The Experts below are selected from a list of 79659 Experts worldwide ranked by ideXlab platform
Shunichi Fukuzumi - One of the best experts on this subject based on the ideXlab platform.
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photocatalytic Hydrogen Evolution from carbon neutral oxalate with 2 phenyl 4 1 naphthyl quinolinium ion and metal nanoparticles
Physical Chemistry Chemical Physics, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution has been made possible by using oxalate as a carbon-neutral electron source, metal nanoparticles as Hydrogen-Evolution catalysts and the 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA), which forms the long-lived electron-transfer state upon photoexcitation, as a photocatalyst. The Hydrogen Evolution was conducted in a deaerated mixed solution of an aqueous buffer and acetonitrile (MeCN) [1 : 1 (v/v)] by photoirradiation (λ > 340 nm). The gas evolved during the photocatalytic reaction contained H2 and CO2 in a molar ratio of 1 : 2, indicating that oxalate acts as a two-electron donor. The Hydrogen yield based on the amount of oxalate reached more than 80% under pH conditions higher than 6. Ni and Ru nanoparticles as well as Pt nanoparticles act as efficient Hydrogen-Evolution catalysts in the photocatalytic Hydrogen Evolution. The photocatalyst for Hydrogen Evolution can be used several times without significant deactivation of the catalytic activity. Nanosecond laser flash photolysis measurements have revealed that electron transfer from oxalate to the photogenerated QuPh˙–NA˙+, which forms a π-dimer radical cation with QuPh+−NA [(QuPh˙–NA˙+)(QuPh+–NA)], occurs followed by subsequent electron transfer from QuPh˙–NA to the Hydrogen-Evolution catalyst in the photocatalytic Hydrogen Evolution. Oxalate acts as an efficient electron source under a wide range of reaction conditions.
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photocatalytic Hydrogen Evolution with ni nanoparticles by using 2 phenyl 4 1 naphthyl quinolinium ion as a photocatalyst
Energy and Environmental Science, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Hiroaki Kotani, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution with 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA) as a photocatalyst and dihydronicotinamide adenine dinucleotide (NADH) as a sacrificial electron donor has been made possible for the first time by using nickel nanoparticles (NiNPs) as a non-precious metal catalyst. The Hydrogen Evolution rate with the most active Ni nanoparticles (hexagonal close-packed (hcp) structure, 6.6 nm) examined here was 40% of that with commercially available Pt nanoparticles (2 nm) using the same catalyst weight. The catalytic activity of NiNPs depends not only on their sizes but also on their crystal phases. The Hydrogen-Evolution rate normalized by the catalyst weight increased as the size of NiNPs becomes smaller, with regard to the crystal phase, the Hydrogen-Evolution rate of the NiNPs with hcp structure is more than 4 times higher than the rate of the NiNPs with face-centred cubic (fcc) structure of similar size. NiNPs act as the Hydrogen-Evolution catalyst under the pH conditions between 4.5 and 8.0, although the Hydrogen-Evolution rate at pH > 7.0 was much lower as compared with the Hydrogen-Evolution rate at pH 4.5. A kinetic study revealed that the rate of electron transfer from photogenerated QuPh˙–NA to NiNPs was much higher than the rate of Hydrogen Evolution, indicating that the rate-determining step may be proton reduction or desorption of Hydrogen.
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efficient photocatalytic Hydrogen Evolution without an electron mediator using a simple electron donor acceptor dyad
Physical Chemistry Chemical Physics, 2007Co-Authors: Hiroaki Kotani, Kei Ohkubo, Toshiya Ono, Shunichi FukuzumiAbstract:A highly efficient photocatalytic Hydrogen Evolution system without an electron mediator such as methyl viologen (MV2+) has been constructed using 9-mesityl-10-methylacridinium ion (Acr+–Mes), poly(N-vinyl-2-pyrrolidone)-protected platinum nanoclusters (Pt–PVP) and NADH (β-nicotinamide adenine dinucleotide, reduced form) as the photocatalyst, Hydrogen Evolution catalyst and electron donor, respectively. The photocatalyst (Acr+–Mes) undergoes photoinduced electron transfer (ET) from the Mes moiety to the singlet excited state of the Acr+ moiety to produce an extremely long-lived ET state, which is capable of oxidizing NADH and reducing Pt–PVP, leading to efficient Hydrogen Evolution. The Hydrogen Evolution efficiency is 300 times higher than that in the presence of MV2+ because of the much faster reduction rate of Pt–PVP by Acr˙–Mes compared with that by MV˙+. When the electron donor (NADH) is replaced by ethanol in the presence of an alcohol deHydrogenase (ADH), NADH is regenerated during the photocatalytic Hydrogen Evolution.
Yusuke Yamada - One of the best experts on this subject based on the ideXlab platform.
