Construction of HKUST-1@Cu nanofibers with thermal conductive adsorption sites for synchronous enhancement of toluene adsorption and desorption efficiency

Abstract

A major challenge in utilizing metal–organic frameworks (MOFs) for volatile organic compound (VOC) capture was their inclination for strong adsorption, which consequently impeded desorption and elevated energy demand. To overcome this challenge, the construction of HKUST-1@Cu nanofibers (HK@Cu-NF) with thermal conductive adsorption sites was proposed to synchronous enhance toluene adsorption and desorption efficiency for VOCs capture. In this work, Cu-based HKUST-1 was designed to grow on Cu nanofibers, and formed uniform coverage MOF layer with tight connection via homologous Cu self-transformation growth strategy. The synthesized composite was proved to maintain high surface area (1473 m2/g) and generate abundant unsaturated Cu sites on its nanointerface based from the thermally conductive Cu nanofibers. This unique connection structure endowed these adsorption sites with high affinity towards toluene and high thermal conductivity as well, and finally formed thermal conductive adsorption sites. As a result, HK@Cu-NF composite (80 % loading of HKUST-1) exhibited 1.9 times higher of toluene adsorption capacity at P/P0 = 0.002 and >3 times higher of thermal diffusivity than pure HKUST-1. Furthermore, it achieved enhancement in both adsorption and desorption efficiency for toluene, which reached 4.8 and 6.9 times of pure HKUST-1. Therefore, construction of thermal conductive adsorption sites successfully improved the adsorption efficiency and regeneration efficiency for VOCs capture, and realized the low energy VOCs desorption process.