Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Aug 5;12(15):2697.
doi: 10.3390/nano12152697.

Efficient Electrocatalyst Nanoparticles from Upcycled Class II Capacitors

Junhua Xu  1   2 , Daobin Liu  1 , Carmen Lee  1 , Pierre Feydi  3 , Marlene Chapuis  3 , Jing Yu  1   4 , Emmanuel Billy  3 , Qingyu Yan  1   4 , Jean-Christophe P Gabriel  1   5
Affiliations

Efficient Electrocatalyst Nanoparticles from Upcycled Class II Capacitors

Junhua Xu et al. Nanomaterials (Basel). .

Abstract

To move away from fossil fuels, the electrochemical reaction plays a critical role in renewable energy sources and devices. The anodic oxygen evolution reaction (OER) is always coupled with these reactions in devices but suffers from large energy barriers. Thus, it is important for developing efficient OER catalysts with low overpotential. On the other hand, there are large amounts of metals in electronic waste (E-waste), especially various transition metals that are promising alternatives for catalyzing OER. Hence, this work, which focuses on upcycling Class II BaTiO3 Multilayer Ceramic Capacitors, of which two trillion were produced in 2011 alone. We achieved this by first using a green solvent extraction method that combined the ionic liquid Aliquat® 336 and hydrochloride acid to recover a mixed solution of Ni, Fe and Cu cations, and then using such a solution to synthesize high potential catalysts NiFe hydroxide and NiCu hydroxide for OER. NiFe-hydroxide has been demonstrated to have faster OER kinetics than the NiCu-hydroxide and commercial c-RuO2. In addition, it showed promising results after the chronopotentiometry tests that outperform c-RuO2.

Keywords: ceramic capacitor; circular economy; electrocatalysis; electronic waste; ionic liquid; layered double hydroxide; liquid-liquid extraction; nanoparticle; nickel; re-use; recycling.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
The experimental process of recycling metals from waste MLCC and the observed 4 domains (zone 1 = solid phase; zone 2 = aqueous phase; zones 3 and 4 = IL phases to be back-extracted).
Figure 1
Figure 1
(a) Concentrations of metals after the multistep back-extraction process for zone 3. (b) Concentrations of metals after the multistep back-extraction process for zone 4.
Scheme 2
Scheme 2
Simultaneous multi-zone leaching and extraction of valuable metals from waste MLCC by Aliquat® 336-HCl-H2O system.
Figure 2
Figure 2
(a) The XRD patterns and SEM images. (b) NiFe-hydroxide, (c) NiCu-hydroxide and (d) Ni-LDH TEM images. (e) NiFe-hydroxide, (f) NiCu-hydroxide, (g) Ni 2p, (h) Fe 2p, and (i) O 1s XPS spectra.
Figure 3
Figure 3
(a) Linear sweep voltammetry (LSV) curves of as-prepared nanoparticles of NiFe-hydroxide, NiCu-hydroxide and commercial c-RuO2 catalysts in 1 M KOH electrolyte. (b) The corresponding Tafel plots derived from LSV curves. (c) Nyquist plots recorded for NiFe-hydroxide and c-RuO2 at an applied potential of 1.50 V (vs. RHE). (d) Chronopotentiometric curve for NiFe-hydroxide and c-RuO2 at a constant current density of 20 mA cm−2 for more than 20 h in 1 M KOH.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Xu J., Chen C., Han Z.F., Yang Y.Y., Li J.S., Deng Q.B. Recent Advances in Oxygen Electrocatalysts Based on Perovskite Oxides. Nanomaterials. 2019;9:1161. doi: 10.3390/nano9081161. - DOI - PMC - PubMed
    1. Zhou Y., Wang Z., Pan Z., Liu L., Xi J., Luo X., Shen Y. Exceptional Performance of Hierarchical Ni–Fe (hydr)oxide@NiCu Electrocatalysts for Water Splitting. Adv. Mater. 2018;31:e18067692. doi: 10.1002/adma.201806769. - DOI - PubMed
    1. Baldé K., Wang F., Kuehr R., Huisman J. The Global E-Waste Monitor—2014. United Nations University, IAS—SCYCLE; Bonn, Germany: 2015.
    1. Rai V., Liu D., Xia D., Gabriel J.C.P. Electrochemical Approaches for the Recovery of Metals from Electronic Waste, a Critical Review. Recycling. 2021;6:53. doi: 10.3390/recycling6030053. - DOI
    1. Chen Z., Yang M., Shi Q., Kuang X., Qi H.J., Wang T. Recycling Waste Circuit Board Efficiently and Environmentally Friendly through Small-Molecule Assisted Dissolution. Sci. Rep. 2019;9:17902–17910. doi: 10.1038/s41598-019-54045-w. - DOI - PMC - PubMed

LinkOut - more resources