Electrospun Nb-doped CeO2 nanofibers for humidity independent acetone sensing

Niobium Modification of CeO2 Tuning Electron Density of Nickel–Ceria Interfacial Sites for Enhanced CO2 Methanation

“…34-0394), respectively, are observed . Furthermore, the absence of a distinct Nb 2 O 5 peak in the XRD patterns indicates the successful formation of the Nb–Ce–O solid solution upon Nb addition, as supported by the results of EDX mapping. ,, Notably, no significant NiO peak is observed in the XRD patterns due to the low Ni loading and the uniform dispersion of NiO particles. , …”

“…21 The energy-dispersive X-ray spectroscopy (EDX) element mapping in Figure 1e reveals the distribution of Ce and Nb, indicating the successful doping of Nb into the CeO 2 lattice, resulting in a solid solution with a uniform distribution of elements. 40 Moreover, the nanosized NiO is uniformly distributed on NbCe without any aggregation, confirming the presence of abundant contact surfaces and robust interactions between NiO and the NbCe support. 41 On the other hand, the HRTEM image of Ni/Ce in Figure 1d indicates that the CeO 2 support results in the formation of large particles with an irregular distribution, and NiO aggregates heavily on the surface of the CeO 2 carrier.…”

“…The abundant contact interface between Ni and the NbCe support further promotes the hydrogenation reaction . The energy-dispersive X-ray spectroscopy (EDX) element mapping in Figure e reveals the distribution of Ce and Nb, indicating the successful doping of Nb into the CeO 2 lattice, resulting in a solid solution with a uniform distribution of elements . Moreover, the nanosized NiO is uniformly distributed on NbCe without any aggregation, confirming the presence of abundant contact surfaces and robust interactions between NiO and the NbCe support .…”

“…Notably, the oxygen vacancy ratio of Ni/10NbCe (38.5%) is lower than that of Ni/Ce (47.1%). This discovery implies that the doping of Nb 5+ hinders the formation of oxygen vacancies due to the substitution of Ce 4+ with an additional electron which satisfies the covalent bond coordination. ,,, The Raman spectra were further provided to verify the oxygen vacancy concentrations for different catalysts (Figure S3). The obtained spectra exhibited two distinct peaks at 460 and 590 cm –1 , corresponding to the F 2g octahedrally symmetrical vibration modes and the D stretching vibration resulting from the presence of oxygen vacancies, respectively.…”

“…11 Furthermore, the absence of a distinct Nb 2 O 5 peak in the XRD patterns indicates the successful formation of the Nb−Ce−O solid solution upon Nb addition, as supported by the results of EDX mapping. 40,42,43 Notably, no significant NiO peak is observed in the XRD patterns due to the low Ni loading and the uniform dispersion of NiO particles. 16,39 To gain insights into the reduction process of Ni species in the Ni/NbCe catalyst, hydrogen-programmed temperature reduction experiments (H 2 -TPR) were conducted on catalysts with different Nb doping levels, as shown in Figure 2b.…”