Amino Groups Enable Dynamic Sn 2+ /Sn 4+ Redox Cycling in Metal–Organic Frameworks to Boost Dual-Channel H 2 O 2 Production via Piezoelectric-Photocatalysis

Metal–organic framework (MOF) materials exhibit significant potential for hydrogen peroxide production from aqueous solutions through piezoelectric-photocatalysis. However, the high recombination rates of photogenerated electrons (e – ) and holes (h + ) still pose a significant challenge. To address this issue, the NH 2 –SnMOF catalyst was designed. The incorporation of amino groups facilitates efficient electron transfer, thereby promoting the Sn 2+ /Sn 4+ dynamic conversion within the SnMOF and enabling a dual-channel H 2 O 2 production mechanism. Concurrently, the introduction of −NH 2 reduces the symmetry of the SnMOF, enhances the structural polarity, generates a built-in electric field, and promotes the separation of photogenerated e – and h + . Notably, the catalyst shows remarkable H 2 O 2 production in oxygen-saturated aqueous solution without requiring sacrificial agents. Under the influence of the piezoelectric effect, this resulted in a high H 2 O 2 production rate of 22.38 mM·g –1 ·h –1, demonstrating promising potential for wastewater treatment applications. The reaction process simultaneously involves 2e – ORR and 2e – WOR, effectively utilizing both e – and h + in the redox reactions. Theoretical calculations reveal that amino functionalization increases the adsorption energy of SnMOF, significantly lowers the Δ G value of *OOH, and promotes the activation of O 2 . Oxygen adsorption oxidizes Sn 2+ to Sn 4+, which is then reduced back to Sn 2+ under electron influence. The amino group donates additional electrons to the Sn site, facilitating cyclic Sn 2+ /Sn 4+ conversion. The synergistic mechanism between amino ligand functionalization and metal site valence state conversion (Sn 2+ /Sn 4+ ) significantly enhances the performance of piezo-photocatalytic H 2 O 2 production. This work provides a theoretical framework for advancing piezo-photocatalytic H 2 O 2 production and expanding their applications across diverse research fields.