Tuning Oxygen Vacancies in δ-MnO2 by the In-Situ Modification of CaSn(OH)6 to Enhance Formaldehyde Catalytic Oxidation Activity at Room Temperature

Ruimei Fang; Quanlin Li; Guoxin Lv; Xiaoai Luo; Hao Ma; Haibao Huang

doi:10.53941/dn.2026.100004

Abstract

The efficient elimination of indoor formaldehyde (HCHO) at room temperature continues to be a challenge, particularly under moisture-deficient conditions where conventional catalysts often suffer from rapid deactivation. In this work, a mild in-situ modification strategy using CaSn(OH)₆ was developed to engineer oxygen vacancies within layered δ-MnO₂, significantly enhancing its catalytic robustness. The optimized catalyst (MCS-1) exhibited superior HCHO oxidation performance, maintaining a high removal efficiency of 95% for over 260 min. Crucially, the catalyst demonstrated exceptional tolerance to low-humidity environments (RH = 20%), retaining >95% efficiency for 180 min, substantially outperforming pristine δ-MnO₂. The characterization results of XPS and EPR reveal that CaSn(OH)₆ incorporation facilitates the formation of oxygen vacancies. The shift of the lattice oxygen desorption peak to a lower temperature in the TPD results indicates that the modification by CaSn(OH)₆ enhances the mobility of lattice oxygen. This synergistic effect promotes the activation of molecular oxygen and facilitates the rapid desorption of carbonate intermediates, thereby preventing active site blocking. This work provides a promising defect-engineering strategy for designing high-performance manganese-based catalysts tailored for harsh indoor environments.

