Well‐Defined Cu₂O/Cu₃(BTC)₂ Sponge Architecture as Efficient Phenolics Scavenger: Synchronous Etching and Reduction of MOFs in confined‐pH NH₃⋅H₂O

Abstract Fabrication of low‐dimensional nano‐MOFs as well as nanoparticles/metal‐organic frameworks (MOFs) hybrids has sparked new scientific interests but remains a challenging task. Taking Cu₃(BTC)₂ as a proof of concept, it is demonstrated thats NH₃⋅H₂O solution of a confined pH value can readily shape the bulk Cu₃(BTC)₂ into nanoscale Cu₃(BTC)₂, beyond the need to control the crystal growth kinetics of MOFs. Adjusting the pH of NH₃⋅H₂O within a much small range (10–11) allows fine tuning over the size and shape of nanoscale Cu₃(BTC)₂. Particularly at pH = 11, NH₃⋅H₂O exhibits weak reducibility that triggers a reduction of part of Cu₃(BTC)₂ into Cu₂O, while shaping the other into Cu₃(BTC)₂ nanowires. Benefiting from the coincidence of reduction and etching effects, the newly generated Cu₂O dots can in situ anchor onto adjacent Cu₃(BTC)₂ nanowires at highly dispersive state, forming a well‐defined sponge‐like architecture built of Cu₂O dots and nano‐Cu₃(BTC)₂. The CuO_x derived from annealing of the Cu₂O dots/nano‐Cu₃(BTC)₂ hybrid preserves the sophisticated sponge architecture and high porosity, and exhibits promising applications in phenol scavenging, with efficiency outperforming its counterparts and many other Cu‐based catalysts reported in literature. It is anticipated that the findings here pave the way for the rational design of intricate nano‐MOFs in a more efficient way.