CdS/NH2-UiO-66 hybrid membrane reactors for the efficient photocatalytic conversion of CO2

Abstract

Strategies for effectively enhancing the photoreduction of CO₂ have been studied for several decades. Compared to powder catalysts, membrane catalysts can overcome the disadvantages of light scattering, easy aggregation, and difficult recovery. In our study, a CdS/NH₂-UiO-66 hybrid membrane was prepared using chitosan as the carrier. It is worth pointing out that chitosan was selected as the membrane matrix due to its abundant amine and carboxyl groups, which are favorable for the adsorption of CO₂. The X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images illustrate that CdS and NH₂-UiO-66 were uniformly distributed in the membrane. The photocatalytic activity of the CdS/NH₂-UiO-66 hybrid membrane was explored under mild environmental conditions. The photocatalytic results show that the hybrid membrane has higher photocatalytic activity compared with the single CdS or NH₂-UiO-66 membrane. Moreover, the activity and selectivity (99%) of the CdS/NH₂-UiO-66 membrane catalyst are higher than those of the CdS/NH₂-UiO-66/chitosan mixed powder catalyst (95%). By performing fluorescence spectroscopy (PL) and electrochemical impedance spectroscopy (EIS) and measuring the photocurrent, it is found that the electron transfer of hybrid membranes was accelerated and the photogenerated electron–hole pairs were well separated compared to powder catalysts. Moreover, the CdS/NH₂-UiO-66 hybrid membrane has good stability.