Au ⇆ N synergy and N-doping of metal oxide-based photocatalysts
Au ⇆ N synergy and N-doping of metal oxide-based photocatalysts
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DOI：
10.1021/ja802861u
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发表时间：
2008-09-10
影响因子：
15
通讯作者：
Sanz, Javier Fdez.
中科院分区：
文献类型：
--
作者：
Graciani, Jesus;Nambu, Akira;Sanz, Javier Fdez.
二氧化钛的氮掺杂使可见光下水分解和其他反应的光催化活性成为可能。在这里，我们从理论和实验两个方面表明，TiO2 表面上的 Au 预吸附显着增加了氧化物中注入的 N 的可达量。嵌入 N 的稳定是由于电子从 Au 6s 能级向 N 2p 能级转移，这也增加了 Au 表面粘附能。理论计算预测，Au 还可以稳定其他具有光催化活性的金属氧化物（例如 SrTiO3 和 ZnO）中嵌入的 N，从而在氧化物的价带之上或导带之下产生新的态。在实验中，发现 Au/TiNxO2-y 体系比 TiO2、Au/TiO2 或 TiO2-y 体系对水的解离更加活跃。此外，Au/TiNxO2-y表面能够在高温（575-625 K）下通过水煤气变换反应（WGS）催化产氢，其催化活性优于纯铜（WGS中最活跃的金属催化剂）或ZnO负载的Cu纳米粒子。
N-doping of titania makes photocatalytic activity possible for the splitting of water, and other reactions, under visible light. Here, we show from both theory and experiment that Au preadsorption on TiO2 surfaces significantly increases the reachable amount of N implanted in the oxide. The stabilization of the embedded N is due to an electron transfer from the Au 6s levels toward the N 2p levels, which also increases the Au-surface adhesion energy. Theoretical calculations predict that Au can also stabilize embedded N in other metal oxides with photocatalytic activity, such as SrTiO3 and ZnO, producing new states above the valence band or below the conduction band of the oxide. In experiments, the Au/TiNxO2-y system was found to be more active for the dissociation of water than TiO2, Au/TiO2, or TiO2-y. Furthermore, the Au/TiNxO2-y surfaces were able to catalyze the production of hydrogen through the water-gas shift reaction (WGS) at elevated temperatures (575-625 K), displaying a catalytic activity superior to that of pure copper (the most active metal catalysts for the WGS) or Cu nanoparticles supported on ZnO.