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. The adsorption and desorption of HCHO on the surface of sensing materials were investigated by TPD and in-situ DRIFTs. The DFT calculations demonstrate that the Pt2/CoFe2O4/Co3O4 is the most stable structure and has the lowest adsorption energy. Moreover, the gas sensing mechanisms including electron transfer at heterogeneous interfaces and the reaction of HCHO on the surface of materials are proposed by band theory and DFT calculations. The excellent sensitivity to HCHO is mainly attributed to the formation of multi-heterojunctions and the catalytic effect of Pt. This work provides a new perspective to fabricate high-performance VOC sensors by constructing multi-heterojunctions decorated by noble metals.
Recently, a team of material scientists led by Guiwu Liu from Jiangsu University, China reported Pt nanoparticles decorated CoFe2O4/Co3O4 nanosheets were prepared by solution method for highly accurate detection of formaldehyde (HCHO), where the CoFe2O4/Co3O4 nanosheets were derived from two-dimensional Fe-Co metal-organic framework (MOF). The ternary composite also presents excellent reproducibility, selectivity and long-term stability. The first-principles calculations demonstrate that the Pt/CoFe2O4/Co3O4 model presents the most stable structure and the strongest adsorption capacity for HCHO. The high sensitivity of Pt/CoFe2O4/Co3O4 to HCHO can be mainly ascribed to the formation of multi-heterojunctions and the catalytic effect of Pt nanoparticles. This work provides a facile preparation of MOF-derived multi-heterojunction materials, and highlights superior gas-sensing performances to VOCs.
The team published their work in Journal of Advanced Ceramics on May 14, 2025.
"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."said Guanjun Qiao, professor at School of Materials Science and Engineering at Jiangsu University (China), a senior expert whose research interests focus on the field of advanced ceramics and their composites, light-thermal-electrical conversion materials and devices, gas-sensitive materials and gas sensors.
"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 structur, which can make them have multiple active sites in gas sensing reactions." said Guanjun Qiao.
The surface modification of noble metal nanoparticles usually has a significant improvement due to the synergy of multiple effects such as catalytic properties. Indeed, 2D materials can effectively avoid the agglomeration of noble metals, so that they grow uniformly on the surface of nanosheets. "Using 2D Fe-Co MOFs as a precursor can achieve the effect of killing two birds with one stone." said Guanjun Qiao.
The Pt2/CoFe2O4/Co3O4 exhibits the highest response than the other three samples, which is 14.7, 6.77 and 2.9 times higher than those of CoFe2O4, Co3O4 and CoFe2O4/Co3O4, respectively. The higher response of CoFe2O4/Co3O4 is mainly attributed to the formation of p‒p junctions. The response of CoFe2O4/Co3O4 (33) to HCHO is significantly higher than that of bulk CoFe2O4/Co3O4 (20.5), which is due to the larger specific surface area and more reactive sites of CoFe2O4/Co3O4 synthesized using 2D MOF as template. "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." said Guanjun Qiao.
Other contributors include Yuli Zhao, Xiangzhao Zhang, 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, Zhenjiang, China; Siwei Liu from the Key Laboratory for Theory and Technology of Intelligent Agriculture Machinery and Equipment, Jiangsu University, Zhenjiang, China.
This work was supported by National Natural Science Foundation (51950410596) of China, and the Key Research and Development Plan (BE2019094), Innovation/Entrepreneurship Program (JSSCTD202146) of Jiangsu Province, Jiangsu Funding Program for Excellent Postdoctoral Talent (2024ZB216). We thank the High Performance Computing Platform of Jiangsu University and Advanced Computing East China Sub-center for providing the facility support on the numerical calculations in this paper.
About Author
Guanjun Qiao: Professor and doctoral supervisor of the School of Materials Science and Engineering, Jiangsu University, obtained his Ph.D. from Xi 'an Jiaotong University in 1995. He/She was selected as a leading talent of the second batch of the National Ten Thousand Talents Program, a member of the National Hundred, Thousand and Ten Thousand Talents Project, and the first tier of Jiangsu Province's "333 Talent Project", and was awarded the Government Special Allowance of The State Council. It mainly focuses on advanced ceramics and their composite materials, light-heat-electricity conversion materials and devices, gas-sensitive materials and gas sensors, etc. As the first finisher, he/she won the second prize of the National Technological Invention Award. Leading the team, more than 300 SCI papers were published in journals such as JACS, Adv Funct Mater, and ACS Nano, and more than 70 invention patents were authorized. More than 40 postdoctoral and doctoral graduates have been trained.
Guiwu Liu: Professor and doctoral supervisor of the School of Materials Science and Engineering, Jiangsu University, obtained his Ph.D. from Xi 'an Jiaotong University in 2008. Selected for the Ministry of Education's New Century Excellent Talent Support Program, a high-level talent in Jiangsu Province's Six Major Talent Peaks, and a core member of Jiangsu Province's innovation and entrepreneurship teams, etc. The main focus is on the research of high-temperature wetting and welding of ceramics, gas-sensitive materials and gas sensors, as well as photo-thermol-electrical conversion materials and their devices. As the first author or corresponding author in Adv Funct Mater, ACS Nano, J Adv Ceram, Nano Energy, Chem Eng J, Sens Actuators B Chem, J Eur Ceram Soc, Appl Phys More than 200 SCI papers have been published in well-known domestic and international journals such as lett, with over 5,000 citations from others. As the first inventor, more than 20 invention patents have been authorized.
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen . JAC's 2023 IF is 18.6, ranking in Top 1 (1/31, Q1) among all journals in "Materials Science, Ceramics" category, and its 2023 CiteScore is 21.0 (top 5%) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
