Solar H2 Production From a Two-Step Water Splitting Process With Metal (Fe, Ni) Doped Ceria

2008 ◽  
Author(s):  
H. Kaneko ◽  
Y. Naganuma ◽  
S. Taku ◽  
K. Ouchi ◽  
N. Hasegawa ◽  
...  
Keyword(s):  
Solid Solution ◽  
Water Splitting ◽  
Metal Ion ◽  
Oxygen Deficiency ◽  
H2 Production ◽  
Doped Ceria ◽  
Solar Simulator ◽  
H2 Generation ◽  
Metal Doped ◽  
Splitting Process

Solar H2 production by the two-step water splitting process with thermochemical reaction has been proposed to convert solar energy into chemical energy. We succeeded in repeating the cyclic two-step water splitting process composed of the O2-releasing and H2-generation reactions with metal (Fe, Ni) doped ceria. The metal doped ceria with low content of metal ion (Fe3+, Ni2+) formed a solid solution with fluorite-type structure between ceria (CeO2) and metal oxide (Fe2O3, NiO). The empirical formula of the solid solution was Ce1-αMαO2−δ (M = Fe, Ni), and it was assumed that the high reactivity on the two-step water splitting process was due to an oxygen deficiency in the solid solution. The metal doped ceria with different Ce:M mole ratio (Ce:M = 0.97:0.03–0.7:0.3) was prepared through the combustion method. The two-step water-splitting process with metal doped ceria proceeded at 1673K for the O2-releasing reaction and at 1273K for the H2-generation reaction by irradiation of an infrared imaging lamp for a solar simulator. The amounts of H2 gas evolved in the H2-generation reaction with Fe-doped ceria and Ni-doped ceria with different Ce:M (M = Fe, Ni) mole ratio were 0.97–1.8 and 1.7–2.5 cm3/g, respectively, and the evolved H2/O2 ratios were approximately equaled to 2 of the stoichiometric value. The amounts of H2 and O2 gases evolved in the two-step water splitting process varied with the Ce:M mole ratio in the metal doped ceria. It was suggested that the O2-releasing and H2-generation reactions with metal doped ceria was repeated with the reduction and oxidation of Ce4+-Ce3+ enhanced by the presence of Fe or Ni ions. Furthermore, the O2-releasing reaction with Ni-doped ceria proceeded under a high O2 partial pressure atmosphere (pO2 = 0.05 atm) and at the temperature of 1773K. The progress of the O2-releasing reaction under a high pO2 indicates that metal doped ceria can be applicable for the rotary-type solar reactor developed by Tokyo Tech group for solar H2 production.

Simultaneous Production of H2 and O2 With Rotary-Type Solar Reactor (Tokyo Tech Model) for Solar Hybrid Fuel

2008 ◽  
Author(s):  
Y. Tamaura ◽  
H. Kaneko ◽  
Y. Naganuma ◽  
S. Taku ◽  
K. Ouchi ◽  
...  
Keyword(s):  
Solid Solution ◽  
Water Splitting ◽  
Rotation Rate ◽  
Slow Rotation ◽  
Gas Evolution ◽  
Simultaneous Production ◽  
H2 Generation ◽  
Solar Reactor ◽  
Splitting Process ◽  
Rotary Type

