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 NH2–SnMOF catalyst was designed. The incorporation of amino groups facilitates efficient electron transfer, thereby promoting the Sn2+/Sn4+ dynamic conversion within the SnMOF and enabling a dual-channel H2O2 production mechanism. Concurrently, the introduction of −NH2 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 H2O2 production in oxygen-saturated aqueous solution without requiring sacrificial agents. Under the influence of the piezoelectric effect, this resulted in a high H2O2 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 ΔG value of *OOH, and promotes the activation of O2. Oxygen adsorption oxidizes Sn2+ to Sn4+, which is then reduced back to Sn2+ under electron influence. The amino group donates additional electrons to the Sn site, facilitating cyclic Sn2+/Sn4+ conversion. The synergistic mechanism between amino ligand functionalization and metal site valence state conversion (Sn2+/Sn4+) significantly enhances the performance of piezo-photocatalytic H2O2 production. This work provides a theoretical framework for advancing piezo-photocatalytic H2O2 production and expanding their applications across diverse research fields.