Unveiling the influence of alkaline modifiers in CuO synthesis on its photocatalytic activity for CO2 reduction

Abstract

The urgent quest for sustainable solutions to mitigate CO2 emissions underscores the critical role of advanced photocatalytic technologies. This investigation centers on developing CuO photocatalysts through a well-established chemical precipitation method. In this context, our methodological innovation lies in varying the alkaline composition using NaOH, KOH, NH4OH, and the novel incorporation of monoethanolamine (MEA) to explore their influence on the catalyst's effectiveness. The characterization revealed that all CuO samples shared a similar monoclinic structure and crystallite sizes despite marked differences in particle morphology and dispersion. MEA's introduction significantly altered the surface chemistry of CuO, introducing nitrogen-containing functional groups that enhanced photocatalytic CO2 reduction, particularly boosting methane production. Moreover, our study reveals a synergistic combination of MEA and KOH (MEA/KOH) in the catalyst synthesis process, surpassing the performance of single-alkali modifications. It is attributed to the rapid particle nucleation induced by KOH and the surface functionalization provided by MEA, cooperating to optimize the CO2 photoreduction activity. Our study provides valuable insights into synthesizing photocatalysts tailored for enhanced CO2 conversion, advancing sustainable technologies in the fight against climate change.