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photocatalytic Hydrogen Evolution from carbon neutral oxalate with 2 phenyl 4 1 naphthyl quinolinium ion and metal nanoparticles
Physical Chemistry Chemical Physics, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution has been made possible by using oxalate as a carbon-neutral electron source, metal nanoparticles as Hydrogen-Evolution catalysts and the 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA), which forms the long-lived electron-transfer state upon photoexcitation, as a photocatalyst. The Hydrogen Evolution was conducted in a deaerated mixed solution of an aqueous buffer and acetonitrile (MeCN) [1 : 1 (v/v)] by photoirradiation (λ > 340 nm). The gas evolved during the photocatalytic reaction contained H2 and CO2 in a molar ratio of 1 : 2, indicating that oxalate acts as a two-electron donor. The Hydrogen yield based on the amount of oxalate reached more than 80% under pH conditions higher than 6. Ni and Ru nanoparticles as well as Pt nanoparticles act as efficient Hydrogen-Evolution catalysts in the photocatalytic Hydrogen Evolution. The photocatalyst for Hydrogen Evolution can be used several times without significant deactivation of the catalytic activity. Nanosecond laser flash photolysis measurements have revealed that electron transfer from oxalate to the photogenerated QuPh˙–NA˙+, which forms a π-dimer radical cation with QuPh+−NA [(QuPh˙–NA˙+)(QuPh+–NA)], occurs followed by subsequent electron transfer from QuPh˙–NA to the Hydrogen-Evolution catalyst in the photocatalytic Hydrogen Evolution. Oxalate acts as an efficient electron source under a wide range of reaction conditions.
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photocatalytic Hydrogen Evolution with ni nanoparticles by using 2 phenyl 4 1 naphthyl quinolinium ion as a photocatalyst
Energy and Environmental Science, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Hiroaki Kotani, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution with 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA) as a photocatalyst and dihydronicotinamide adenine dinucleotide (NADH) as a sacrificial electron donor has been made possible for the first time by using nickel nanoparticles (NiNPs) as a non-precious metal catalyst. The Hydrogen Evolution rate with the most active Ni nanoparticles (hexagonal close-packed (hcp) structure, 6.6 nm) examined here was 40% of that with commercially available Pt nanoparticles (2 nm) using the same catalyst weight. The catalytic activity of NiNPs depends not only on their sizes but also on their crystal phases. The Hydrogen-Evolution rate normalized by the catalyst weight increased as the size of NiNPs becomes smaller, with regard to the crystal phase, the Hydrogen-Evolution rate of the NiNPs with hcp structure is more than 4 times higher than the rate of the NiNPs with face-centred cubic (fcc) structure of similar size. NiNPs act as the Hydrogen-Evolution catalyst under the pH conditions between 4.5 and 8.0, although the Hydrogen-Evolution rate at pH > 7.0 was much lower as compared with the Hydrogen-Evolution rate at pH 4.5. A kinetic study revealed that the rate of electron transfer from photogenerated QuPh˙–NA to NiNPs was much higher than the rate of Hydrogen Evolution, indicating that the rate-determining step may be proton reduction or desorption of Hydrogen.
Kei Ohkubo - One of the best experts on this subject based on the ideXlab platform.
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photocatalytic Hydrogen Evolution from carbon neutral oxalate with 2 phenyl 4 1 naphthyl quinolinium ion and metal nanoparticles
Physical Chemistry Chemical Physics, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution has been made possible by using oxalate as a carbon-neutral electron source, metal nanoparticles as Hydrogen-Evolution catalysts and the 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA), which forms the long-lived electron-transfer state upon photoexcitation, as a photocatalyst. The Hydrogen Evolution was conducted in a deaerated mixed solution of an aqueous buffer and acetonitrile (MeCN) [1 : 1 (v/v)] by photoirradiation (λ > 340 nm). The gas evolved during the photocatalytic reaction contained H2 and CO2 in a molar ratio of 1 : 2, indicating that oxalate acts as a two-electron donor. The Hydrogen yield based on the amount of oxalate reached more than 80% under pH conditions higher than 6. Ni and Ru nanoparticles as well as Pt nanoparticles act as efficient Hydrogen-Evolution catalysts in the photocatalytic Hydrogen Evolution. The photocatalyst for Hydrogen Evolution can be used several times without significant deactivation of the catalytic activity. Nanosecond laser flash photolysis measurements have revealed that electron transfer from oxalate to the photogenerated QuPh˙–NA˙+, which forms a π-dimer radical cation with QuPh+−NA [(QuPh˙–NA˙+)(QuPh+–NA)], occurs followed by subsequent electron transfer from QuPh˙–NA to the Hydrogen-Evolution catalyst in the photocatalytic Hydrogen Evolution. Oxalate acts as an efficient electron source under a wide range of reaction conditions.
