Structure, microstructure and surface of Nd 3+ -doped mesoporous anatase-phase TiO 2

We prepared nanocrystalline mesoporous anatase-phase TiO2 doped in the range from 0.0 to 1.0 at.% of Nd3+ by the reverse microemulsion method (RMM). The analysis of electron microscopy of the nanocrystal revealed a truncated-tetragonal bipyramidal shape and agglomerates of spheroidal nanoparticles with inter-particle porosity. The inductively coupled plasma (ICP) technique corroborated the doping concentrations. The analysis of structural parameters by the Rietveld refinement technique indicated the variation of Ti–O(1) and Ti–O(2) bond lengths, suggesting the Nd3+ insertion in the lattice. The microstructural analysis by the Williamson–Hall plot (WH) and whole powder pattern fitting (WPPF) revealed that the doping addition has a slight inhibition effect on the crystal size (6–8 nm) with a minor strain increment. The surface analysis from N2 adsorption/desorption isotherms showed that the incorporation of the dopant in low amounts improved the mesoporous structure stability, increased the diameter of opening pores, and changed the pore structure network. The XPS analysis of the chemical states on the surface suggests that the Nd3+ presence changed the Ti 2p region and the presence of the two chemical states of oxygen (OI and OII).