Abstract: The invention provides a ceramic composite oxide of formula (I): (1?x)AaBbOy+xCcDdOz (I) wherein A, B, C and D are each independently selected from the group consisting of Li, Na, Mg, Al, P, K, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Sr, Y, Zr, Nb, Mo, Ru, In, Sn, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Er, Tm, Yb, Lu, Ta, W, Bi and mixtures thereof; x is 0.05 to 0.95; y and z are balanced by the charge of the cations; 0?a, b, c, d?1; and wherein said ceramic composite oxide has an average particle size diameter of 10 to 700 nm.

Abstract: A process for the preparation of a niobium compound of formula (I): D?Nb?E?O3-???(I) wherein D is an alkali metal (e.g. Li, Na, K, Rb, Cs and/or Fr), alkaline earth metal (such as Ba, Ca, Mg and/or Sr), La and/or Bi and may be present as a mixture of two or more metals; E is Ta, Sb and/or Fe and may be present as a mixture of two or more metals; ? is a positive number ? is a positive number ? is zero or a positive number ? is a number 0???0.5; and wherein the formula (I) has the perovskite or tungsten bronze structure; comprising spray pyrolising a solution, for example an aqueous solution, comprising metal (D) ions, Nb ions and if present, metal (E) ions.

Abstract: Proton conductivity has been shown in acceptor-doped rare earth orthoniobates and tantalates (LnNbO4 and LnTaO4) at high temperatures and in a humid atmosphere. The use of the materials as an electrolyte in a laboratory-scale fuel cell and water vapor sensor has been demonstrated. Results for Ca-doped LaNbO4 are given as examples.

Abstract: A process for the preparation of a niobium compound of formula (I): D?Nb?E?O3-???(I) wherein D is an alkali metal (e.g. Li, Na, K, Rb, Cs and/or Fr), alkaline earth metal (such as Ba, Ca, Mg and/or Sr), La and/or Bi and may be present as a mixture of two or more metals; E is Ta, Sb and/or Fe and may be present as a mixture of two or more metals; ? is a positive number ? is a positive number ? is zero or a positive number ? is a number 0???0.5; and wherein the formula (I) has the perovskite or tungsten bronze structure; comprising spray pyrolising a solution, for example an aqueous solution, comprising metal (D) ions, Nb ions and if present, metal (E) ions.

Abstract: Proton conductivity has been shown in acceptor-doped rare earth orthoniobates and tantalates (LnNbO4 and LnTaO4) at high temperatures and in a humid atmosphere. The use of the materials as an electrolyte in a laboratory-scale fuel cell and water vapour sensor has been demonstrated. Results for Ca-doped LaNbO4 are given as examples.