In a study published in the Journal of Advanced Ceramics on May 14, 2025, a research team led by Guiwu Liu from Jiangsu University, China, reported the synthesis of Pt nanoparticle-decorated CoFe2O4/Co3O4 using a solution-based method for the selective detection of formaldehyde (HCHO). The nanosheets were derived from a two-dimensional Fe-Co metal-organic framework (MOF).
The resulting Pt2/CoFe2O4/Co3O4 composite demonstrated strong sensing performance for HCHO, including high sensitivity, selectivity, repeatability, and long-term stability. The sensor responded to HCHO concentrations between 95.5 and 100 ppm at 280 °C and exhibited a detection limit as low as 6 ppb.
Temperature-programmed desorption (TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were used to study HCHO adsorption and desorption on the material surface. Density functional theory (DFT) calculations showed that the Pt2/CoFe2O4/Co3O4 structure had the lowest adsorption energy and was the most stable configuration among those tested.
Theoretical analyses suggested that the material’s sensing ability stems from electron transfer across heterogeneous interfaces and surface reactions with HCHO. The enhanced sensitivity is attributed to the formation of multiple heterojunctions and the catalytic activity of the Pt nanoparticles.
This work presents a straightforward approach to producing high-performance volatile organic compound (VOC) sensors by fabricating MOF-derived heterojunctions decorated with noble metals.
In this work, we synthesized Pt nanoparticles modified CoFe2O4/Co3O4 nanosheets derived by 2D Fe-Co MOF by a facile solution method, and explored the optimal loading capacity of Pt. The Pt2/CoFe2O4/Co3O4 composite exhibits outstanding sensing performance to HCHO, including sensitivity, selectivity, reproducibility, and long-term stability. The Pt2/CoFe2O4/Co3O4 sensor achieves a response of 95.5 to 100 ppm HCHO at 280 ºC and a theoretical LOD of 6 ppb.
Guanjun Qiao, Professor, School of Materials Science and Engineering, Jiangsu University
Additionally, Guanjun Qiao is a senior specialist whose research focuses on gas-sensitive materials and sensors, light-thermal-electrical conversion devices, and advanced ceramics and their composites.
Qiao added, “Two-dimensional metal-organic frameworks (2D MOFs) based on transition metals (Fe, Co, Ni, etc) are considered to be promising self-template gas sensing materials owning to larger specific surface area derived from the porous structure, which can make them have multiple active sites in gas sensing reactions.”
Surface modification with noble metal nanoparticles often leads to significant performance improvements due to the combined effects of enhanced catalytic activity and improved dispersion. Notably, 2D materials can help prevent noble metals from agglomerating, allowing for uniform distribution across the nanosheet surface.
“Using 2D Fe-Co MOFs as a precursor can achieve the effect of killing two birds with one stone,” added Guanjun Qiao.
The Pt2/CoFe2O4/Co3O4 composite demonstrated the strongest response among the samples tested, showing reactivity 14.7, 6.77, and 2.9 times higher than CoFe2O4, Co3O4, and CoFe2O4/Co3O4, respectively. The increased responsiveness of CoFe2O4/Co3O4 is primarily attributed to the formation of p–p junctions.
Additionally, CoFe2O4/Co3O4 synthesized using a 2D MOF template exhibited a reactivity of 33 to HCHO, which is significantly higher than that of bulk CoFe2O4/Co3O4 (20.5). This improvement is due to the larger specific surface area and greater number of reactive sites in the 2D-MOF-derived material.
Qiao noted, “For the Pt2/CoFe2O4/Co3O4, the loading of Pt nanoparticles results in the formation of Schottky heterojunctions with CoFe2O4 and Co3O4, further enhancing the gas sensing performance. Furthermore, the introduced small-sized Pt can act as a catalyst for chemical sensitization to dissociate oxygen molecules, increase the amount of oxygen species adsorbed on the surface, and improve the sensitivity of materials.”
Yuli Zhao, Xiangzhao Zhang, and Guiwu Liu from the School of Materials Science and Engineering at Jiangsu University in Zhenjiang, China; Mingyuan Wang from the School of Mechanical Engineering, Jiangsu University; and Siwei Liu from the Key Laboratory for Theory and Technology of Intelligent Agriculture Machinery and Equipment at Jiangsu University also contributed to the study.
This research was supported by the National Natural Science Foundation of China (Grant No. 51950410596), Jiangsu Province’s Key Research and Development Plan (BE2019094), the Innovation and Entrepreneurship Program (JSSCTD202146), and the Jiangsu Funding Program for Excellent Postdoctoral Talent (2024ZB216).
The research team extends their gratitude to Jiangsu University’s High Performance Computing Platform and the Advanced Computing East China Sub-center for providing the computational resources used in this study.
Journal Reference:
Zhao, Y., et al. (2025). Pt decorated CoFe2O4/Co3O4 nanosheets derived from 2D Fe–Co MOF for enhanced HCHO detection. Journal of Advanced Ceramics. doi.org/10.26599/jac.2025.9221092.
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