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photocatalytic Hydrogen Evolution with ni nanoparticles by using 2 phenyl 4 1 naphthyl quinolinium ion as a photocatalyst
Energy and Environmental Science, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Hiroaki Kotani, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution with 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA) as a photocatalyst and dihydronicotinamide adenine dinucleotide (NADH) as a sacrificial electron donor has been made possible for the first time by using nickel nanoparticles (NiNPs) as a non-precious metal catalyst. The Hydrogen Evolution rate with the most active Ni nanoparticles (hexagonal close-packed (hcp) structure, 6.6 nm) examined here was 40% of that with commercially available Pt nanoparticles (2 nm) using the same catalyst weight. The catalytic activity of NiNPs depends not only on their sizes but also on their crystal phases. The Hydrogen-Evolution rate normalized by the catalyst weight increased as the size of NiNPs becomes smaller, with regard to the crystal phase, the Hydrogen-Evolution rate of the NiNPs with hcp structure is more than 4 times higher than the rate of the NiNPs with face-centred cubic (fcc) structure of similar size. NiNPs act as the Hydrogen-Evolution catalyst under the pH conditions between 4.5 and 8.0, although the Hydrogen-Evolution rate at pH > 7.0 was much lower as compared with the Hydrogen-Evolution rate at pH 4.5. A kinetic study revealed that the rate of electron transfer from photogenerated QuPh˙–NA to NiNPs was much higher than the rate of Hydrogen Evolution, indicating that the rate-determining step may be proton reduction or desorption of Hydrogen.
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efficient photocatalytic Hydrogen Evolution without an electron mediator using a simple electron donor acceptor dyad
Physical Chemistry Chemical Physics, 2007Co-Authors: Hiroaki Kotani, Kei Ohkubo, Toshiya Ono, Shunichi FukuzumiAbstract:A highly efficient photocatalytic Hydrogen Evolution system without an electron mediator such as methyl viologen (MV2+) has been constructed using 9-mesityl-10-methylacridinium ion (Acr+–Mes), poly(N-vinyl-2-pyrrolidone)-protected platinum nanoclusters (Pt–PVP) and NADH (β-nicotinamide adenine dinucleotide, reduced form) as the photocatalyst, Hydrogen Evolution catalyst and electron donor, respectively. The photocatalyst (Acr+–Mes) undergoes photoinduced electron transfer (ET) from the Mes moiety to the singlet excited state of the Acr+ moiety to produce an extremely long-lived ET state, which is capable of oxidizing NADH and reducing Pt–PVP, leading to efficient Hydrogen Evolution. The Hydrogen Evolution efficiency is 300 times higher than that in the presence of MV2+ because of the much faster reduction rate of Pt–PVP by Acr˙–Mes compared with that by MV˙+. When the electron donor (NADH) is replaced by ethanol in the presence of an alcohol deHydrogenase (ADH), NADH is regenerated during the photocatalytic Hydrogen Evolution.
Takamitsu Miyahigashi - One of the best experts on this subject based on the ideXlab platform.
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photocatalytic Hydrogen Evolution from carbon neutral oxalate with 2 phenyl 4 1 naphthyl quinolinium ion and metal nanoparticles
Physical Chemistry Chemical Physics, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution has been made possible by using oxalate as a carbon-neutral electron source, metal nanoparticles as Hydrogen-Evolution catalysts and the 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA), which forms the long-lived electron-transfer state upon photoexcitation, as a photocatalyst. The Hydrogen Evolution was conducted in a deaerated mixed solution of an aqueous buffer and acetonitrile (MeCN) [1 : 1 (v/v)] by photoirradiation (λ > 340 nm). The gas evolved during the photocatalytic reaction contained H2 and CO2 in a molar ratio of 1 : 2, indicating that oxalate acts as a two-electron donor. The Hydrogen yield based on the amount of oxalate reached more than 80% under pH conditions higher than 6. Ni and Ru nanoparticles as well as Pt nanoparticles act as efficient Hydrogen-Evolution catalysts in the photocatalytic Hydrogen Evolution. The photocatalyst for Hydrogen Evolution can be used several times without significant deactivation of the catalytic activity. Nanosecond laser flash photolysis measurements have revealed that electron transfer from oxalate to the photogenerated QuPh˙–NA˙+, which forms a π-dimer radical cation with QuPh+−NA [(QuPh˙–NA˙+)(QuPh+–NA)], occurs followed by subsequent electron transfer from QuPh˙–NA to the Hydrogen-Evolution catalyst in the photocatalytic Hydrogen Evolution. Oxalate acts as an efficient electron source under a wide range of reaction conditions.
