Kotani Hiroaki, Ono Toshiya, Ohkubo Kei, Fukuzumi Shunichi
Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan.
Phys Chem Chem Phys. 2007 Mar 28;9(12):1487-92. doi: 10.1039/b612794k. Epub 2006 Nov 13.
A highly efficient photocatalytic hydrogen evolution system without an electron mediator such as methyl viologen (MV(2+)) has been constructed using 9-mesityl-10-methylacridinium ion (Acr(+)-Mes), poly(N-vinyl-2-pyrrolidone)-protected platinum nanoclusters (Pt-PVP) and NADH (beta-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 MV(2+) 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.
已构建了一种高效的光催化析氢系统，该系统不使用诸如甲基紫精（MV(2+)）之类的电子媒介体，而是分别使用9-均三甲苯基-10-甲基吖啶离子（Acr(+)-Mes）、聚（N-乙烯基-2-吡咯烷酮）保护的铂纳米团簇（Pt-PVP）和NADH（β-烟酰胺腺嘌呤二核苷酸，还原型）作为光催化剂、析氢催化剂和电子供体。光催化剂（Acr(+)-Mes）经历从Mes部分到Acr(+)部分单重激发态的光诱导电子转移（ET），以产生极长寿命的ET态，该态能够氧化NADH并还原Pt-PVP，从而实现高效析氢。由于与MV(+)相比，Acr()-Mes对Pt-PVP的还原速率快得多，析氢效率比存在MV(2+)时高300倍。当在醇脱氢酶（ADH）存在的情况下，电子供体（NADH）被乙醇替代时，在光催化析氢过程中NADH得以再生。
