> ## Content Index > Fetch the complete content index at: https://research-pop.com/llms.txt > Use this file to discover other available public pages before exploring further. # Tianjin University-led team turns waste PET into a MOF host for selective PdNi catalysis - URL: https://research-pop.com/tianjin-university-led-team-turns-waste-pet-into-a-mof-host-for-selective-pdni-catalysis/ - Published: 2026-10-27T08:11:20.000Z - Updated: 2026-10-27T08:11:20.000Z - Author: ResearchPOP ![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/10/Screenshot-2026-10-27-at-08.43.12.png) Source: [https://pubs.acs.org/jacsat/article/doi/10.1021/jacs.6c13612/5457014/Low-Temperature-Aqueous-Upgrading-of-Waste-PET](https://pubs.acs.org/jacsat/article/doi/10.1021/jacs.6c13612/5457014/Low-Temperature-Aqueous-Upgrading-of-Waste-PET?ref=research-pop.com) ## At a glance Waste PET bottles can supply the organic building blocks for a catalyst host. A Tianjin University-led collaboration reports an aqueous route to UiO-66 containing confined PdNi clusters, linking plastic upgrading with selective alkyne hydrogenation. For phenylacetylene semihydrogenation to styrene, the catalyst reaches a reported maximum turnover frequency of 67,470 h⁻¹ at 65 °C, nearly 20 times that of a commercial Lindlar catalyst under the authors’ comparison. Spectroscopy, adsorption measurements, kinetic experiments and calculations support a balance between activating phenylacetylene and releasing styrene before it undergoes further hydrogenation. ## Background PET contains terephthalate units that can become building blocks for other materials after the polymer chains are broken down. One possible destination is a metal–organic framework, or MOF: a porous solid assembled from metal-containing nodes and organic linkers. UiO-66 combines zirconium-based nodes with terephthalate linkers, providing a structural connection between PET-derived chemistry and framework synthesis. A MOF can also create a confined environment for catalytic metals. Its pores and coordination sites influence where metal species reside, how they interact and how reactants reach them. This makes the framework both a product of plastic upgrading and a platform for controlling catalytic behavior. The reaction studied here is alkyne semihydrogenation, which adds hydrogen to a carbon–carbon triple bond to produce an alkene. The difficulty is stopping at that stage. In phenylacetylene conversion, the desired styrene can undergo further hydrogenation to ethylbenzene if it remains on the catalyst. Palladium nanoparticles can activate hydrogen and alkynes efficiently, but may also promote this second reaction. Isolated Pd sites offer different adsorption properties, although their activity can be limited. The authors investigate whether small PdNi clusters confined within UiO-66 can combine effective reactant activation with timely product release. ## Research question Can waste PET supply the organic component of UiO-66 through an aqueous preparation route, and can the resulting framework confine associated Pd and Ni species? The catalytic question is whether this cluster environment can balance hydrogen activation, phenylacetylene adsorption and styrene desorption sufficiently well to combine high activity with selective semihydrogenation. ## Inside the study The synthesis begins with waste PET bottle chips. The paper compares pristine chips with material pretreated at 180 °C for 2 h, then uses diffraction to establish formation of UiO-66\. Electron microscopy characterizes the framework morphology, while atomic-resolution imaging and elemental mapping place Pd and Ni in close spatial proximity within the host. The structural argument extends beyond imaging. CO diffuse-reflectance infrared spectroscopy probes adsorption at Pd sites, while Pd and Ni K-edge X-ray absorption measurements examine oxidation state and local coordination. XPS and wavelet-transform EXAFS provide complementary comparisons with metallic and oxide references. Together, these measurements support dispersed Pd associated with Ni in the proposed cluster environment. The catalytic tests compare three materials: Pd clusters associated with Ni in UiO-66, designated PdcNi@UiO-66; isolated Pd associated with Ni, Pd1Ni@UiO-66; and Pd nanoparticles, Pdn@UiO-66\. This comparison