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photocatalytic Hydrogen Evolution with ni nanoparticles by using 2 phenyl 4 1 naphthyl quinolinium ion as a photocatalyst
Energy and Environmental Science, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Hiroaki Kotani, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution with 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA) as a photocatalyst and dihydronicotinamide adenine dinucleotide (NADH) as a sacrificial electron donor has been made possible for the first time by using nickel nanoparticles (NiNPs) as a non-precious metal catalyst. The Hydrogen Evolution rate with the most active Ni nanoparticles (hexagonal close-packed (hcp) structure, 6.6 nm) examined here was 40% of that with commercially available Pt nanoparticles (2 nm) using the same catalyst weight. The catalytic activity of NiNPs depends not only on their sizes but also on their crystal phases. The Hydrogen-Evolution rate normalized by the catalyst weight increased as the size of NiNPs becomes smaller, with regard to the crystal phase, the Hydrogen-Evolution rate of the NiNPs with hcp structure is more than 4 times higher than the rate of the NiNPs with face-centred cubic (fcc) structure of similar size. NiNPs act as the Hydrogen-Evolution catalyst under the pH conditions between 4.5 and 8.0, although the Hydrogen-Evolution rate at pH > 7.0 was much lower as compared with the Hydrogen-Evolution rate at pH 4.5. A kinetic study revealed that the rate of electron transfer from photogenerated QuPh˙–NA to NiNPs was much higher than the rate of Hydrogen Evolution, indicating that the rate-determining step may be proton reduction or desorption of Hydrogen.
Hiroaki Kotani - One of the best experts on this subject based on the ideXlab platform.
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photocatalytic Hydrogen Evolution with ni nanoparticles by using 2 phenyl 4 1 naphthyl quinolinium ion as a photocatalyst
Energy and Environmental Science, 2012Co-Authors: Yusuke Yamada, Shunichi Fukuzumi, Hiroaki Kotani, Kei Ohkubo, Takamitsu MiyahigashiAbstract:Photocatalytic Hydrogen Evolution with 2-phenyl-4-(1-naphthyl)quinolinium ion (QuPh+–NA) as a photocatalyst and dihydronicotinamide adenine dinucleotide (NADH) as a sacrificial electron donor has been made possible for the first time by using nickel nanoparticles (NiNPs) as a non-precious metal catalyst. The Hydrogen Evolution rate with the most active Ni nanoparticles (hexagonal close-packed (hcp) structure, 6.6 nm) examined here was 40% of that with commercially available Pt nanoparticles (2 nm) using the same catalyst weight. The catalytic activity of NiNPs depends not only on their sizes but also on their crystal phases. The Hydrogen-Evolution rate normalized by the catalyst weight increased as the size of NiNPs becomes smaller, with regard to the crystal phase, the Hydrogen-Evolution rate of the NiNPs with hcp structure is more than 4 times higher than the rate of the NiNPs with face-centred cubic (fcc) structure of similar size. NiNPs act as the Hydrogen-Evolution catalyst under the pH conditions between 4.5 and 8.0, although the Hydrogen-Evolution rate at pH > 7.0 was much lower as compared with the Hydrogen-Evolution rate at pH 4.5. A kinetic study revealed that the rate of electron transfer from photogenerated QuPh˙–NA to NiNPs was much higher than the rate of Hydrogen Evolution, indicating that the rate-determining step may be proton reduction or desorption of Hydrogen.
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efficient photocatalytic Hydrogen Evolution without an electron mediator using a simple electron donor acceptor dyad
Physical Chemistry Chemical Physics, 2007Co-Authors: Hiroaki Kotani, Kei Ohkubo, Toshiya Ono, Shunichi FukuzumiAbstract:A highly efficient photocatalytic Hydrogen Evolution system without an electron mediator such as methyl viologen (MV2+) has been constructed using 9-mesityl-10-methylacridinium ion (Acr+–Mes), poly(N-vinyl-2-pyrrolidone)-protected platinum nanoclusters (Pt–PVP) and NADH (β-nicotinamide adenine dinucleotide, reduced form) as the photocatalyst, Hydrogen Evolution catalyst and electron donor, respectively. The photocatalyst (Acr+–Mes) undergoes photoinduced electron transfer (ET) from the Mes moiety to the singlet excited state of the Acr+ moiety to produce an extremely long-lived ET state, which is capable of oxidizing NADH and reducing Pt–PVP, leading to efficient Hydrogen Evolution. The Hydrogen Evolution efficiency is 300 times higher than that in the presence of MV2+ because of the much faster reduction rate of Pt–PVP by Acr˙–Mes compared with that by MV˙+. When the electron donor (NADH) is replaced by ethanol in the presence of an alcohol deHydrogenase (ADH), NADH is regenerated during the photocatalytic Hydrogen Evolution.
