Transition metal elements-doped SnO(2) for ultrasensitive and rapid ppb-level formaldehyde sensing

Pristine SnO(2), Fe-doped SnO(2) and Ni-doped SnO(2) were synthesized using facile hydrothermal method. Analysis based on XRD, TEM and UV–Vis DRS measurements demonstrated the successful insertion of Fe and Ni dopants into SnO(2) crystal. Formaldehyde-detection measurements revealed that transition metal-doped SnO(2) exhibited improved formaldehyde-sensing properties compared with that of pristine SnO(2). When the amount of incorporated dopant (Fe or Ni) was 4 at.%, the most effective enhancement on sensing performance of SnO(2) was obtained. At 160 °C, the 4 at.% Fe–SnO(2) and 4 at.% Ni–SnO(2) exhibited higher response values of 7.52 and 4.37 with exposure to low-concentration formaldehyde, respectively, which were 2.4 and 1.4 times higher than that of pristine SnO(2). The change of electronic structure and crystal structure as well as catalytic effect of transition metals are chiefly responsible for the enhanced sensing properties.