Interesting molecule adsorption strategy induced energy band tuning: Boosts 43 times photocatalytic Water splitting ability for commercial TiO2

Abstract

The photogenerated electron reduction ability and light absorption capacity of photocatalysts are crucial to their photocatalytic hydrogen evolution performance. However, rising the conduction band position will widen the band gap and result in a decrease in light absorption efficiency. Herein, an ultra-simple and novel organic molecule adsorption strategy was carried out on the surface of commercial TiO2 to simultaneously increase the reduction ability of photogenerated electrons and light absorption of commercial TiO2. Then the contradiction mentioned above was perfectly solved by such an interesting strategy. The resultant ethylenediamine adsorbed TiO2 exhibits excellent photocatalytic hydrogen evolution rate, which is 43 times higher than that of commercial TiO2. Effectively, the experimental results and DFT theoretical calculations verified that the adsorbed organic molecule can provide electrons for TiO2. The provided electrons enable the conduction band bend upwards, thus enhance the reduction ability of photogenerated electrons and improve the light absorption ability of TiO2. More interestingly, the provided electrons can also promote the separation efficiency of photogenerated carriers by weakening the attraction of photogenerated holes to photogenerated electrons. Therefore, the efficiency of photocatalytic hydrogen production has been greatly improved. This work opens a new research field to enhance the photocatalytic performance by adsorbing various designed organics on the surface of photocatalysts.