Coordination-driven immobilization of his-tagged superoxide dismutase fusion protein on UIO-66-NH2 for enhanced photocatalytic hydrogen peroxide production

Efficiently enhancing hydrogen peroxide (H 2 O 2 ) production via photocatalysis remains challenging. This study employed genetic engineering to express His-tagged superoxide dismutase (His-SOD), which was selectively anchored onto the coordinatively unsaturated metal sites of etched UIO-66-NH₂ (UIO-66-NH 2 etch ) through coordination-driven assembly. The synergistic effect between His-SOD and UIO-66-NH 2 etch significantly enhanced both the stability and substrate affinity of the enzyme, while simultaneously boosting the photocatalytic activity of the MOF. Compared to its free counterpart, the immobilized His-SOD exhibits a 62 % increase in catalytic efficiency and a more than threefold extension in thermal deactivation half-life. The fabricated UIO-66-NH 2 etch @His-SOD composite achieved an impressive H 2 O 2 production rate of 3890.37 μmol·g −1 ·h −1 , exceeding that of the pristine UIO-66-NH 2 by over 2.5 times within 1 h and maintaining a 1.7-fold enhancement after 4 h. Owing to SOD's inherent superior antioxidative capabilities, the composite material demonstrates exceptional recyclability, retaining 95 % of its initial catalytic activity after four consecutive cycles. This study achieves specific immobilization of functionalized fusion proteins onto photocatalysts, and represents the first introduction of SOD into photocatalytic H 2 O 2 synthesis. This advancement provides valuable insights for the future integration of biocatalysts and synthetic photocatalysts, opening new avenue for research on photo-enzyme coupled catalysis.