Photoexcitation assisted oxygen vacancy for enhancing nitrogen fixation with Fe-CeO2

Abstract

Photoexcitation assisted oxygen vacancy for enhancing N2 fixation was investigated with Fe-CeO2 as photocatalysts. Fe substituted doping of CeO2 promoted the formation of oxygen vacancies (Vo). 5 % Fe-CeO2 exhibited the highest Vo concentration with photocatalytic nitrogen fixation efficiency of 176 μmol·g−1·h−1. The oxygen vacancy could induce the formation of the oxygen vacancy level, which could reduce the band gap energy, attract electrons, and hinder the electron hole recombination. More importantly, the oxygen vacancy level could be used as a springboard to reduce the energy required for N2 activation. In addition, calcination and acid-wash were used to regulate the concentration of surface oxygen vacancies (Vo-s) and bulk oxygen vacancies (Vo-b), respectively. The results showed that acid-wash only reduced the Vo-s concentration, while calcination reduced both the Vo-s and the Vo-b concentration, and the high concentration of Vo and Vo-s was beneficial for photocatalytic nitrogen fixation. The regulation strategy of Vo had guiding significance for improving the photocatalytic performance of metal oxide photocatalysts.