Enhanced photocatalytic N2 fixation via defective and fluoride modified TiO2 surface

Photocatalytic N-2 fixation (PNF) provides a low-cost route to generate ammonia. The poor conversion efficiency from photon to ammonia seriously hinders the step forward because of the low concentration of N-2 molecules. Herein, we demonstrate a photocatalyst with surface oxygen vacancies (Vo) and a F modified surface to facilitate N-2 adsorption and activation on the surface of catalysts. The Vo site promotes the chemical adsorption of N-2, electron transfer from catalyst to N-2. F modification switches the TiO2 surface properties from hydrophilic to aerophilic, thus facilitating the adsorption of N-2. Meanwhile, the hydrogen reduction reaction (HER) is sup-pressed, as protons hard to adsorb on F capped surfaces. The optimal NH3 production rate can reach 206 mu molh(-1)g(-1), which is similar to 9 times higher than that of pure TiO2 nanoparticles (similar to 23 mu molh(-1)g(-1)). This report provides a potential strategy to overcome mass transfer limitation and achieve a high conversion efficiency in PNF.

Automated summary

The research utilizes a photocatalyst with surface oxygen vacancies and F modified surface to enhance N-2 adsorption and activation, achieving higher efficiency in generating ammonia.