IMB-CNM Thesis Defense: Metal nanoparticle carbon nanocomposites to produce electrochemical devices for environmental water monitoring
Author: Wenchao Duan
Directors:
- César Fernández (IMB-CNM)
- Martí Gich (ICMAB)
PhD Comittee:
- President: Margarita Darder Colom, Inst. Ciencia de Materiales de Madrid (ICMM), CSIC, Spain
- Secretary: Dino Tonti, ICMAB, CSIC, Spain
- Vocal: Gillaume Suárez, Lausanne University, Switzerland
Abstract
The intensive monitoring of water quality enforced by new wastewater management directives calls for the development of fast and low-cost analytical platforms that enabled timely and robust detection of a variety of chemical pollutants. Electrochemical sensors are poised to become alternative technologies for the sensitive analysis of environmentally relevant chemicals due to the merits of low-cost, rapid detection, simplicity, portability, low power requirements, safety of operation and potential in-situ and semi-continuous analysis. In this context, this thesis focuses on developing low-cost and easy-to-use miniaturized electrochemical sensors for the analysis of the organic matter, halogenated compounds and heavy metals in waters. For this purpose, several functional materials are tailored synthesized and processed to fabricate thick-film and thin-film sensors by screen-printing and lithography available industrial processes.
Three electrode composite materials are prepared that comprise a porous carbon matrix and metal or metal oxide nanoparticles. Several sol-gel chemical synthesis approaches are studied to produce a carbon copper-based nanoparticle nanocomposite material. With the aim of contributing to the circular economy and looking at a more sustainable alternative for producing these materials, a silver nanoparticle-doped porous carbon matrix is prepared using bread waste impregnated with a silver nanoparticle precursor. Also, porous carbon composites are prepared from wood by-products and further modified with bismuth nanoparticles.
The developed materials are electrochemically evaluated using paste electrodes before producing large batches of commercial-like screen-printed single-use electrodes that are applied to the detection of the already mentioned target analytes.
Thin-film carbon electrodes are also produced on Si/SiO2 substrates by a combined sol-gel material synthesis and photolithography/dry etching process at the wafer level. Conventional three-electrode electrochemical cells of planar configuration are produced and developed as sensor devices for detecting organic load by electrodepositing copper nanoparticles (Cu NPs) on the working electrode under controlled potentiostatic conditions. In addition, a simple fluidic device is fabricated that includes a flow cell to integrate the thin-film carbon electrodes and carry out the Cu NPs electrodeposition and organic load detection in an automatic fashion.