Selective Functionalization of High-Resolution Cu2O Nanopatterns via Galvanic Replacement for Highly Enhanced Gas Sensing Performance

Abstract

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 (similar to 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 Cu2O nanopatterns. Based on the reduction potential energy difference between the base channel material (Cu2O) and the decorated metal ion (pt(2+)), Pt could be selectively and precisely decorated onto the desired area of the Cu2O nanochannel array. Overall, the Pt-decorated Cu2O 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.