Pd Leaching Research Articles

Magnetic covalent hybrid of graphitic carbon nitride and graphene oxide as an efficient catalyst support for immobilization of Pd nanoparticles

For the first time a magnetic carbon based hybrid catalyst, Pd@g-C3N4-Fe-GO, is prepared through covalent conjugation of magnetic graphitic carbon nitride and graphene oxide followed by incorporation of Pd nanoparticles. First, the formation of the catalyst was confirmed via XRD, TG, BET, TEM, FTIR, ICP and VSM analyses and then its catalytic activity for promoting Suzuki and Sonogashira coupling reactions under mild reaction condition was investigated. To elucidate whether hybridization of two carbon materials could improve the catalytic activity, the catalytic activity of the catalyst was compared with the control catalysts (Pd@g-C3N4 -GO, Pd@g-C3N4-Fe, Pd@ Fe-GO, Pd@g-C3N4, Pd@GO and the GO/g-C3N4 physical hybrid). Moreover, the role of magnetic nanoparticles in the catalytic performance was confirmed. Notably, the catalytic activities of the catalyst and the control sample prepared via physical hybridization of two carbon materials were compared to confirm the effect of covalent conjugation on the catalytic activity. Moreover, the study of the substituent effect of p-substituted phenyl iodides was considered by Hammett plot, which revealed a beneficial effect of electron-withdrawing side groups for the CC coupling reaction. Finally, the recyclability of Pd@g-C3N4-Fe-GO as well as leaching of Pd and magnetic nanoparticles was studied.

Halloysite nanoclay decorated with 2-amino pyrimidine functionalized poly glycidyl methacrylate: An efficient support for the immobilization of Pd nanoparticles

Taking advantage of the synergistic effects between polymer (P) and halloysite clay (Hal) as well as the capability of heteroatom-containing polymers for anchoring nanoparticles and suppressing their leaching, a novel support composed of Hal and 2-amino pyrimidine (Py) functionalized poly glycidyl methacrylate (P) was prepared through initial functionalization of Hal followed by polymerization with glycidyl methacrylate and functionalization with 2-amino pyrimidine. The support (Hal-P-Py) was then used for the immobilization of Pd nanoparticles to afford a heterogeneous catalyst (Pd@Hal-P-Py) with high catalytic activity for Sonogashira coupling reaction under mild and eco-friendly reaction condition. Preparing various control catalysts, i.e. Pd@Hal-P, Pd@Hal, Pd@P and Pd@P-Py, and comparing their catalytic activities with that of the catalyst, the contribution of polymer and 2-amino pyrimidine to the catalysis was confirmed. Noteworthy, the catalyst was recyclable and could be recovered and used up to six times with insignificant loss of the catalytic activity and Pd leaching. Moreover, hot filtration experiment confirmed the heterogeneous nature of the catalysis.

Selective catalytic hydrogenation of phenol to cyclohexanone over Pd@CN: Role of CN precursor separation mode

AbstractThe one‐step hydrogenation of phenol to cyclohexanone is green and sustainable. In this study, the effect of a CN (N‐doped carbon) precursor separation mode on the catalytic performance of a Pd@CN catalyst for selective hydrogenation of phenol to cyclohexanone in water was investigated. Three modes, i.e., rotary evaporation, centrifugation, and filtration, were designed to separate the CN precursor while preparing the Pd@CN catalyst. The results highlight that the separation mode significantly affects the phenol hydrogenation performance of the Pd@CN catalyst. The best catalytic performance is obtained when separating the CN precursor by the rotary evaporation mode. Based on a series of characterizations, it is confirmed that the separation mode of rotary evaporation can introduce more N into the mesoporous carbon, improve the Pd dispersion, and enhance the basic sites and Pd loading, leading to higher catalytic activity. Furthermore, the Pd@CN catalyst prepared by rotary evaporation exhibits better catalytic stability. Less Pd leaching is responsible for its slight deactivation. These findings can provide a point of reference for the development of Pd@CN catalysts with high catalytic performance.

Immobilization of palladium nanoparticles on Metformin-functionalized graphene oxide as a heterogeneous and recyclable nanocatalyst for Suzuki coupling reactions and reduction of 4-nitrophenol

In this study, Pd nanoparticles supported on Metformin modified graphene oxide (GO-Met-Pd) is proposed as a green heterogeneous catalyst. The structural properties of the as-synthesized nanocatalyst were determined by X-ray diffraction (XRD), Fourier transformed infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), wavelength-dispersive X-ray spectroscopy (WDX) and inductively coupled plasma (ICP). Activity of the catalyst was investigated by focusing on the Suzuki-Miyaura coupling reaction and room-temperature reduction of 4-nitrophenol (4-NP), as model reactions. The catalyzed reactions provided high yields of biphenyl compounds through the Suzuki-Miyaura reaction and outlined highly efficient conversion of 4-NP to its reduced form. Moreover, no significant Pd leaching was detected in the reaction solutions and the catalyst could be recovered, at least, 6 times without any considerable loss of its catalytic activity.

