Superior Inorganic Ion Cofactors of Tetraborate Species Attaining Highly Efficient Heterogeneous Electrocatalysis for Water Oxidation on Cobalt Oxyhydroxide Nanoparticles
Superior Inorganic Ion Cofactors of Tetraborate Species Attaining Highly Efficient Heterogeneous Electrocatalysis for Water Oxidation on Cobalt Oxyhydroxide Nanoparticles
复制标题
四硼酸盐种类的优异无机离子辅助因子在羟基氧化钴纳米粒子上实现高效多相电催化水氧化
DOI：
10.1021/acsami.7b13817
复制
发表时间：
2017
影响因子：
9.5
通讯作者：
Yagi Masayuki
中科院分区：
文献类型：
--
作者：
Takeuchi Ryouchi;Sato Tetsuya;Tanaka Kou;Aiso Kaoru;Chandra Debraj;Saito Kenji;Yui Tatsuto;Yagi Masayuki
利用CoO（OH）纳米粒子层沉积电极的非均相催化剂，将无机离子辅因子用于电化学水氧化。在pH 9.4的Na_2B_4O_7溶液中，当施加0.94 V vs. Ag/AgCl时，产生了显著的水氧化催化电流，而在相同pH的K_2SO_4溶液中没有催化电流产生. HB_4O_7-和B_4O_7 ~（2-）离子是CoO（OH）层诱导催化活性的关键辅因子.基于Michaelis-Menten型动力学分析了催化电流的Na 2B 4 O 7浓度依赖性，以提供辅因子对活性位点的亲和常数Km= 28 ± 3.6 mM，以及最大催化电流密度Imax= 2.3 ± 0.13 mA cm-2。HB_4O_（7-）和B_4O_（72-）离子的Imax值比以前报道的CO_3 ~（2-）离子的Imax值（1.3mA·cm ~（-2））高1.4倍。这可能是由于HB 4 O 7-和B4 O 72-离子比CO 32-离子更大、构象更灵活，质子从活性中心向质子接受辅因子的转移距离更短。
A heterogeneous catalyst incorporating an inorganic ion cofactor for electrochemical water oxidation was exploited using a CoO(OH) nanoparticle layer-deposited electrode. The significant catalytic current for water oxidation was generated in a Na2B4O7solution at pH 9.4 when applying 0.94 V versus Ag/AgCl in contrast to no catalytic current generation in the K2SO4solution at the same pH. HB4O7–and B4O72–ions were indicated to act as key cofactors for the induced catalytic activity of the CoO(OH) layer. The Na2B4O7concentration dependence of the catalytic current was analyzed based on a Michaelis–Menten-type kinetics to provide an affinity constant of cofactors to the active sites,Km= 28 ± 3.6 mM, and the maximum catalytic current density,Imax= 2.3 ± 0.13 mA cm–2. TheImaxvalue of HB4O7–and B4O72–ions was 1.4 times higher than that (1.3 mA cm–2) for the previously reported case of CO32–ions. This could be explained by the shorter-range proton transfer from the active site to the proton-accepting cofactor because of the larger size and more flexible conformation of HB4O7–and B4O72–ions compared with that of CO32–ions.