The rotary-type solar reactor has been developed for solar hydrogen production with the two-step water splitting process using the reactive ceramic (Ni, Mn-ferrite). The rotary-type reactor has the rotating tubular cylinder covered on a reactive ceramic and dual reaction cells for O2-releasing and H2-generation reactions. The successive evolutions of O2 and H2 gases were observed in the O2 releasing and H2 generation reaction cells, respectively, with the prototype (small) reactor (diameter of cylinder ; 4cm). There is an upper limit for the rate of H2 gas evolution in the case of the prototype reactor because of the slow rotation rate in a small irradiation area. To confirm the practical operation of the rotary-type solar reactor with the two-step water splitting process for the simultaneous production of H2 and O2 gases, a scaled-up rotary-type solar reactor with 400cm2 of the irradiation area was fabricated (diameter; 50cm). The scaled-up reactor made of inner and outer short tubular cylinders (stainless steel) has a quartz glass window for the irradiation of reactive ceramic coated on the inner tubular cylinder (cylindrical rotor) and reaction cells were aligned in the sharing spaces between the inner and outer short tubular cylinders with gas sealing mechanisms. In the reactor, reactive ceramic coated on the inner tubular cylinder was heated up to 1800K by using the infrared imaging lamps (solar simulator) with thermal flux = 600kW/m2. The solid solution between YSZ and Ni-ferrite was used as reactive ceramic for the scaled-up reactor in order to prevent from sintering at a high temperature in the O2-releasing reaction, since the sintering of reactive ceramic resulted in lowering the yield of H2 gas evolution in the H2-generation reaction. The amounts of H2 and O2 gases evolved at the rotation rate of 0.3rpm were evaluated to 64cm3 and 30cm3 for 10min with the scaled-up rotary-type solar reactor, respectively, which were much larger than those with the prototype reactor. The simultaneous evolutions of H2 and O2 gases in the two-step water splitting process were repeated by employing the scaled-up reactor with the solid solution between YSZ and Ni-ferrite.

Anchoring Zn0.5Cd0.5S solid solution onto 2D porous Co-CoO nanosheets for highly improved photocatalytic H2 generation

2021 ◽  
Author(s):  
Xueyou Gao ◽  
Deqian Zeng ◽  
Qingru Zeng ◽  
Zongzhuo Xie ◽  
Toyohisha Fujita ◽  
...  
Keyword(s):  
Solid Solution ◽  
Water Splitting ◽  
Noble Metal ◽  
H2 Production ◽  
Two Dimensional ◽  
Photocatalytic Water Splitting ◽  
H2 Generation ◽  
Photocatalytic H2 Generation

Co-based cocatalysts have attracted considerable attention as potential alternatives for the noble-metal (Pt) in photocatalytic water splitting. However, the two-dimensional (2D) porous-structured Co-based cocatalysts toward photocatalytic hydrogen (H2) production application...

Two-Step Water Splitting With Ni-Ferrite System for Solar H2 Production Using Concentrated Solar Radiation

Solar Energy ◽  
2004 ◽  
Author(s):  
Hirofumi Aoki ◽  
Hiroshi Kaneko ◽  
Noriko Hasegawa ◽  
Hideyuki Ishihara ◽  
Yoichiro Takahashi ◽  
...  
Keyword(s):  
Solid Solution ◽  
Water Splitting ◽  
Spinel Phase ◽  
H2 Production ◽  
Solution Phase ◽  
Reaction Yield ◽  
Solid Solution Phase ◽  
Solar Simulator ◽  
Concentrated Solar Radiation ◽  
Ferrite System

Two-step water splitting with Ni-ferrite (NiFe2O4) system for H2 production using concentrated solar thermal was examined. The O2 releasing reaction proceeded in air at 1800K by irradiation with Xe lamp beams which were used as a solar simulator. The stoichiometry and the reaction mechanism of the O2 releasing step were investigated by XRD. The reaction yield was estimated to be 48% from the calculation of the spinel phase lattice constant, and the XRD showed that the solid solution phase of (Ni, Fe)O between NiO and FeO was formed. The (Ni, Fe)O solid solution could lower the O2 releasing reaction temperature. In the H2 generating step for the sample obtained by the O2 releasing step, the reaction proceeded very fast and its yield was 90% of the theoretical one at 1123K. The XRD measurement indicated that the (Ni, Fe)O solid solution phase was changed to the spinel phase of Ni-ferrite in the H2 generation step.

