Enhanced p-p orbital coupling for efficient CO₂-to-formate conversion via counterion-induced amorphization strategy...

Electrocatalytic reduction of CO₂ to high-value chemicals and fuels, such as formate, offers a promising route to achieve carbon neutrality and climate change mitigation. In this work, we report a counterion-induced amorphization strategy applied to anionic indium metal-organic frameworks (In-MOFs) aimed at strengthening the binding of desired intermediates for efficient CO₂ electroreduction. In-TDC containing the small counterion Me₂NH₂⁺ undergoes facile cation exchange, triggering framework reconstruction into an amorphous phase (A-In(OH)_x(CO₃)_y). The A-In(OH)_x(CO₃)_y catalyst achieves a FE_formate of 97.2% at -1.4 V vs. RHE and maintains ∼90% selectivity for 36 h, far surpassing the other anionic crystalline analogue In-TEA with the bulky counterion TEA⁺ as a structural "anchor" for resisting collapse. Experimental and theoretical studies indicated that the better performance of A-In(OH)_x(CO₃)_y results from the strong orbital coupling between In p and O p of *OCHO, which not only lowers the free energy barrier for the conversion of *CO₂ to *OCHO but also enhances the *OCHO binding. This work highlights counterion exchangeability as a powerful tool to unlock p-orbital activity for efficient CO₂ electroreduction.