asks how changing the local metal arrangement affects both phenylacetylene conversion and the fate of the styrene product. The authors report a maximum turnover frequency of 67,470 h⁻¹ at 65 °C for the cluster catalyst. Separate comparisons in the main figures use 1 mmol phenylacetylene, a mixture of 1.5 mL acetonitrile and 1.5 mL deionized water, and 1.0 MPa H₂, with temperatures of 30 or 130 °C depending on the experiment. These tests address different aspects of performance and should be read under their respective conditions. Alongside conversion and selectivity measurements, the study examines recycling and compares the hydrogenation profiles of phenylacetylene and styrene. Apparent activation energies are determined below 20% conversion, providing a kinetic comparison at an early stage of reaction. Testing styrene separately helps distinguish a catalyst that forms the desired product rapidly from one that also consumes it rapidly. Mechanistic measurements then follow the sequence from hydrogen activation to organic adsorption. Calculated free-energy profiles examine H₂ adsorption and activation, while hydrogen temperature-programmed desorption and reaction-order measurements provide experimental context. Isothermal titration calorimetry measures phenylacetylene binding, and in situ infrared spectroscopy follows surface species during hydrogenation. DFT calculations compare phenylacetylene adsorption and charge redistribution on nanoparticle, cluster and isolated-site models. They also examine the competition that determines selectivity after styrene forms: desorption into solution versus continued hydrogenation on the surface. The authors interpret the combined evidence through a moderate-adsorption mechanism. The PdNi cluster provides sufficient interaction with phenylacetylene to support conversion while favoring styrene release over further hydrogenation to ethylbenzene. In this picture, the benefit arises from balancing successive steps across the reaction pathway. ## Takeaways and outlook The study connects a waste-derived feedstock, a porous host and a confined catalytic structure. PET supplies the organic component for UiO-66, while the framework provides an environment in which Pd and Ni can cooperate during selective hydrogenation. Its mechanistic contribution is the connection between local metal structure and the balance of reactant binding and product release. The cluster comparison shows why high activity alone is insufficient: a useful semihydrogenation catalyst must also allow the alkene to leave before additional hydrogen is incorporated. The work demonstrates PET-to-MOF upgrading and catalytic performance under defined laboratory conditions. Establishing the wider process value will require assessment of material and energy inputs, catalyst recovery, longer operation and performance across additional substrates and waste-feed compositions. ## About the researchers Jing Du of Tianjin University is the first author. Shaopeng Li and Meiting Zhao of Tianjin University, together with Jun Guo of Tiangong University, are the corresponding authors. Qianjin Guo, Shengzhe Jia, Zefei Dong, Qi Zhang and Wansheng Yue are affiliated with Tianjin University. Caoyu Yang is affiliated with the National Center for Nanoscience and Technology, and Yongli Ji with Tiangong University. ## Original research Jing Du; Caoyu Yang; Qianjin Guo; Yongli Ji; Shengzhe Jia; Zefei Dong; Qi Zhang; Wansheng Yue; Shaopeng Li; Jun Guo; Meiting Zhao. “Low-Temperature Aqueous Upgrading of Waste PET Plastics into Metal-Organic Frameworks with Confined PdNi Clusters for High-Performance Semihydrogenation of Alkynes.” *Journal of the American Chemical Society*. Published online 23 October 2026. Original paper: [https://doi.org/10.1021/jacs.6c13612](https://doi.org/10.1021/jacs.6c13612?ref=research-pop.com) --- ## Research POP Notes This article reflects the independent interpretation of the Research POP team and does not represent the views of the authors, their institutions or the journal. If you identify any inaccuracies or have concerns regarding the content, figures or attribution, please contact us at [team.researchpop@gmail.com](mailto:team.researchpop@gmail.com). We will review the matter promptly and make corrections or remove the relevant material where appropriate.