Selective functionalization of high-resolution Cu₂O nanopatterns via galvanic replacement for highly enhanced gas sensing performance

Recently, high-resolution patterned metal oxide semiconductors (MOS) have gained considerable attention for enhanced gas sensing performance due to their polycrystalline nature, ultrasmall grain size (~5 nm), patternable properties, and high surface-to-volume ratio. Herein, we significantly enhanced the sensing performance of that patterned MOS by galvanic replacement, which allows for selective functionalization on ultrathin Cu₂ O nanopatterns. Based on the reduction potential energy difference between the base channel material (Cu₂ O) and the decorated metal ion (Pt²⁺), Pt could be selectively and precisely decorated onto the desired area of the Cu₂ O nanochannel array. Overall, the Pt-decorated Cu₂ O exhibited 11-fold higher NO₂ (100 ppm) sensing sensitivity as compared to the non-decorated sensing channel, the while the channel device with excessive Pt doping showed complete loss of sensing properties.