Fast in situ construction of a Cu2O/Cu-MOF S-scheme heterojunction with synergetic interface matching and carrier separation ability for efficient photocatalytic nitrogen fixation

Metal-organic frameworks (MOFs)-based heterojunctions, as one of porous materials, offer abundant unsaturated coordination sites, making them suitable for photocatalytic N 2 reduction. However, complicated reaction methods, mismatched interfaces and ineffective photo-induced carrier separation restricted their applications. In this study, a kind of Cu 2 O/Cu-MOF heterojunction was synthesized via a fast in situ method in acidic medium (CCM-a). It showed a typical core-shell structure with Cu-MOF coating surrounding the Cu 2 O. The photocatalytic NH 3 yield of CCM-a reached 83.25 μmol/g/h, which was 9.03 and 19.64 higher than that of pure Cu 2 O and CCM-b, respectively. The reaction pathway of N 2 reduction was investigated using density functional theory (DFT) and in-situ FT-IR spectra, revealing a preference for the alternating association pathway. The photocatalytic mechanisms were analyzed through the built-in electric field (IEF) theory, supporting its S-scheme charge-transfer route of CCM-a. The novel material achieved from in situ strategy not only ensured a good interface matching ability but also facilitated sufficient separation of photo-generated carriers via a S-scheme route for efficient photocatalytic N 2 fixation.