Facile synthesis of CuO nanocages and gas sensing performance towards gasoline

Facile synthesis of uniform cubic cuprous oxide (CuO) nanocages has been realized via an acidic etching method without any surfactant at 35°C. The edge length of the CuO nanocages was 80-90 nm, and the thickness of the walls was about 5 nm. Moreover, the wall thickness of these nanocages could be adjusted by changing the reaction temperature. The formation mechanism of the CuO nanocages was investigated. Ascorbic acid played an important role in this experiment. Owing to its reducing action, Cu(OH) was first reduced to solid CuO nanocubes in an aqueous solution. Almost immediately these nanocubes were etched into hollow ones through the acidic etching effect. Eventually, CuO nanocages which had thinner walls and more complete structures than those previously mentioned were produced in the presence of hydrazine hydrate (NH·HO). The as-prepared CuO nanocages have superior gas sensing performance toward gasoline comparing with the solid CuO nanocubes.