10 research outputs found
Exclusive Papers on Environmentally Friendly Catalysis in China
With the development of modern industries, environmental pollution has become a serious and urgent issue [...
A closed-loop process for recycling LiNixCoyMn(1âxây)O2 from mixed cathode materials of lithium-ion batteries
With the rapid development of consumer electronics and electric vehicles (EV), a large number of spent lithium-ion batteries (LIBs) have been generated worldwide. Thus, effective recycling technologies to recapture a significant amount of valuable metals contained in spent LIBs are highly desirable to prevent the environmental pollution and resource depletion. In this work, a novel recycling technology to regenerate a LiNi1/3Co1/3Mn1/3O2 cathode material from spent LIBs with different cathode chemistries has been developed. By dismantling, crushing, leaching and impurity removing, the LiNi1/3Co1/3Mn1/3O2 (selected as an example of LiNixCoyMn(1âxây)O2) powder can be directly prepared from the purified leaching solution via co-precipitation followed by solid-state synthesis. For comparison purposes, a fresh-synthesized sample with the same composition has also been prepared using the commercial raw materials via the same method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements have been carried out to characterize these samples. The electrochemical test result suggests that the re-synthesized sample delivers cycle performance and low rate capability which are comparable to those of the fresh-synthesized sample. This novel recycling technique can be of great value to the regeneration of a pure and marketable LiNixCoyMn(1âxây)O2 cathode material with low secondary pollution. Keywords: Spent lithium-ion battery, Cathode material recycling, Acid leaching, Purification, Co-precipitatio
Low-Loading Sub‑3 nm PtCo Nanoparticles Supported on Co–N–C with Dual Effect for Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells
Developing
low-loading Pt-based catalysts possessing glorious catalytic
performance can accelerate oxygen reduction reaction (ORR) and hence
significantly advance the commercialization of proton exchange membrane
fuel cells. In this report, we propose a hybrid catalyst that consists
of low-loading sub-3 nm PtCo intermetallic nanoparticles carried on
Co–N–C (PtCo/Co–N–C) via the microwave-assisted
polyol procedure and subsequent heat treatment. Atomically dispersed
Co atoms embedded in the Co–N–C carriers diffuse into
the lattice of Pt, thus forming ultrasmall PtCo intermetallic nanoparticles.
Owing to the dual effect of the enhanced metal–support interaction
and alloy effect, as-fabricated PtCo/Co–N–C catalysts
deliver an extraordinary performance, achieving a half-wave potential
of 0.921 V, a mass activity of 0.700 A mgPt–[email protected] V, and brilliant durability in the acidic medium. The fuel cell
employing PtCo/Co–N–C as the cathode catalyst with an
ultralow Pt loading of 0.05 mg cm–2 exhibits an
impressive peak power density of 0.700 W cm–2, higher
than that of commercial Pt/C under the same condition. Furthermore,
the enhanced intrinsic ORR activity and stability are imputed to the
downshifted d-band center and the strengthened metal–support
interaction, as revealed by density functional theory calculations.
This report affords a facile tactic to fabricate Pt-based alloy composite
catalysts, which is also applicable to other alloy catalysts
Sandwich-Structured MXene/Carbon Hybrid Support Decorated with Pt Nanoparticles for Oxygen Reduction Reaction
Carbon
supports for cathodic catalysts in proton-exchange membrane
fuel cells suffer from rapid corrosion and instability; therefore,
alternative supports with a stable structure and a high electric conductivity
are highly required. In this paper, a three-dimensional support hybridized
by MXene and Ketjen Black is developed, in which Ketjen Black is sandwiched
between MXene nanosheets (MCM). After decorating with Pt nanoparticles
by a facile wet-chemical approach, a three-dimensional (3D) Pt/MCM
catalyst is obtained. The intercalated Ketjen Black prevents the stacking
of MXene nanosheets, thus increasing the specific surface area of
the catalyst and exposing the active sites. The strong interaction
between functionalized MXene nanosheets and Pt nanoparticles further
enhances its intrinsic electrocatalytic activity. Pt/MCM demonstrated
encouraging ORR activity with the half-wave potential and specific
activity of 0.892 V and 0.377 mA·cm–2, respectively,
surpassing the state-of-the-art Pt/C catalysts. Especially, Pt/MCM
achieves ultrahigh durability with a 1 mV decrease in half-wave potential
and a 1.73% decrease in mass activity after an accelerated durability
test. Given the performance and structure–activity relationships
of Pt/MCM, it holds great potential for various energy and catalysis-related
applications
The Seventh Visual Object Tracking VOT2019 Challenge Results
The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).Funding Agencies|Slovenian research agencySlovenian Research Agency - Slovenia [J2-8175, P2-0214, P2-0094]; Czech Science Foundation Project GACR [P103/12/G084]; MURI project - MoD/DstlMURI; EPSRCEngineering & Physical Sciences Research Council (EPSRC) [EP/N019415/1]; WASP; VR (ELLIIT, LAST, and NCNN); SSF (SymbiCloud); AIT Strategic Research Programme; Faculty of Computer Science, University of Ljubljana, Slovenia</p