A hierarchical graphitic carbon nitride supported by metal–organic framework and copper nanocomposite as a novel bifunctional catalyst with long-term stability for enhanced carbon dioxide photoreduction under solar light irradiation

Abstract

Metal–organic frameworks are considered as prospering photocatalysts, which can potentially generate high CO2 removal capacity arising from their large pores and great superficial area. The present study’s aim is the utilization of g-C3N4@Cu/ ZIF-8 nanocomposite to eliminate its structural defects by applying two strategies viz. doping Cu and core-shelling ZIF-8 on g-C3N4. The solvothermal method was used to prepare g-C3N4@Cu/ZIF-8 nanocomposite. Chemical and physical characterizations of the nanocomposite were identified by the different analyses. Photoreduction of CO2 was implemented in a 200-mL domestic Pyrex batch reactor under environment temperature as well as atmospheric pressure and sunlight was used as the light source. The results indicated that the CH3OH production performance in g-C3N4@Cu/ZIF8 (1%) nanocomposite was about three times higher than ZIF-8, which emerged via an increase in the surface area, decrease in electron–hole recombination rate, increase in conductivity, and decrease in bandgap invoking CO2 adsorption capacity increase. The amount of CO2 absorption in samples was 0.039 (ZIF-8), 0.043 (Cu/ZIF-8), 0.051 (g-C3N4), and 0.12 (g-C3N4@Cu/ZIF-8 (1%)) mmolg−1 respectively. In addition, reusability and stability testing showed that after 5 reuses of the prepared nanocomposite, the degradation efficiency of CO2 photoreduction decreased from 82.1 to 71.8%.