Enhanced photocatalytic nitrogen fixation on Cu2O clusters/MIL-100(Fe) heterojunction

A series of Cu2O clusters/MIL-100(Fe) heterojunctions with different Cu2O mass ratios were constructed as the photocatalysts for N2 fixation. An optimal nitrogen fixation performance of 51.22 μmol·g−1·h−1 is achieved when the mass fraction of Cu2O is 20 %. Isotope analysis experiments confirmed that the nitrogen source is N2. Possible intermediate signals during photocatalytic reactions were detected by in situ DRIFTS. XPS results further confirm the formation of Cu2O/MIL-100(Fe) heterojunctions, and that the existence of Cu–O surface interactions is the key to efficient electron transfer. It is revealed that the improvement of the catalytic performance is derived from the formation of heterojunction which regulates the energy band structure as well as promotes the separation of photogenerated electron-hole pairs. This study proposes a possible mechanism of photocatalytic nitrogen fixation and emphasizes the role of surface interaction and electron transfer in type-II heterojunction in improving nitrogen fixation performance.