Optimised Synthesis of Rhombic dodecahedral Cu2O Nanoparticles: A Pathway to Superior Morphological Control

Abstract

Cuprous oxide (Cu₂O) nanoparticles hold significant promise for photocatalytic applications due to their narrow bandgap and high surface reactivity. This study focuses on the synthesis of rhombic dodecahedral Cu₂O (RD-Cu₂O) nanoparticles, totally enclosed by {110} facets, known to exhibit superior photocatalytic performance over the other low-index crystallographic facets. The precise control over the synthesis conditions can significantly enhance the exposure of this highly active face and therefore improve the catalytic performance of Cu₂O nanoparticles, making them superior for applications in pollutant degradation, organic reactions, and artificial photosynthesis. We systematically optimised the synthesis parameters, including reactants concentration, pH and other reaction conditions, to achieve a significant scale up of well-defined RD- Cu₂O nanoparticles production, strictly necessary for the use of this photocatalyst on a larger scale. The optimised and scaled up synthesis require 2.0 mmol of CuCl₂, 6.0 mmol of Sodium dodecyl sulphate (SDS), 9.6 mmol of NH₂OH ⋅ HCl and 7.0 mmol of NaOH added in this order to 400 ml of water at 25 °C. The optimised nanoparticles demonstrated a narrow size distribution and a high degree of crystallographic control. Characterisation techniques such as FESEM, XRD, EPR, UV-Vis spectroscopy, and XPS confirmed the improved morphological and structural properties of the synthesised RD-Cu₂O nanoparticles.