General synthesis of porous spinel gallate nanospheres for selective and quick detection of formaldehyde

Spinel metal oxides , prepared at high temperature, have shown excellent gas sensing properties among metal oxide sensing materials. Herein, a series of porous spinel gallate nanospheres, including CdGa 2 O 4 , NiGa 2 O 4 , CoGa 2 O 4 , CuGa 2 O 4 , ZnGa 2 O 4 , and MgGa 2 O 4 were prepared by solvothermal method and followed low temperature calcination . XRD , SEM, XPS and N 2 adsorption-desorption have been carried out to determine their structure, morphology, chemical state and surface area, respectively. These nanospheres are all composed of tiny nanoparticles , giving meso-porous characters. Furthermore, the sensor based on CdGa 2 O 4 exhibits excellent formaldehyde sensing performance, including good selectivity, short response time, and excellent stability at the low working temperature of 120 °C.