chelates. After pyrolysis, the Cu nanoparticles were embedded in N-doped carbon (NC) matrix. This confinement effect ensured remarkable hydrothermal stability for the Cu@NC catalyst. As a result, a high hydrogen production rate of 34.0 μmol·g_cat^?1·s^?1 was obtained over Cu@NC-200 catalyst, about 12.6 times higher than that of a traditionally impregnated Cu/C catalyst. Notably, no deactivation and aggregation of Cu nanoparticle were observed after 200 h’ running in APRM, indicating excellent hydrothermal stability of the Cu@NC catalyst. Thus, this work developed a simple strategy to prepare an efficient and robust catalyst that could work well under hash hydrothermal conditions for application of APRM on the compact mobile devices.     

Biological fermentative hydrogen and ethanol production using continuous stirred tank reactor

Hydrogen and ethanol are promising biofuels and have great potential to become alternatives to fossil fuels. The influence of organic loading rates (OLRs) on the production of fermentative hydrogen and ethanol were investigated in a continuous stirred tank reactor (CSTR) from fermentation using molasses as substrate. Four OLRs were examined, ranging from 8 to 32 kg/m³·d. The H₂ and ethanol production rate in CSTR initially increased with increasing OLR (from 8 to 24 kg/m³ d). The highest H₂ production rate (12.4 mmol/h l) and ethanol production rate (20.27 mmol/h l) were obtained in CSTR both operated at OLR = 24 kg/m³ d. However, the H₂ and ethanol production rate tended to decrease with an increase of OLR to 32 kg/m³ d. The liquid fermentation products were dominated by ethanol, accounting for 31-59% of total soluble metabolities. Linear regression results show that ethanol production rate (y) and H₂ production rate (x) were proportionately correlated which can be expressed as y = 0.5431x + 1.6816 (r² = 0.7617). The total energy conversion rate based on the heat values of H₂ and ethanol was calculated to assess the overall efficiency of energy conversion rate. The best energy conversion rate was 31.23 kJ/h l, occurred at OLR = 24 kg/m³ d.     

Well-defined core/shell pDA@Ni-MOF heterostructures with photostable polydopamine as electron-transfer-template for efficient photoelectrochemical H2 evolution

Here, novel core/shell polydopamine@Ni-MOF (pDA@Ni-MOF) heterogeneous nanostructures are synthesized via a simple one-pot nucleation-growth technique. This rational core/shell design method provide a uniform Ni-MOF shell thickness (shell: ～ 10 nm) as well as homogeneous wrapping of pDA templates with quite narrow size distributions. The obtained band properties of bare pDA (E_CB = ?0.35 eV and E_VB = 2.95 eV vs normal hydrogen electrode (NHE)) and bare Ni-MOF (E_CB = ?0.49 eV and E_VB = 2.85 eV vs NHE) clearly revealed charge separation is occurred on pDA by absorbing light due to π-π1 transition, and photogenerated electrons on conduction band (CB) of pDA was migrated to CB of Ni-MOF. Specifically, the photoelectrochemical (PEC) water performance of pDA@Ni-MOF photoanodes with highest current density is recorded as 8.61 mA/cm² at 0.77 V vs. RHE under visible LED irradiation, which is significantly higher than bare pDA (0.008 V vs. RHE) and bare Ni-MOF (0.011 V vs. RHE) at the same conditions. Note that, the higher photon absorption properties of pDA in core together with high interaction valence bond between two semiconductors could generate electron rich state giving rise to faster electron transfer kinetics as next generation of MOF based hybrid materials with regular morphologies.