Development of photocatalysts based on solid solutions of oxides and sulfides for water splitting under visible light irradiation

开发基于氧化物和硫化物固溶体的可见光照射下分解水光催化剂

• 批准号: 11640601
• 负责人: KUDO Akihiko
• 金额: $ 2.3万
• 依托单位: SCIENCE UNIVERSITY OF TOKYO
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640601/
• 关键词: Photocatalyst; Water splitting; Visible light response; Hydrogen evolution; Oxygen evolution; Tantalate; Bismuth vanadate; Zine sulfide; タンタル酸ナトリウム; ランタン; ドーピング; タンタル酸ストロンチウム; ニオブ酸ストロンチウム

Various metal tantalates showed activities for water splitting into H_2 and O_2 in stoichiometric amounts under UV irradiation. Among them, LiTaO_3, NaTaO_3, SrTa_2O_6, Sr_2Ta_2O_7, and BaTa_2O_6 were highly active. Especially, NiO(0.05wt%)/NaTaO_3 was the most active and showed 20% of a quantum yield at 270 nm. The activity for water splitting over the NiO/NaTaO_3 photocatalyst was much improved by lanthanide (La, Pr, Nd, Sm, Gd, Tb, and Dy)-doping into NaTaO_3. Lanthanum was the most effective dopant. The quantum yield at 270 nm amounted ca. 50%. Moreover, deactivation which was observed for a non-doped NiO/NaTaO_3 photocatalyst was much suppressed. SEM observation suggested that these effects were mainly due to the decrease in the particle size and characteristic step structure created by the Ln-doping.Scheelite monoclinic BiVO_4 which was synthesized by a soft solution process at room temperature showed a high activity for O_2 evolution from AgNO_<3aq> under visible light irradiation (quantum yield=9% at 450 nm).Zn_<0.999>Ni_<0.001>S photocatalysts (energy gap = 2.3 eV) heat-treated at 773 K in an N_2 flow showed the activity for hydrogen evolution from aqueous solutions containing K_2SO_3 and Na_2S as reducing reagents under visible light irradiation without co-catalysts such as Pt.

各种金属钽酸盐在紫外线照射下表现出化学计量的水分解成H_2和O_2的活性。其中LiTaO_3、NaTaO_3、SrTa_2O_6、Sr_2Ta_2O_7和BaTa_2O_6的活性较高。特别是，NiO(0.05wt%)/NaTaO_3最活跃，在270 nm处显示出20%的量子产率。通过在NaTaO_3中掺杂镧系元素（La、Pr、Nd、Sm、Gd、Tb和Dy），NiO/NaTaO_3光催化剂的水分解活性大大提高。镧是最有效的掺杂剂。 270 nm 处的量子产率约为50%。此外，对于未掺杂的NiO/NaTaO_3光催化剂观察到的失活被大大抑制。 SEM观察表明这些效应主要是由于Ln掺杂产生的颗粒尺寸和特征阶梯结构的减小所致。室温软溶液法合成的白钨矿单斜BiVO_4表现出较高的从AgNO_析出O_2的活性<3aq>在可见光照射下（量子产率=9% at 450 nm）。Zn_<0.999>Ni_<0.001>S光催化剂（能隙= 2.3 eV)在N_2流中773 K下热处理显示出在可见光照射下，在没有Pt等助催化剂的情况下，从含有K_2SO_3和Na_2S作为还原剂的水溶液中析氢的活性。

项目成果

H.Kato and A.Kudo: "Water Splitting into H_2 and O_2 on Alkali Tantalate Photocatalysts ATaO_3 (A: Li,Na, and K)"J.Phys. Chem.. (印刷中).

H.Kato 和 A.Kudo：“碱性钽酸盐光催化剂 ATaO_3（A：Li、Na 和 K）上的水分解成 H_2 和 O_2”J.Phys.（正在出版）。

A.Kudo,H.Kato,and S.Nakagawa: "Water Splitting into H_2 and O_2 on New Sr_2M_2O_7 (M=Nb and Ta) Photocatalysts with Layere Perovskite Structures-Factors Affecting the Photocatalytic Activit-"J.Phys.Chem.. 104・3. 571-575 (2000)

A.Kudo、H.Kato 和 S.Nakakawa：“具有层状钙钛矿结构的新型 Sr_2M_2O_7（M=Nb 和 Ta）光催化剂上水分解成 H_2 和 O_2 - 影响光催化活性的因素 -”J.Phys.Chem.. 104・3。571-575（2000）

工藤昭彦: "水の完全光分解のための希土類を構成元素とする光触媒材料"希土類. 37号. 29-46 (2000)

工藤明彦：“含有稀土元素的光催化材料用于完全光解水”《稀土》37 No. 29-46 (2000)。

H.Kato and A.Kudo: "Photocatalytic Decomposition of Pure Water into H_2 and O_2 over SrTa_2O_6 Prepared by a Flux Method"Chem.Lett.. 1207-1208 (1999)

H.Kato 和 A.Kudo：“通过助熔剂法制备的 SrTa_2O_6 上光催化分解纯水为 H_2 和 O_2”Chem.Lett.1207-1208 (1999)

A.Kudo,K.Omori,and H.Kato: "A Novel Aqueous Process for Preparation of Crystal Form-Controlled and Highly Crystalline BiVO_4 Powder from Layered Vanadates at Room Temperature and its Photocatalytic and Photophysical Properties"J.Am.Chem.Soc.. 121・49. 1145

A.Kudo、K.Omori 和 H.Kato：“室温下由层状钒酸盐制备晶型控制的高结晶 BiVO_4 粉末的新型水相工艺及其光催化和光物理性能”J.Am.Chem.Soc .. 121・49.