Hollow Carbon Nanospheres/UiO-66 Composites: Fabrication and VOCs Adsorption Performance

doi:10.15541/jim20250445

Abstract

Abstract:

Volatile organic compounds (VOCs) significantly threaten both environmental sustainability and public health. However, it remains challenging to combine high capacity and stability in most existing adsorbents. In this work, hollow carbon nanospheres (HCNS) were synthesized under alkaline conditions using tetrapropyl orthosilicate as the silicon source, followed by modulation of their surface hydroxyl content through variations in alkali concentration or temperature to yield a series of HCNS-x. These HCNS-x were then composited with UiO-66, which possesses a high specific surface area and excellent thermal stability, to prepare HCNS-x/UiO-66 composites. Their surface properties and structures were investigated through various characterization techniques. The results indicated that HCNS-2, activated with 3 mol/L NaOH at 60 ℃, exhibited the highest surface hydroxyl content. Furthermore, its corresponding composite, HCNS-2/UiO-66, demonstrated the most optimal pore structure parameters (a specific surface area as high as 3694 m²·g^-1, a total pore volume of 2.53 cm³·g^-1, and an average pore size of 6.9 nm). Static toluene adsorption tests revealed that the toluene adsorption capacity of HCNS-2/UiO-66 was 2.305 g·g^-1, which was 10.5 times that of pure UiO-66 (0.220 g·g^-1) and 1.6 times that of pristine HCNS (1.436 g·g^-1). Dynamic toluene adsorption breakthrough curve analysis confirmed that HCNS-2/UiO-66 possessed the most excellent toluene adsorption performance with an equilibrium adsorption capacity of 2.140 g·g^-1, which was attributed to its large specific surface area and optimized pore structure. Additionally, cycling tests demonstrated that HCNS-2/UiO-66 maintained stable performance over multiple dynamic adsorption-desorption cycles, demonstrating that its saturated adsorption capacity consistently remained around 2.15 g·g^-1. This study constructed a VOCs adsorbent with high adsorption capacity and stability by modifying the HCNS surface to optimize its interfacial integration with UiO-66.

Key words: hollow carbon nanosphere, composite, volatile organic compound, adsorption, surface modification

CLC Number:

X511

WANG Han, QING Jiang, HUANG Honghua, WANG Hongning, YAO Chao, CHEN Ruoyu. Hollow Carbon Nanospheres/UiO-66 Composites: Fabrication and VOCs Adsorption Performance[J]. Journal of Inorganic Materials, 2026, 41(9): 1285-1293.

Figures/Tables 21

Fig. 1 XRD patterns of the samples (a) HCNS and HCNS-x samples; (b) UiO-66 and HCNS-x/UiO-66 samples

Fig. 2 FT-IR spectra of the samples (a) HCNS and HCNS-x samples; (b) UiO-66 and HCNS-x/UiO-66 samples

Fig. 3 Static water adsorption capacities of samples under different activation conditions

Fig. 4 SEM images of the samples (a) UIO-66; (b) HCNS; (c) HCNS-1; (d) HCNS-1/UiO-66; (e) HCNS-2; (f) HCNS-2/UiO-66; (g) HCNS-3; (h) HCNS-3/UiO-66

Fig. 5 TEM images of the samples (a) HCNS; (b) UiO-66; (c) HCNS-1; (d) HCNS-1/UiO-66; (e) HCNS-2; (f) HCNS-2/UiO-66; (g) HCNS-3; (h) HCNS-3/UiO-66

Fig. 6 N2 adsorption-desorption isotherms (a, b) and pore size distribution curves (c, d) of the samples

Fig. 7 Static toluene adsorption capacities of the samples (a) UiO-66, HCNS and HCNS-x samples; (b) HCNS+UiO-66, HCNS/UiO-66 and HCNS-x/UiO-66 samples

Fig. 8 Dynamic toluene adsorption breakthrough (fitting) curves of different samples