Solar H2 Production With Tokyo Tech Rotary-Type Solar Reactor to be Tested Using Solar Concentration System at CSIRO in Australia

2009 ◽  
Author(s):  
Hiroshi Kaneko ◽  
Chong-il Lee ◽  
Yosuke Ishikawa ◽  
Koichiro Hosogoe ◽  
Yutaka Tamaura
Keyword(s):  
Solid Solution ◽  
Water Splitting ◽  
Reaction Temperature ◽  
Asia Pacific ◽  
Complex Method ◽  
Solar Simulator ◽  
H2 Generation ◽  
Solar Reactor ◽  
Test Operation ◽  
Rotary Type

The test operation of the Tokyo Tech rotary-type solar reactor (2nd model) is scheduled to be carried out using the solar concentrating system of CSIRO (New castle, Australia) as an international collaboration research between Japan (Tokyo Tech) and Australia (CSIRO) in APP (Asia-Pacific Partnership on Clean Development and Climate) project. The rotary-type solar reactor is positioned at an elevation of about 17 m. The input of solar power for the test operation is planned to be 50 kW from the solar concentrating system with about 10 heliostats. The estimation of evolved H2 gas was calculated from the amount of evolved O2 gas and the energy conversion efficiency is evaluated from the estimated amount of evolved H2 gas and the input of solar energy. The two-step water splitting process with the reactive ceramics of ceria-based solid solution (0.8CeO2−0.2ZrO2 prepared by the polymerized complex method) was investigated using the solar simulator of concentrated Xe lamp beams for the test operation of the rotary-type solar reactor at CSIRO solar concentrating system. The amounts of O2 and H2 gases evolved in the two-step water splitting reaction with CeO2-ZrO2 solid solution were determined for the H2-generation reaction temperatures of 773, 1273 and 1473 K. The amounts of evolved H2 gas decreased with an increase of the reaction temperature, however, the lowering of H2 gas evolution at 1473 K was 20% in comparison with that at 773 K. The heating time of the reactive ceramics up to the O2-releasing reaction temperature is evaluated to 3 s, when the difference between the O2-releasing reaction temperature (1773 K) and the H2-generation reaction temperature (1473 K) is 300 K.

Two-Step Water Splitting Process With Solid Solution of YSZ and Ni-Ferrite for Solar Hydrogen Production (ISEC 2005-76151)

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Hideyuki Ishihara ◽  
Hiroshi Kaneko ◽  
Noriko Hasegawa ◽  
Yutaka Tamaura
Keyword(s):  
Thermal Stability ◽  
Solid Solution ◽  
Hydrogen Production ◽  
Water Splitting ◽  
Solar Hydrogen ◽  
H2 Generation ◽  
Concentrated Solar Energy ◽  
Solar Hydrogen Production ◽  
Gas Volume ◽  
Splitting Process

Ni-ferrite (NiFe2O4) is a promising reactive ceramics of the ferrite for the solar hydrogen production by a two-step water splitting process using concentrated solar energy. However, it should be pretreated before H2-generation reaction by grinding the Ni-ferrite sintered after the O2-releasing reaction to make a fine powder. If the Ni-ferrite and yttria stabilized zirconia (YSZ) form a solid solution between these oxides (YSZ∕NiFe2O4 solid solution=YSZ(Ni,Fe)), it is expected that the two-step water splitting process with the Ni-ferrite system can proceed without treatment of the reduced product because of the high thermal stability of the YSZ∕NiFe2O4 solid solution. The YSZ∕NiFe2O4 solid solution was prepared by calcination of the mixture of the YSZ balls and NiFe2O4 powder at T=1823K for 1h, and its reactivity and thermal stability were examined for the two-step water splitting process. During the ten times repetition of the two-step water splitting reaction (T=1773K for O2-releasing, and 1473K for H2-generation) with the YSZ∕NiFe2O4 solid solution using infrared imaging furnace, the reactivity for O2-releasing and H2-generation was kept constant. The molar ratio of the released O2 gas volume (the average O2 gas, 1.9cm3∕g) and the generated H2 gas volume (the average H2 gas, 3.8cm3∕g) was nearly 1:2, indicating that the water decomposition process via two steps proceeds. The X-ray diffractometry (XRD) measurement showed that the YSZ(Ni,Fe) keeps the YSZ phase structure during the ten times repetition of the two-step water splitting process. The successive H2 gas production by the two-step water splitting process was performed (ten times repetition of the two-step water splitting process). From comparative study on the reactivity and the thermal stability for the two-step water splitting reaction among the YSZ∕NiFe2O4 solid solution, NiFe2O4 and ZnFe2O4, it is concluded that the YSZ∕NiFe2O4 solid solution is superior to the others.

