Copper oxide Nanoparticles (CuO) were synthesized as described by Zhu et al. with slight modifications . A mixture was prepared by combining 40.1 mL of water, 3.2 mL of copper acetate monohydrate (0.25 M, aq.) and 66.7 µL of glacial acetic acid and heating to a temperature setpoint of 95 °C for the heating block (resulting in an internal temperature of ca. 80 °C) under stirring at 700 rpm. After temperature stabilization for 5 mins, 2.67 mL of NaOH (1M, aq.) were added at a rate of 1 mL/min, while the heating and stirring was continued for 20 min. The particles were then cooled down, purified by 2 cycles of centrifugation (14k rcf, 10 min, 25°C) and ultrasonic redispersion (20 s) in water (20 mL).