Coordination-Driven Direct Conversion of Layered Metal Borides Into Borophene/MOF Heterostructures

Engineering robust two-dimensional material/metal-organic framework (MOF) heterostructures with well-defined interfaces remains challenging, largely because conventional routes depend on sequential etching, exfoliation, and self-assembly steps that are inefficient, reagent-consuming, and prone to damage the two-dimensional components. Exposure to oxygen and aqueous media during these processes often induces surface oxidation and nanosheet fragmentation, severely limiting the functional advantages of the resulting hybrids. Here, we develop a coordination-driven conversion strategy that enables the single-step construction of borophene (BP)/MOF heterostructures from layered metal borides. With formic acid serving as a catalytic coordination modulator, the metal layers are selectively reconstructed into MOF domains while the intrinsic boron network is simultaneously exfoliated, enabling a broadly applicable, atom-efficient transformation with a yield up to 95%. The representative BP/Al-PMOF heterostructure features a mutually reinforcing interface, where BP improves MOF conductivity and the MOF matrix protects BP from oxidation. This interfacial synergy enables exceptional room-temperature NO₂ sensing with a strong response and fast detection.