scholarly journals Photoelectrochemical water splitting process using titanium dioxide photocatalyst: A brief overview

2021 ◽  
Vol 1 (1) ◽  
pp. 26-35
Author(s):  
Chin Wei Lai ◽  
Jenny Hui Foong Chau
Keyword(s):  
Titanium Dioxide ◽  
Water Splitting ◽  
Energy Supply ◽  
Fossil Fuel ◽  
Lower Cost ◽  
Photoelectrochemical Water Splitting ◽  
Tio2 Photocatalyst ◽  
H2 Generation ◽  
Sustainable Energy Supply ◽  
Splitting Process

Hydrogen (H2) has proved itself as a viable future energy carrier and alternative for fossil fuel in terms of ensuring a clean and sustainable energy supply. However, H2 must be made available at a lower cost so that everyone can benefit from it and prevent causing a worldwide ecological imbalance. The usage of photoelectrochemical water splitting (PEC) technology by using TiO2 photocatalyst can produce H2 using renewable solar energy. The essential milestones, as well as the mechanism in PEC H2 generation, are discussed in this article.

H2 Generation by Two-Step Water Splitting With CeO2-MOx Using Concentrated Solar Thermal Energy

Solar Energy ◽  
2006 ◽  
Author(s):  
Hiroshi Kaneko ◽  
Hideyuki Ishihara ◽  
Takao Miura ◽  
Hiromitsu Nakajima ◽  
Noriko Hasegawa ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Thermal Energy ◽  
Infrared Imaging ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Solar Simulator ◽  
Solar Hydrogen ◽  
H2 Generation ◽  
Solar Hydrogen Production

CeO2-MOx (M = Mn, Fe, Ni, Cu) reactive ceramics, having high melting points and high conductivities of O2−, were synthesized with the combustion method from their nitrates for solar hydrogen production. The prepared CeO2-MOx samples were solid solutions between CeO2 and MOx with the fluorite structure through XRD. Two-step water splitting reactions with CeO2-MOx reactive ceramics proceeded at 1573–1773K for the O2 releasing step and at 1273K for the H2 generation step by irradiation of infrared imaging furnace as a solar simulator. The amounts of O2 evolved in the O2 releasing reaction with CeO2-MOx and CeO2 systems increased with the increase of the reaction temperature. The amounts of H2 evolved in the H2 generation reaction with CeO2-MOx systems except for M = Cu were more than that of CeO2 system after the O2 releasing reaction at the temperatures of 1673 and 1773K. The largest amount of H2 was generated with CeO2-NiO after the O2 releasing reaction at 1573, 1673 and 1773K. The O2 releasing reaction at 1673K and H2 generation reaction at 1273K with CeO2-Fe2O3 were repeated four times with the evolving of O2 (1.3cm3/g-sample) and H2 (2.3cm3/g-sample) gases, respectively. The possibility of solar hydrogen production with CeO2-MOx (M = Mn, Fe, Ni) reactive ceramics system by using concentrated solar thermal energy was suggested.

Solar Hydrogen Productivity of Ceria–Scandia Solid Solution Using Two-Step Water-Splitting Cycle

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Chong-il Lee ◽  
Qing-Long Meng ◽  
Hiroshi Kaneko ◽  
Yutaka Tamaura
Keyword(s):  
Solid Solution ◽  
Water Splitting ◽  
High Performance ◽  
Oxygen Vacancies ◽  
Reaction Rate ◽  
Lattice Distortion ◽  
Complex Method ◽  
Solar Hydrogen ◽  
H2 Generation ◽  
Solar Hydrogen Production

