One-step synthesis of Cu2O@carbon nanocapsules composites using sodium alginate as template and characterization of their visible light photocatalytic properties

Abstract A One step-synthesis method was developed to fabricate composite photocatalysts from cuprous oxide and carbon nanocapsules (Cu 2 O/CNC), using sodium alginate as a template. Carbon nanocapsules and nanosheets were self-generated by calcination in the presence of Cu 2+ species. And Cu 2 O particles with a diameter of 20–50 nm were distributed in the carbon nanocapsules or on the surface of the carbon nanosheets. The carbon nanomaterials provide a large surface area, which makes it easier for Cu 2 O to immobilize dye molecules through hydrogen bonding. Batch adsorption and degradation experiments were carried out using catalysts synthesized under different conditions, including sodium alginate fraction, crosslinker concentration, and precipitant concentration. The results showed that the Cu 2 O/CNC composite catalysts exhibited excellent photodegradation performance under visible light, removing 90% of methyl red in 120 min. The removal efficiency and photodegradation rate were affected significantly by a) the specific area of the catalysts; b) the morphologies of Cu 2 O and carbon nanomaterials; c) the synergy between Cu 2 O and carbon nanomaterials. A detailed mechanism for the enhancement of photocatalytic activity towards degradation of methyl red is proposed.