Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted great attention in temperature sensing because of their widespread thermal quenching effect (TQE), a phenomenon in which luminescence intensity decreases as the temperature increases. However, enhancing the TQE of activated ions without changing the dopants or the host is still challenging. Herein, Yb and Er codoped UCNPs in a cubic CaGdF host were synthesized by a coprecipitation method for optical temperature sensing. Compared with the homogeneous shell (CaGdF), those heterogeneous (CaF) shelled UCNPs exhibited stronger upconversion luminescence (UCL) due to the significantly reduced multiphonon nonradiative relaxation. Further, we investigated the effects of homogeneous and heterogeneous shells on TQE. The relationship between the intensity ratio of the green emission bands of Er ions (H → I and S → I) and temperature are obtained for these two core@shell UCNPs. The results demonstrated that the UCNPs with CaF shells are more sensitive to temperature in the 200-300 K. The maximum thermal sensitivity of CaGdF:Yb,Er@CaF could reach 2.2% K at 200 K. These results indicate that the heterogeneous core@shell UCNPs are promising for use as optical temperature sensors.
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http://dx.doi.org/10.1039/d3ra00716b | DOI Listing |
Talanta
December 2024
College of Food Science and Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, China; Laboratory of Quality & Safety Risk Assessment for Agro-Products (Yangling), Ministry of Agriculture and Rural Affairs of the People's Republic of China, Yangling, 712100, China. Electronic address:
In the study, an eccentric heterogeneous core-shell nanomaterial Au@CuSe was simply and rapidly synthesized. This novel nano-structure exhibits superior colorimetric intensity, enhanced antibody coupling efficiency, and strong broadband absorption across the visible to near-infrared spectrum, with a photothermal conversion efficiency of 59.40%.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan, PR China.
The exploration and rational design of high-performance, durable, and non-precious-metal bifunctional oxygen electrocatalysts are highly desired for the large-scale application of overall water splitting. Herein, an effective and straightforward coupling approach was developed to fabricate high-performance bifunctional OER/HER electrocatalysts based on core-shell nanostructure comprising a Ni/NiN core and a NiFe(OH) shell. The as-prepared Ni/NiN@NiFe(OH)-4 catalyst exhibited low overpotentials of 57 and 243 mV at 10 mA cm for the HER and OER in 1.
View Article and Find Full Text PDFChemistry
December 2024
Nantong University, school of chemistry and chemical engineering, Seyuan road, 226019, nantong, CHINA.
FeOOH with excellent catalytic properties for oxygen evolution and also considered to be a true active site has attracted great interest in recent years. However, the intrinsic low conductivity limits its catalytic performance. Herein, a one-dimensional core-shell NiMoO4/FeOOH heterojunction with high OER activity and stability was developed.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
National Local Joint Engineering Research Center for Lithium-ion Batteries and Materials Preparation Technology, Key Laboratory of Advanced Batteries Materials of Yunnan Province, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China. Electronic address:
Achieving efficient catalytic conversion of lithium polysulfides is a key way to improve kinetics in lithium-sulfur (Li-S) batteries. However, due to the limited nature of the catalyst interface, it is difficult to achieve a high conversion rate of LiPSs in one step. A novel heterogeneous dual-chamber core-shell nanocatalyst (CoSe-NiSe@PC) is described here, which efficiently accommodates sulfur and provides a heterogeneous dual catalytic interface like a two-stage "filter".
View Article and Find Full Text PDFACS Nano
December 2024
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Ontario N2L 3G1, Canada.
In contrast to homogeneous enzyme catalysis, nanozymes are nanosized heterogeneous catalysts that perform reactions on a rigid surface. This fundamental difference between enzymes and nanozymes is often overlooked in kinetic studies and practical applications. In this article, using 14 nanozymes of various compositions (core@shell, metal-organic frameworks, metal, and metal oxide nanoparticles), we systematically demonstrate that nontypical features of nanozymes, such as multiple catalytic activities, chemical transformations, and aggregation, need to be considered in nanozyme catalysis.
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