The reactivity of CeO2–Sc2O3 solid solution for solar hydrogen production via two-step water-splitting reaction has been studied in this work. The CeO2–Sc2O3 solid solution was synthesized by polymerized complex method (PCM) with various Sc content between 0 and 20 mol. %. Analysis results from online direct gas mass spectrometry (DGMS) suggest that Ce3 + formed by CeO2–Sc2O3 solid solution in the O2-releasing step could be completely oxidized by H2O to generate hydrogen and return to Ce4 + in the H2-generation step. A Ce0.97Sc0.03O1.985 generates the largest amount of O2 and H2 among present samples, and the reduction and oxidation ratios are about 9.9% (Ce) and 10% (Ce), respectively. An estimated H2-generation reaction rate is about 4 ml g−1min−1 for Ce0.97Sc0.03O1.985. This value is about seven times greater than that of Ce0.89Zr0.11O2. The high reaction rate of Ce0.97Sc0.03O1.985 makes all formed Ce3 + completely oxidized by H2O in 5 min in the H2-generation step. The reasons for high performance are discussed from the views of lattice distortion and the amount of oxygen vacancies formed in the lattice.

Porous direct Z-scheme heterostructures of S-deficient CoS/CdS hexagonal nanoplates for robust photocatalytic H2 generation

CrystEngComm ◽  
2021 ◽  
Author(s):  
Zhihui Li ◽  
Hanchu Chen ◽  
Yanyan Li ◽  
Hui Wang ◽  
Yanru Liu ◽  
...  
Keyword(s):  
Water Splitting ◽  
H2 Production ◽  
Solar Fuels ◽  
Photocatalytic Water Splitting ◽  
H2 Generation ◽  
Earth Abundant ◽  
Semiconductor Heterojunctions ◽  
Photocatalytic H2 Generation ◽  
Hexagonal Nanoplates

Photocatalytic water-splitting with Z-scheme semiconductor heterojunctions is a promising way to achieve renewable solar fuels. Nevertheless, developing earth-abundant direct Z-scheme photocatalytic systems for efficient H2 production is still under-developed. In...

Hydrogen Production Through Two-Step Water Splitting Using YSZ (Ni,Fe) System for Solar Hydrogen Production

Solar Energy ◽  
2005 ◽  
Author(s):  
Hideyuki Ishihara ◽  
Hiroshi Kaneko ◽  
Tsutomu Yokoyama ◽  
Akinori Fuse ◽  
Noriko Hasegawa ◽  
...  
Keyword(s):  
Solid Solution ◽  
Hydrogen Production ◽  
Water Splitting ◽  
Gas Flow ◽  
Molar Ratio ◽  
Iron Ions ◽  
Solar Hydrogen ◽  
Solar Hydrogen Production ◽  
Ar Gas ◽  
Splitting Process

The two-step water splitting with the solid solution of YSZ (Yttrium stabilized Zirconia) and Ni-ferrite (NiFe2O4) was studied for solar hydrogen production. The sample of YSZ/Ni-ferrite solid solution was prepared by calcination of the mixture of the YSZ balls and Ni-ferrite (NiFe2O4) powder. The two-step water splitting process composed of O2-releasing reaction (T = 1773K) in Ar gas flow and H2-generation reaction (T = 1473K) in Ar gas and steam flow with the YSZ/Ni-ferrite solid solution were repeated ten times, and the molar ratio of the released O2 gas and the generated H2 gas was nearly equal to 1:2 in each cycle, indicating that the two-step water splitting process proceeded stoichiometrically. The lattice constants of the YSZ/Ni-ferrite solid solution products after each step of the water splitting process were varied, therefore it was assumed that the oxidation and reduction of the iron ions proceeded in the YSZ phase. It is confirmed that the YSZ/Ni-ferrite was the solid solution and reactive ceramics of high thermal stability. The contents of iron ions determined by the atomic absorption spectroscopy indicated that the YSZ/Ni-ferrite solid solution heated at 1773K contained the only 36% of iron loaded initially. The generated O2 gas was 42% of the theoretical yield. These suggest that YSZ/Ni-ferrite solid solution is more effective reactive ceramics which has the ability to split water with concentrated solar heat than Ni-ferrite.

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