Fig. 9 Dynamic toluene adsorption breakthrough curves of HCNS-2/UiO-66 at different temperatures

Fig. S1 Linear relationship between static water adsorption capacity and density of surface hydroxyl

Fig. S2 Static water desorption efficiency of samples under different activation conditions

Fig. S3 SEM image (a) and TEM image (b) of HCNS/UiO-66

Fig. S4 TGA curves of the samples

Fig. S5 Static adsorption capacities (a) and desorption efficiencies (b) of the samples

Fig. S6 Static toluene desorption efficiencies of the samples

Table S1 Static water adsorption capacities, desorption efficiencies and density of surface hydroxy of different samples

Sample	Adsorption capacity/(g·g^-1)	Desorption efficiency/%	D/(×10²⁰, g^-1)
HCNS	0.8850	99.62	2.85
HCNS-1	0.9615	99.64	3.03
HCNS-2	1.1020	99.20	3.54
HCNS-3	0.9056	99.44	2.91

Table S2 Pore structure parameters of the samples

Sample	S_BET/ (m²·g^-1)	Pore volume, V_t/(cm³·g^-1)	Micropore volume, V_m/(cm³·g^-1)	Pore diameter/nm
HCNS	968	1.25	0.10	5.2
HCNS-1	1069	1.60	0.12	6.0
HCNS-2	1514	2.23	0.62	6.0
HCNS-3	1055	1.13	0.18	5.9
UiO-66	236	0.16	0.10	2.7
HCNS-1/UiO-66	1504	2.47	0.19	6.6
HCNS-2/UiO-66	3694	2.53	0.44	6.9
HCNS-2/UiO-66	1470	2.41	0.14	6.6

Table S3 Dynamic toluene adsorption parameters of different samples

Sample	t_b/min	t_e/min	q_e/(g·g^-1)	Desorption efficiency/%
UiO-66	16	68	0.198	99.5
HCNS-1/UiO-66	68	148	1.586	99.6
HCNS-2/UiO-66-1st	90	210	2.140	98.7
HCNS-2/UiO-66-2nd	90	214	2.150	99.3
HCNS-2/UiO-66-3rd	98	206	2.200	99.7
HCNS-2/UiO-66-4th	94	214	2.230	99.6
HCNS-2/UiO-66-5th	90	212	2.130	99.3
HCNS-3/UiO-66	60	128	1.382	98.9

Table S4 Dynamic toluene adsorption fitting parameters of different samples

Sample	τ₀/min	k′/min^-1	R²
UiO-66	30.9	0.337	0.997
HCNS-1/UiO-66	55.3	0.224	0.997
HCNS-2/UiO-66-1st	122	0.087	0.998
HCNS-2/UiO-66-2nd	118	0.087	0.998
HCNS-2/UiO-66-3rd	114	0.087	0.998
HCNS-2/UiO-66-4th	110	0.092	0.995
HCNS-2/UiO-66-5th	112	0.094	0.995
HCNS-3/UiO-66	77.1	0.194	0.997

Table S5 Performance comparison of different categories of VOCs adsorbents

Category	Sample	S_BET/(m²·g^-1)	q_e/(g·g^-1)	Ref.
Porous carbon materials	AC	1654	0.48	[40]
Porous carbon materials	HCNS	968	1.436	This work
Zeolites	ZSM-5	418	0.12	[41]
MOFs	MIL-101	2907	0.55	[42]
MOFs	UiO-66	236	0.220	This work
Composite materials	C/Si	431	0.11	[43]
Composite materials	HCNS-2/UiO-66	3694	2.140	This work

Table S6 Dynamic toluene adsorption fitting parameters of the samples at different temperatures

Sample	t_b/min	t_e/min	q_e/(g·g^-1)	Desorption efficiency/%
HCNS-2/UiO-66-25 ℃	90	210	2.140	98.7
HCNS-2/UiO-66-60 ℃	40	120	1.304	99.2
HCNS-2/UiO-66-80 ℃	20	64	0.639	99.4

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