Jinna Guo,Mingsen Xie,Peiyao Du,Yu Liu,Xiaoquan Lu
Luminol, as a classical luminophore, plays a crucial role in electrochemiluminescence (ECL). However, the traditional luminol–H2O2 ECL system suffers from the self-decomposition of H2O2 at ambient temperature, which hinders its further application in quantitative analysis. In this work, for the first time, we developed atomically gold-supported two-dimensional VO2 nanobelts (Au/VO2) as an advanced co-reaction promoter to speed up the reduction of dissolved oxygen to superoxide radicals (O2•–), which react with the luminol anion radical and greatly promote the ECL emission. The ECL resonance energy transfer (ECL-RET) between the hollow manganese dioxide nanospheres and luminol results in a conspicuously decreased ECL signal response, and in the presence of glutathione (GSH), effective redox reaction between manganese dioxide and GSH restores the ECL signal. As a consequence, the designed sensor based on ECL-RET-assisted Au/VO2 signal amplification showed outstanding performance for “signal-on” detection of GSH in the concentration range of 10–3 to 10–10 M, and the detection limit was as low as 0.03 nM. The ECL sensor displayed excellent specificity and was successfully utilized to target GSH in real human serum samples. Importantly, this work not only highlights a powerful avenue for constructing an ultrasensitive ECL sensor for GSH but also provides some inspiration for the further design of high-performance co-reaction accelerators using the ECL technique.
Lithium–sulfur (Li–S) batteries have attracted wide attention as high-energy-density energy storage devices, but their practical applications are hindered by the severe shuttle effect and sluggish kinetics of lithium polysulfides (LiPSs). To address these challenges, polar mediators are employed to chemisorb and catalyze LiPSs, but most of them suffer from low electronic conductivity and poor catalytic activity. Here, a novel strategy is reported to enhance both properties by dispersing Fe(III) atoms in VO 2 nanoribbons(Fe-VO 2 ), creating electronic metal-support interactions (EMSI) that modulate the electronic structure and charge transfer of VO 2 . Theoretical calculations reveal that EMSI lowers the energy barrier for the decomposition of Li 2 S from 1.60 to 1.32 eV and increases the electronic conductivity of VO 2 . Fe doping reduces the Li-ions diffusion barrier from 1.42 eV in VO 2 to 0.99 eV in Fe-VO 2 . The Fe-VO 2 catalyst shows strong adsorption and fast converstion of LiPSs, resulting in high energy density and long cycling life of Li-S batteries. The cathode with Fe-VO 2 maintains a higher capacity retention of 67% after 500 cycles at 1 C, compared with 52.4% and 53.6% for the carbon black based cathode and VO 2 based cathode, respectively. This work demonstrates the potential of EMSI for designing efficient catalysts for Li–S batteries and provides new insights into the electronic structure engineering of polar mediators.
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