Mesoporous CeO2 nanobelts synthesized by a facile hydrothermal route via controlling cationic type and concentration of alkali

Mesoporous CeO2 nanobelts have been synthesized by a facile hydrothermal route via controlling cationic type and concentration of alkali without any surfactant or template. The key synthesis of CeO2 nanobelts is forming the beltlike precursors in the presence of enough NaOH (Na/Ce molar ratio ⩾16.3 at 120 °C) during hydrothermal process. The enough OH− ions induce the two steps of Cannizzaro disproportionation reaction to result in conversion of formate partly into carbonate, and Na+ ions with small ionic radius allow coexistence of carbonate and formate in structure and accordingly are favorable to anisotropic growth of beltlike precursors. The increased hydrothermal temperature can promote the formation of carbonates and the minimal required Na/Ce molar ratio is decreased from 16.3 at 120 °C to 10.8 at 140 °C. When Na+ is substituted by the same concentration of K+ or NH4+, the obtained precursor products are finally nanowires or irregular morphology. XRD measurement proves that the sodium ions do not enter the crystalline frame of CeO2 nanobelts and can be easily removed by simple washing with deionized water. After washing, CeO2 nanobelts with enlarged mesoporous pores show superior catalytic performance for CO oxidation compared with CeO2 nanoparticles prepared with traditional methods.

Mesoporous CeO2 nanobelts are synthesized via a facile hydrothermal route including formaldehyde solution. The synthetic key factor of CeO2 nanobelts is forming the beltlike precursors with the coexistence of carbonate and formate by controlling Na/Ce molar ratio and hydrothermal temperature. After simple washing with deionized water, the CeO2 nanobelts show better catalytic performance for CO oxidation than the CeO2 nanoparticles prepared by traditional methods.Figure optionsDownload as PowerPoint slideHighlights
► Mesoporous CeO2 nanobelts are prepared by a facile hydrothermal method.
► The synthetic key is forming beltlike precursors at enough high Na/Ce molar ratio.
► Synergy of OH− ions and Na+ ions induces production of CeO2 nanobelt precursors.
► CeO2 nanobelts show better catalytic performance than CeO2 nanoparticles.