Development of visible-light-driven photocatalysts via an interfacial photoexcitation process

我们目前的发现表明，我们可以通过简单的表面修饰来控制p-(阴极光响应)或n型(阳极光响应)电导率，而不是复杂的晶体结构修改。研究了紫外光和可见光照射下三电极光电化学燃料制备体系中的界面电荷转移(IFCT)。在本研究中，我们研究了Cu(II)/TiO2光电极，并观察到了阴极光响应。在Cu(II)/TiO2光阴极和铂片上分别检测到H2和O2的析出，表明在没有添加任何牺牲剂的情况下，水发生了裂解反应。考虑到IFCT的概念，从TiO2价带到铜(II)纳米团簇的直接电子激发引发了水的裂解反应。另一方面，Cr(III)/SrTiO_3光电极表现出阳极光响应，表明在这种光阳极上发生了析氧反应，在这种情况下，电子被从Cr(III)纳米团簇直接激发到SrTiO_3的导带(反向转移路径)。我们期待这项研究将有希望进一步研究直接界面电荷转移，不仅用于光催化剂，而且还用于其他应用。

Our current findings imply that we can control p- (cathodic photoresponse) or n-type (anodic photoresponse) conductivity by a facile surface modification, instead of complicated crystal structure modifications. We have studied interfacial charge transfer (IFCT) in three-electrode photoelectrochemical system for fuel production under UV and visible-light illumination. In this study, we have investigated Cu(II)/TiO2 photo-electrode, and cathodic photoresponse was observed. H2 and O2 evolution were detected from Cu(II)/TiO2 photocathode and Pt sheet, respectively, indicating that water splitting reaction occurred without any addition of sacrificial agent. Considering the concept of IFCT, a direct electron excitation from the valence band of TiO2 to Cu(II) nanoclusters initiated water splitting reaction. On the other hand, Cr(III)/SrTiO3 photo-electrode exhibited anodic photoresponse, indicating that O2 evolution took place on this photoanode; in this case, electrons were directly excited from Cr(III) nanoclusters to the conduction band of SrTiO3 (reversed transfer path). We expect this research would be promising to further examine the direct interfacial charge transfer, not only for photocatalyst but also for other applications.