Analysis of catalytic water oxidation by cis-tetraamminedichlororuthenium(III) complex incorporated in a polymer membrane
Analysis of catalytic water oxidation by cis-tetraamminedichlororuthenium(III) complex incorporated in a polymer membrane
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DOI：
10.1021/jp991776t
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发表时间：
2000-05-04
影响因子：
3.3
通讯作者：
Kaneko, M
中科院分区：
文献类型：
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作者：
Yagi, M;Sukegawa, N;Kaneko, M
顺式四胺二氯钌（III）(顺式-[Ru(NH3)（4)Cl-2](+)）配合物是一种非常活跃的水氧化催化剂，可以在水溶液和Nafion膜中析出二氧（O-2）。初始O-2演化速率（V-o2, (mol s(-1))）与溶液和膜中的络合物浓度均为一级。催化剂经过双分子分解，在高络合物浓度下失活。通过动力学分析，得到了O-2反应的一级速率常数k(o2) （s(-1)）和双分子分解的二级速率常数k(deact) (dm(3) mol（-1) s(-1)）。Nafion膜中的k(o2) (1.4 × 10（-2) s(-1)）远高于溶液中的k(o2) (2.3 × 10（-3) s(-1)）。膜中的k(deact) (5.1 × 10(-1) dm(3) mol（-1) s(-1)）略高于溶液中的k(deact) (2.0 × 10(-1) dm(3) mol(-1) s(-1))(-1))，根据分子间距离分布，根据固有活性(k(o2) （s(-1)）和临界分解距离(r（d) (nm)）对Nafion膜的催化活性进行分析，得到k(o2) = 1.5 × 10(-2) s（-1）和r(d) = 0.88 nm。将k（o2）与先前的[Ru(NH3)(6)]（3+）和[Ru(NH3)(5)Cl]（2+）的结果进行了比较；k (o2)复合物的顺序是顺式[俄文(NH3) (4) Cl-2](+) >[俄文(NH3) (5) Cl](2 +) >[俄文(NH3)(6)](3 +)。讨论了结构对催化活性的影响。
cis-Tetraamminedichlororuthenium(III) (cis-[Ru(NH3)(4)Cl-2](+)) complex was found to work as a very active water oxidation catalyst to evolve dioxygen (O-2) in an aqueous solution as well as in a Nafion membrane. The initial O-2 evolution rate (V-o2, (mol s(-1))) was first-order with respect to the complex concentration in both the solution and membrane. The catalyst undergoes a bimolecular decomposition to deactivate at high complex concentrations. The first-order rate constant (k(o2) (s(-1))) for O-2 evolution and the second-order rate constant (k(deact) (dm(3) mol(-1) s(-1))) for bimolecular decomposition were obtained from the kinetic analysis based on the competition between both processes. The k(o2) (1.4 x 10(-2) s(-1)) in the Nafion membrane is much higher than that (2.3 x 10(-3) s(-1)) in the solution. The k(deact) (5.1 x 10(-1) dm(3) mol(-1) s(-1)) in the membrane was slightly higher than that (2.0 x 10(-1) dm(3) mol(-1) s(-1)) in the solution, The catalytic activity in the Nafion membrane was analyzed in terms of the intrinsic activity (k(o2) (s(-1))) and critical decomposition distance (r(d) (nm)) on the basis of the intermolecular distance distribution to obtain k(o2) = 1.5 x 10(-2) s(-1) and r(d) = 0.88 nm. The k(o2) was compared with the earlier results on [Ru(NH3)(6)](3+) and [Ru(NH3)(5)Cl](2+); the k(o2) of the complexes was in the order cis-[Ru(NH3)(4)Cl-2](+) > [Ru(NH3)(5)Cl](2+) > [Ru(NH3)(6)](3+). The structural effect on the catalytic activity was discussed.