Amorphous
metal–organic frameworks (aMOFs) are highly attractive
for electrocatalytic applications due to their exceptional conductivity
and abundant defect sites, but harsh preparation conditions of “top-down”
strategy have hindered their widespread use. Herein, the scalable
production of aMIL-68(In)-NH2 was successfully achieved
through a facile “bottom-up” strategy involving ligand
competition with 2-methylimidazole. Multiple in situ and ex situ characterizations reveal that aMIL-68(In)-NH2 evolutes into In/In2O3–x
as the genuine active sites during the CO2 electrocatalytic
reduction (CO2RR) process. Moreover, the retained amino
groups could enhance the CO2 adsorption. As expected, the
reconstructed catalyst demonstrates high formate Faradaic efficiency
values (>90%) over a wide potential range of 800 mV in a flow cell,
surpassing most top-ranking electrocatalysts. Density functional theory
calculations reveal that the abundant oxygen vacancies in aMIL-68(In)-NH2 induce more local charges around electroactive sites, thereby
promoting the formation of HCOO* intermediates. Furthermore, 16 g
of samples can be readily prepared in one batch and exhibit almost
identical CO2RR performances. This work offers a feasible
batch-scale strategy to design amorphous MOFs for the highly efficient
electrolytic CO2RR.