Department of Chemistry and ‡Emerson Center for Scientific Computation, Emory University , 1515 Dickey Dr., Atlanta, Georgia 30322, United States .
J Am Chem Soc. 2014 Jul 2;136(26):9268-71. doi: 10.1021/ja5045488. Epub 2014 Jun 20.
An all-inorganic, oxidatively and thermally stable, homogeneous water oxidation catalyst based on redox-active (vanadate(V)-centered) polyoxometalate ligands, Na10[Co4(H2O)2(VW9O34)2]·35H2O (Na101-V2, sodium salt of the polyanion 1-V2), was synthesized, thoroughly characterized and shown to catalyze water oxidation in dark and visible-light-driven conditions. This synthetic catalyst is exceptionally fast under mild conditions (TOF > 1 × 10(3) s(-1)). Under light-driven conditions using Ru(bpy)3 as a photosensitizer and persulfate as a sacrificial electron acceptor, 1-V2 exhibits higher selectivity for water oxidation versus bpy ligand oxidation, the final O2 yield by 1-V2 is twice as high as that of using Co4(H2O)2(PW9O34)2 (1-P2), and the quantum efficiency of O2 formation at 6.0 μM 1-V2 reaches ∼68%. Multiple experimental results (e.g., UV-vis absorption, FT-IR, (51)V NMR, dynamic light scattering, tetra-n-heptylammonium nitrate-toluene extraction, effect of pH, buffer, and buffer concentration, etc.) confirm that the polyanion unit (1-V2) itself is the dominant active catalyst and not Co(2+)(aq) or cobalt oxide.
一种基于氧化还原活性（钒中心）多金属氧酸盐配体的全无机、氧化和热稳定、均相水氧化催化剂，Na10[Co4(H2O)2(VW9O34)2]·35H2O（Na101-V2，多阴离子 1-V2 的钠盐），已被合成、彻底表征，并被证明可在黑暗和可见光驱动条件下催化水氧化。该合成催化剂在温和条件下非常快速（TOF>1×10(3)s(-1)）。在以Ru(bpy)3作为光敏剂和过硫酸盐作为牺牲电子受体的光驱动条件下，1-V2 对水氧化相对于 bpy 配体氧化具有更高的选择性，1-V2 的最终 O2 产率是使用Co4(H2O)2(PW9O34)2（1-P2）的两倍，并且在 6.0 μM 1-V2 时 O2 形成的量子效率达到约 68%。多项实验结果（例如，UV-vis 吸收、FT-IR、(51)V NMR、动态光散射、四正庚基硝酸铵-甲苯萃取、pH 值、缓冲液和缓冲液浓度等的影响）证实多阴离子单元（1-V2）本身是主要的活性催化剂，而不是 Co(2+)(aq)或氧化钴。
