In Situ Growth of Cu2O-Coated Cu Aggregates on Wood and Bamboo for Efficient Mold Resistance

Wood and bamboo products with log-term carbon storage, less energy consumption, and CO2 emission face the challenge of fungal infection. Their antifungal property can be enhanced by Cu-based nanoparticles. Herein, Cu2O-coated Cu (Cu2O@Cu) aggregates were grown in situ on the surface of pine wood (PW), beech wood (BW), oak wood (OW), and bamboo via vacuum impregnation. Morphology, crystalline structure, elemental ratio, and chemical state of Cu2O@Cu and Cu2O@Cu-loaded specimens were characterized. Uniformly distributed agglomerates composed of Cu2O@Cu exhibited an average size of 2 μm (Cu2O@Cu-loaded PW and Cu2O@Cu-loaded BW) and several hundred nanometers (Cu2O@Cu-loaded OW and Cu2O@Cu-loaded bamboo) on the surfaces. A strong mold resistance for Aspergillus niger was achieved after cultivating Cu2O@Cu-loaded specimens for 28 days. Infection values were grade 0 for Cu2O@Cu-loaded PW and grade 1 for Cu2O@Cu-loaded BW, Cu2O@Cu-loaded OW, and Cu2O@Cu-loaded bamboo (p < 0.05), which were significantly better than those of pristine specimens (grade 2 for PW and grade 4 for BW, OW and bamboo). A low leaching rate of 5.23–7.81% with three repetitions presented a monotonically positive relation with the loading atomic content of Cu (12.6–27.1 at. %), demonstrating an excellent stability of Cu2O@Cu-loaded specimens. This study highlighted the potential of Cu-based preservatives in the field of wood and bamboo preservation.