Enhanced formaldehyde detection based on Ni doping of SnO2 nanoparticles by one-step synthesis

In this work, SnO2 nanoparticles with Ni doping were synthesized via a facile one-step hydrothermal route. The addition of Ni to SnO2 lead to significant enhanced response to formaldehyde (HCHO). The Ni-doped SnO2 materials were used to fabricate HCHO gas sensors and the comprehensive HCHO-sensing properties under diverse working temperatures were tested and studied. With suitable Ni concentration, the SnO2 nanoparticles exhibited a 10 times sensing enhancement with high gas response, excellent selectivity and good stability. Furthermore, the limit of detection (LOD) was experimentally figured out to be as low as 120 ppb, which is much lower than the threshold exposure limit of HCHO proposed by American Conference of Governmental Industrial Hygienists. Importantly, the excellent performances of the as-fabricated gas-sensing devices make Ni-doped SnO2 a promising candidate for HCHO sensing applications. This synthesis strategy here can also give guidance for designing high-performance HCHO gas sensors.