Synergistic effect of lightning rod and piezo-photocatalysis in sea urchin-shape Zn-MOF-74@g-C3N4 3 N 4 step-scheme heterojunction for H2O2 2 O 2 production under visible light irradiation

Piezo-photocatalytic H2O2 2 O 2 production was an emerging environmental technology that could convert solar energy into green chemicals, garnering significant attention. This study combined lightning rod effect and piezophotocatalysis to achieve H2O2 2 O 2 production through an indirect two-electron oxygen reduction reaction pathway. A composite catalyst, sea urchin-shaped Zn-MOF-74@g-C3N4, 3 N 4 , had a surface of spherical Zn-MOF-74 made up of graphite phase carbon nitride nanoneedles with high curvature tips. These tips could induce a "lightning rod effect" property, accelerating charge transfer and separation by guiding electron migration along the sharp tip direction. The piezo-photocatalytic process, along with the construction of step-scheme heterojunction, generated a dual electric field, significantly enhancing the separation and migration rate of photo- generated carriers. As a result, the prepared Zn-MOF-74@g-C3N4 3 N 4 demonstrated a higher H2O2 2 O 2 production rate under the synergistic effect of lightning rod and piezo-photocatalysis. Free radical trapping experiments were conducted on various active species to uncover the mechanism behind the piezo-photocatalytic dual electric field coupling to produce H2O2. 2 O 2 .