Synthesis of Porous Submicron Gd_0.1Ce_0.9O_1.95 Particles by Carbon Nanoparticle-Addition Ultrasonic Spray Pyrolysis (CNA-USP) and Nanoparticle Preparation by Ball Milling

Figures & data

FIG. 1. Concept of carbon nanoparticle-addition ultrasonic spray pyrolysis (CNA-USP).

FIG. 2. Apparatus for synthesizing SOFC electrolyte material particles using ultrasonic spray pyrolysis (CNA-USP).

TABLE 1 Specific surface areas S_w obtained from N₂ adsorption isotherms of Gd_0.1Ce_0.9O_1.95 particles before and after 24-h grinding; particles were synthesized at T_H = 1073 K, C_c = 0, and 16 g L⁻¹

Cc [g L^−1]	Grinding	Sw [m^2/g]
0	Before	6.31
16	Before	15.1
16	After	22.9

FIG. 3. SEM images of particles synthesized using CNA-USP method from aqueous solutions of Ce(NO₃)₃ 6H₂O and Gd(NO₃)₃ 6H₂O dissolved in stoichiometric ratios of Gd_0.1Ce_0.9O_1.95 at C_c = (a) 0, (b) 8, (c) 16, and (d) 24 g L⁻¹, at C_total = 0.02 mol L⁻¹, T_H = 1273 K, and t_r = 9.4 s.

TABLE 2 Geometric mean diameter D_pg and geometric standard deviation σ_g obtained from SEM images for Gd_0.1Ce_0.9O_1.95 particles shown in Figure 3; particles were synthesized at C_c = 0–24 g L⁻¹ and T_H = 1273 K

Cc [g L^−1]	Dpg [nm]	σg [-]
0	212	1.58
8	254	1.43
16	263	1.37
24	224	1.51

TABLE 3 Concentrations of Ce³⁺ and Gd³⁺, C_Ce3+ and C_Gd3+, and atomic ratios of Ce³⁺ : Gd³⁺ in precursor solutions to which carbon nanoparticles were added

Cc [g L^−1]	CCe3+ [mM]	CGd3+ [mM]	Atomic ratio of Ce^3+ : Gd^3+
0	21.9	2.49	0.90 : 0.10
8	18.5	2.09	0.90 : 0.10
16	15.8	1.71	0.90 : 0.10
24	13.6	1.38	0.91 : 0.09

TABLE 4 Average crystallite size D_cry obtained from XRD patterns of Gd_0.1Ce_0.9O_1.95 particles shown in Figure 4, geometric mean diameter D_pg and geometric standard deviation σ_g obtained from SEM images shown in Figure 5; particles were synthesized at T_H = 873–1473 K and C_c = 16 g L⁻¹

TH [K]	Dcry [nm]	Dpg [nm]	σg [-]
873	12.4	309	1.39
1073	31.8	271	1.44
1273	41.4	263	1.37
1473	48.3	210	1.53

FIG. 4. XRD patterns of particles synthesized using CNA-USP method from aqueous solutions of Ce(NO₃)₃ 6H₂O and Gd(NO₃)₃ 6H₂O dissolved in stoichiometric ratios of Gd_0.1Ce_0.9O_1.95 at T_H = (a) 873 K, (b) 1073 K, (c) 1273 K, and (d) 1473 K compared to (e) JCPDS data for Gd_0.1Ce_0.9O_1.95, at C_total = 0.02 mol L⁻¹, C_c = 16 g L⁻¹, and t_r = 9.4 s.

FIG. 5. SEM images of Gd_0.1Ce_0.9O_1.95 particles synthesized using CNA-USP method at T_H = (a) 873 K, (b) 1073 K, (c) 1273 K, and (d) 1473 K, at C_total = 0.02 mol L⁻¹, C_c = 16 g L⁻¹, and t_r = 9.4 s.

FIG. 6. TG data of (a) Gd_0.1Ce_0.9O_1.95 particles synthesized using CNA-USP method at T_H = 873 K, 1073 K, 1273 K, and 1473 K, at C_total = 0.02 mol L⁻¹, C_c = 16 g L⁻¹, and t_r = 9.4 s and (b) carbon nanoparticles added in the precursor solutions.

FIG. 7. (a) SEM images of Gd_0.1Ce_0.9O_1.95 particles synthesized using CNA-USP method at C_c = 16 g L⁻¹ and EDX images of (b) Gd, (c) Ce, and (d) O contained in them, at C_total = 0.02 mol L⁻¹, T_H = 1073 K, and t_r = 9.4 s.

FIG. 8. SEM images of Gd_0.1Ce_0.9O_1.95 particles (a) before and after (b) 0.5 h, (c) 1 h, (d) 5 h, and (e) 24 h of ball-mill grinding of particles synthesized using CNA-USP method at C_c = 16 g L⁻¹, C_total = 0.02 mol L⁻¹, T_H = 1073 K, and t_r = 9.4 s.

FIG. 9. Size distributions of Gd_0.1Ce_0.9O_1.95 particles measured by DLS before and after 0.5, 1, 5, and 24 h of ball-mill grinding of particles synthesized using CNA-USP method at C_c = 16 g L⁻¹, C_total = 0.02 mol L⁻¹, T_H = 1073 K, and t_r = 9.4 s.