Synergistic effects of α-Fe₂O₃ nanoparticles and Fe-doping on gas-sensing performance of NiO nanowires and interface mechanism

Abstract

High surface area nickel oxide nanowires (NiO NWs), Fe-doped NiO NWs and α-Fe2O3/Fe-doped NiO NWs were synthesized with nanocasting pathway, and then the morphology, microstructure and components of all samples were characterized with XRD, TEM, EDS, UV–vis spectra and nitrogen adsorption–desorption isotherms. Owing to the uniform mesoporous template, all samples with the same diameter exhibit the similar mesoporous-structures. The loaded α-Fe2O3 nanoparticles should exist in mesoporous channels between Fe-doped NiO NWs to form heterogeneous contact at the interface of n-type α-Fe2O3 nanoparticles and p-type NiO NWs. The gas-sensing results indicate that Fe-dopant and α-Fe2O3-loading both improve the gas-sensing performance of NiO NWs sensors. α-Fe2O3/Fe-doped NiO NWs sensors presented the highest response to 100 ppm ethanol gas (55.264) compared with Fe-doped NiO NWs (24.617) and NiO NWs sensors (3.189). The donor Fe-dopant increases the ground state resistance and the absorbed oxygen content in air. α-Fe2O3 nanoparticles in electron depletion region result in the increasing resistance in ethanol gas and decreasing resistance in air. In this way, α-Fe2O3/Fe-doped NiO NWs sensor presents the excellent gas-sensing performance due to the formation of heterogeneous contact at the interface.

Enhanced xylene sensing performance of hierarchical flower-like Co3O4 via In doping

“…[29] Therefore, E g can be calcu-lated by extrapolating the peak linear portion of the (αhν) 2hν curve to the energy axis. [30] As shown in Fig. 4(b), E g of Co 3 O 4 , In@Co 3 O 4 -1, In@Co 3 O 4 -4, and In@Co 3 O 4 -7 are 3.47 eV, 3.39 eV, 3.16 eV, and 2.97 eV, respectively.…”

NiO-Based Gas Sensors for Ethanol Detection: Recent Progress

“…Furthermore, doping induces lattice distortion and introduces more oxygen vacancy defects. When detecting ethanol, ethanol molecules are easily trapped by oxygen vacancy defects, allowing more target molecules to react with NiO, resulting in a larger gas response [85][86][87]. Shailja et al [88] introduced Ga 3+ into NiO.…”