References

1.
Ait Benhamou, A.; Abid, L.; Calvez, I.; et al. Advances in lignin chemistry, bonding performance, and formaldehyde emission reduction in lignin-based urea-formaldehyde adhesives: A Review. ChemSusChem 2025, 18, e202500491.
2.
Liu, J.; Wang, Y.; Ji, W. Formaldehyde pollution characteristics and health risk assessment of workers during indoor renovation. Build. Environ. 2026, 287, 113853.
3.
Chen, L.; Yang, N.; Li, K.; et al. Dynamic evolution of Mn–O site and ROS formation in room-temperature formaldehyde oxidation over phase-dependent MnO₂. Environ. Sci. Technol. 2025, 59, 24092–24102.
4.
Khoshakhlagh, A.H.; Mohammadzadeh, M.; Sicard, P.; et al. Human exposure to formaldehyde and health risk assessment: A 46-year systematic literature review. Environ. Geochem. Health 2024, 46, 206.
5.
Shan, C.; Wang, Y.; Li, J.; et al. Recent advances of VOCs catalytic oxidation over spinel oxides: Catalyst design and reaction mechanism. Environ. Sci. Technol. 2023, 57, 9495–9514.
6.
Zhao, J.; Xi, W.; Tu, C.; et al. Catalytic oxidation of chlorinated VOCs over Ru/Ti_xSn_1-x catalysts. Appl. Catal. B. Environ. 2020, 263, 118237.
7.
Chen, R.; Sun, Z.; Hardacre, C.; et al. The current status of research on the catalytic oxidation of formaldehyde. Catal. Rev. 2024, 66, 1028–1083.
8.
Liu, X.; Lu, T.; Jiao, X.; et al. Formaldehyde ambient-temperature decomposition over Pd/Mn₃O₄–MnO driven by active sites’ self-tandem catalysis. Environ. Sci. Technol. 2024, 58, 1752–1762.
9.
Vikrant, K.; Chung, M.W.; Boukhvalov, D.W.; et al. A platinum ensemble catalyst for room-temperature removal of formaldehyde in the air. Chem. Eng. J. 2023, 475, 146007.
10.
Qin, X.; Chen, X.; Chen, M.; et al. Highly efficient Ru/CeO₂ catalysts for formaldehyde oxidation at low temperature and the mechanistic study. Catal. Sci. Technol. 2021, 11, 1914–1921.
11.
Sun, X.; Wang, Y.; Cui, J.; et al. Noble-metal-based catalysts on a scale from nanoparticles to subnanoclusters and single atoms for formaldehyde oxidation at room temperature: A review. ACS Appl. Nano. Mater. 2024, 7, 3546–3563.
12.
Bai, B.; Qiao, Q.; Li, J.; et al. Progress in research on catalysts for catalytic oxidation of formaldehyde. Chin. J. Catal. 2016, 37, 102–122.
13.
Shi, L.; Zhou, X.; Guo, Y.; et al. Designing of 3D MnO₂-graphene catalyst on sponge for abatement temperature removal of formaldehyde. J. Hazard. Mater. 2023, 441, 129836.
14.
Wang, M.; Hong, X.; Chen, J.; et al. Two-step hydrothermal synthesis of highly active MnO_x-CeO₂ for complete oxidation of formaldehyde. Chem. Eng. J. 2022, 440, 135854.
15.
Zhang, X.; Guo, L.; Wang, Y.; et al. Y single atoms boost MnO₂ for efficient ambient formaldehyde catalytic oxidation. Sep. Purif. Technol. 2025, 362, 131962.
16.
Fang, R.; Huang, X.; Luo, X.; et al. Excellent stability for catalytic oxidation formaldehyde over defective δ-MnO₂ nanoparticles at room temperature. J. Environ. Chem. Eng. 2023, 11, 109064–109071.
17.
Chen, L.; Li, K.; Xue, T.; et al. Efficient and durable oxidation removal of formaldehyde over layered double hydroxide catalysts at room temperature. Environ. Sci. Technol. 2024, 58, 10378–10387.
18.
Wu, Y.; Guo, Q.; Liu, H.; et al. Effect of Fe doping on the surface properties of δ-MnO₂ nanomaterials and its decomposition of formaldehyde at room temperature. J. Environ. Chem. Eng. 2022, 10, 108277.
19.
Ji, J.; Lu, X.; Chen, C.; et al. Potassium-modulated δ-MnO₂ as robust catalysts for formaldehyde oxidation at room temperature. Appl. Catal. B. Environ. 2020, 260, 118210–118221.
20.
Ma, C.; Yang, C.; Wang, B.; et al. Effects of H₂O on HCHO and CO oxidation at room-temperature catalyzed by MCo₂O4 (M = Mn, Ce and Cu) materials. Appl. Catal. B. Environ. 2019, 254, 76–85.
21.
Li, R.; Huang, Y.; Zhu, Y.; et al. Enhancing oxygen activation ability by composite interface construction over a 2D Co₃O₄-based monolithic catalyst for toluene oxidation. Environ. Sci. Technol. 2024, 58, 14906–14917.
22.
Ma, H.; Yang, W.; Tang, H.; et al. Enhance the stability of oxygen vacancies in SrTiO₃ via metallic Ag modification for efficient and durable photocatalytic NO abatement. J. Hazard. Mater. 2023, 452, 131269.
23.
Xu, C.; Lu, S.; Chen, Y.; et al. Ce-MOFs derived spindle-like MnO₂-CeO₂ heterostructures for enhanced catalytic oxidation of formaldehyde. J. Environ. Chem. Eng. 2026, 14, 122226.
24.
Xing, G.; Liu, X.; Jia, Y.; et al. Oxygen vacancy–rich K-Mn₃O₄@CeO₂ catalyst for efficient oxidation degradation of formaldehyde at near room temperature. J. Colloid. Interf. Sci. 2025, 677, 417–428.
25.
Chen, B.; Shi, C.; Crocker, M.; et al. Catalytic removal of formaldehyde at room temperature over supported gold catalysts. Appl. Catal. B. Environ. 2013, 132–133, 245–255.
26.
Zheng, Y.; Fu, K.; Yu, Z.; et al. Oxygen vacancies in a catalyst for VOCs oxidation: Synthesis, characterization, and catalytic effects. J. Mater. Chem. A. 2022, 10, 14171–14186.
27.
Li, X.; Wang, Y.; Chen, D.; et al. A highly dispersed Pt/copper modified-MnO₂ catalyst for the complete oxidation of volatile organic compounds: The effect of oxygen species on the catalytic mechanism. Green. Energy. Environ. 2023, 8, 538–547.
28.
Wang, H.; Dong, X.; Tang, R.; et al. Selective breakage of CH bonds in the key oxidation intermediates of gaseous formaldehyde on self-doped CaSn(OH)6 cubes for safe and efficient photocatalysis. Appl. Catal. B. Environ. 2020, 277, 119214.
29.
Do, S.-B.; Lee, S.-E.; Kim, T.-O. Oxidative decomposition with PEG-MnO₂ catalyst for removal of formaldehyde: Chemical aspects on HCHO oxidation mechanism. Appl. Surf. Sci. 2022, 598, 153773.
30.
Huang, Y.; Liu, Y.; Wang, W.; et al. Oxygen vacancy–engineered δ-MnO_x/activated carbon for room-temperature catalytic oxidation of formaldehyde. Appl. Catal. B. Environ. 2020, 278, 119294.
31.
Ma, H.; Li, W.; Liu, B.; et al. Oxygen vacancies induced intrinsic electric field attenuation for superior molecular oxygen activation and NO oxidation. Chem. Eng. J. 2025, 505, 159421.
32.
Zhu, G.; Zhu, J.; Jiang, W.; et al. Surface oxygen vacancy induced α-MnO₂ nanofiber for highly efficient ozone elimination. Appl. Catal. B. Environ. 2017, 209, 729–737.
33.
Liu, T.; Ma, X.; Yang, L.; et al. Highly enhanced photocatalytic activity of CaSn(OH)₆ through tuning CaSn(OH)₆/SnO₂ heterostructural interaction and optimizing Fe³⁺ doping concentration. Appl. Catal. B. Environ. 2017, 217, 256–264.
34.
Dong, C.; Yang, C.; Ren, Y.; et al. Local electron environment regulation of spinel CoMn₂O₄ induced effective reactant adsorption and transformation of lattice oxygen for toluene oxidation. Environ. Sci. Technol. 2023, 57, 21888–21897.
35.
Wang, C.; Chen, J.; Li, Q.; et al. Unveiling the position effect of Ce within layered MnO₂ to prolong the ambient removal of indoor HCHO. Environ. Sci. Technol. 2023, 57, 4598–4607.
36.
Xie, J.; Zhang, X.; Zhang, X.; et al. Substitutional C and interstitial N in MnO₂/NC catalysts enable high performance of formaldehyde oxidation at room temperature. J. Environ. Chem. Eng. 2023, 11, 111346.
37.
Wang, J.; Li, J.; Jiang, C.; et al. The effect of manganese vacancy in birnessite-type MnO₂ on room-temperature oxidation of formaldehyde in air. Appl. Catal. B. Environ. 2017, 204, 147–155.

Scilight Press

Author Information

Abstract

Keywords

References

About Scilight

Journals

Publishing Policies

Contact Us