Waste solar silicon repurposed as support for palladium nanoparticle catalysts

<p>A research team from Italy has developed a novel approach to upcycle silicon (Si) recovered from end-of-life (EoL) PV modules and use it as a support material for palladium (Pd) nanoparticle catalysts.</p>

<p>The recycled silicon is intended for use in Pd/Si catalysts in microwave-assisted Suzuki–Miyaura cross-coupling reactions for biaryl synthesis, a widely employed process in the production of pharmaceuticals and agrochemicals.</p>

<p>“Following the established recovery protocol for metallurgical-grade silicon (MG-Si) from EoL photovoltaic modules, we herein demonstrate a value-added application of this e-waste-derived material as a support for palladium nanoparticles,” the group explained. “The resulting Pd/Si material serves as an efficient heterogeneous catalyst for Suzuki–Miyaura cross-coupling reactions, providing access to biaryl motifs that are key structural units in several important compounds, such as tepotinib, boscalid, and the Sartan class.”</p>

<p>For their novel approach, the researchers developed a heterogeneous catalyst by depositing palladium nanoparticles onto MG-Si, the form of silicon typically recovered from end-of-life PV modules after recycling. The material was characterized using scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and chemisorption analysis before being evaluated in microwave-assisted Suzuki–Miyaura cross-coupling reactions.</p>

<p>The team optimized the reaction conditions and found that a γ-valerolactone (GVL)/water (9:1) solvent mixture, potassium pivalate as the base, and a 0.5 mol% palladium loading enabled complete conversion within 40 minutes under microwave irradiation. The researchers also assessed the catalyst across a broad range of substrates, evaluated its recyclability over multiple reaction cycles, and performed a life-cycle assessment comparing PV-waste-derived silicon with virgin silicon and activated carbon supports.</p>

<p>“The catalyst Pd/Si was thoroughly characterized, confirming that Pd is predominantly present as metallic Pd⁰ nanoparticles with an average particle size of 4.8 ± 1.1 nm, well-dispersed on the silicon surface,” the researchers reported. “The Pd/Si was employed in the Suzuki–Miyaura cross-coupling reaction under microwave irradiation, effectively minimizing hot-spot formation.”</p>

<p>Under optimized conditions, Pd/Si enabled the synthesis of 24 biaryl compounds, including three key intermediates used in the production of sartans and boscalid. The researchers evaluated scalability through a 10 mmol synthesis of 4-formylbiphenyl, a model biaryl product obtained by coupling 4-bromobenzaldehyde with phenylboronic acid. The reaction maintained its performance under microwave irradiation, achieving a 97% isolated yield and an E-factor of 2.6. The corresponding energy-related E⁺-factor was calculated at 35.9.</p>

<p>“The Pd/Si catalyst exhibited excellent recyclability over 6 consecutive runs, with Pd leaching ranging from 0.6 to 0.1 ppm across 5 runs, then increasing in the 6th run,” the academics concluded. </p>

<p>Their work “<a href="https://www.sciencedirect.com/science/article/pii/S2352554126001907" rel="noreferrer noopener" target="_blank">From waste to wealth: Silicon upcycling for sustainable palladium nanoparticle catalysts in cross-coupling reaction</a>” appeared <em>in Sustainable Chemistry and Pharmacy. </em>The scientists were from Italy’s <a href="https://www.pv-magazine.com/2026/06/12/the-hydrogen-stream-wartsila-testing-100-hydrogen-engine/" rel="noreferrer noopener" target="_blank">University of Perugia</a>, <a href="http://Mediterranea University of ​​Reggio Calabria" rel="noreferrer noopener" target="_blank">Mediterranea University of ​​Reggio Calabria</a>, the <a href="https://www.pv-magazine.com/2026/04/06/new-time-targets-large-scale-perovskite-production-in-italy/" rel="noreferrer noopener" target="_blank">Italian National Research Council</a>, and the <a href="https://www.pv-magazine.com/2026/02/09/the-impact-of-agrivoltaics-on-potato-farming/" rel="noreferrer noopener" target="_blank">University of Florence</a>.</p>

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<p>The post <a href="https://www.pv-magazine.com/2026/08/04/waste-solar-silicon-repurposed-as-support-for-palladium-nanoparticle-catalysts/">Waste solar silicon repurposed as support for palladium nanoparticle catalysts</a> appeared first on <a href="https://www.pv-magazine.com">pv magazine Global</a>.</p>