Design of Ni-MOF@biochar heterostructures via ligand-induced distortion for highly selective N2H4 sensing

This study presents a N 2 H 4 sensing material based on a Ni-MOF@BC heterostructure fabricated via a solvothermal route. The composite shows room-temperature sensing properties with a broad linear detection range and low detection limit. The performance mechanism is governed by a synergistic effect that combines the conductive network of BC for accelerated charge transfer, the catalytic activity of Ni-MOF, a built-in electric field for efficient charge separation, and hierarchically porous channels for enhanced gas permeation. A key structural feature, ligand competition-induced lattice distortion forming η -NiO 6 octahedra, is identified as crucial for the high selectivity toward N 2 H 4 . This unique distortion optimizes the adsorption energy and facilitates orbital hybridization between the sensor and N 2 H 4 molecules, leading to a stronger and more specific interaction. Furthermore, the material features intelligent humidity-responsive mode-switching, enabling dual-purpose detection across varying ambient conditions. By utilizing Lyocell-derived carbon, this work exemplifies a sustainable design strategy for multifunctional sensing materials, offering a promising route toward low-power, adaptive gas monitoring technologies.