in nitrogen; toluene

catalyst: CH3COOH in further solvent(s) Sr(CH3COO)2, BiONO3, and Ta(OC2H5)5 in a mole ratio of 1:2:2 dissolved in 2-methoxyethanol at 80°C; pH adjusted to 3.5; transparent gel formed; dried at 100°C; calcined at 500°C for 1 h; XRD, TEM, IR;

catalyst: CH3COOH in further solvent(s) Sr(CH3COO)2, BiONO3, and Ta(OC2H5)5 in a mole ratio of 1:2:2 dissolved in 2-methoxyethanol at 80°C; pH adjusted to 3.5; transparent gel formed; dried at 100°C; calcined at 500°C for 1 h; XRD, TEM, IR;