Catalysis mechanism of Pd(II)@PVA membrane catalyst studied from the aspect of molecular level micro-defects by positron annihilation spectroscopy

In this study, an insightful understanding of the correlations of the molecular level micro-defects structure and catalytic performance of palladium species supported on polyvinyl alcohol (Pd(II)@PVA) membrane heterogeneous catalyst have been studied with positronium probe and other structural characterization methods. The micro-defects size both in crystalline region (Dc) and amorphous region (Da) of PVA matrix increases gradually with the Pd species loading and membrane catalyst recycle times. As a result of a synergism of micro-defects enlargement caused by solvents swelling and highly thermal motions of macromolecular segments at high temperature, a number of instantaneously connected micro-defects channel rather than a single micro-defect in the real reaction state might provide enough open spaces for the coupling reactions. This catalysis mechanism from the aspect of molecular level micro-defects structure is powerfully supported by comparing the catalytic performances of a common Pd(II)@PVA membrane catalyst and a PVA layer sealed Pd(II)@PVA membrane catalyst applied in Heck reactions. As the recycle times increases, the compactness and regularity of PVA molecular chain segments stacking decreases obviously, which promotes the Pd leaching and causes gradually decrease in catalytic efficiency of the recycled Pd(II)@PVA membrane catalyst. The mechanical properties, morphology, crystalline behavior, and swelling properties of the Pd(II)@PVA membrane catalysts are also characterized and explained in view of the changes of molecular level micro-defects structure.

Recyclable cellulose nanocrystal supported Palladium nanoparticles as an efficient heterogeneous catalyst for the solvent‐free synthesis of coumarin derivatives via von Pechmann condensation

2‐Amino pyrimidine nanocellulose‐supported Palladium nanoparticles (CNC‐AMPD‐Pd) as a novel bio supported nanocatalyst was prepared and characterized by ICP‐AES, FT‐IR, XRD, SEM, TEM, TGA and EDX techniques. The nanocatalyst demonstrated outstanding performance in Pechmann condensation between different substituted phenols and ethyl acetoacetate to obtain coumarin derivatives in good to excellent yields. The catalyst is easily recycled and reused without loss of the catalytic activity. The combined merits of reusable catalyst and solvent‐free reaction conditions make the condensation with safe operation, no leaching of pd into environment, low pollution, rapid access to products and simple workup.

Research Update: Distribution and stabilization of Pd catalysts in porous carbon-based supports by aggregation of pre-doped colloidal particles

In this work, the synthesis of a stable supported Pd catalyst by aggregation of colloidal particles (CPs) of polyacrylonitrile (PAN) containing the noble metal is discussed. The metal is initially incorporated during the polymerization reaction (0.5 wt. %) and results to be well embedded inside the polymeric structure and anchored to the nitrogen atom of acrylonitrile. Moreover, aiming to provide free access towards the catalyst active sites, a KOH-activated heat treatment was performed on the PAN CP aggregates, thus creating pore sizes between 0.7 and 5 nm with surface area SBET = 1150 m2/g. After the harsh heat treatment, the amount of Pd remaining in the pyrolyzed polymer is 2.8 wt. %, as measured by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), which then corresponds to a total weight loss of 83% (assuming no loss of Pd). This result indicates a remarkable stability of Pd inside the polymer structure and that minimal Pd leaching can be expected during the catalyst use. X-ray absorption spectroscopic studies of pyrolyzed Pd-containing PAN and following extended X-ray absorption fine structure fitting showed no sign of bulk Pd(0), while a dominant proportion of Pd is present as dispersed Pd carbides. These results are consistent with the data obtained using X-ray absorption near edge structure. Finally, the catalyst was tested on a Suzuki coupling in the liquid phase and showed good activity, hence proving the accessibility of the active sites to reactants.

Batch to continuous photocatalytic degradation of phenol using TiO2 and Au-Pd nanoparticles supported on TiO2

A series of Au-Pd/TiO2 catalysts were synthesized in different weight % using sol-immobilization method. Of the range studied 1%Pd/TiO2 catalyst achieved 86.4% conversion of phenol to CO2 in a standard batch-slurry system utilizing UV. However under recycle or continuous operation Pd leaching from catalyst surface led to gradual deactivation. Au-Pd nanoparticles supported on TiO2 P25 were stable and recyclable, here Au species were found to help to anchor Pd species on TiO2, and no observable Pd leaching occurred. Utilizing UV, 1%Pd/TiO2 showed faster rate of phenol degradation in comparison to Au-Pd/TiO2, while 1%Au/TiO2 and 0.5%Au-0.5%Pd/TiO2 showed faster phenol degradation rates under visible light. The TiO2 P25 support was also found to be active, stable and recyclable in phenol degradation utilizing UV; and was hence considered suitable for continuous operation. However poor oxygen mass transfer led to the formation and lay-down of polymeric species when using a Trickle bed approach. Operation in the Taylor flow regime was demonstrated to increase oxygen saturation and significantly reduced deactivation. Hence continuous photocatalytic degradation of phenol could be achieved using TiO2 under Taylor Flow conditions.

Polymer‐supported palladium (II) containing N2O2: An efficient and robust heterogeneous catalyst for C–C coupling reactions

ABSTRACTA new polymer was prepared from 1,3,5‐triformylphloroglucinol (noted as TDTB) and o‐phenylenediamine through Schiff base condensation reaction, and palladium (II) was immobilized on the polymer (noted as TbPo‐Pd(II)). This process was easy to work‐up and cost‐effective. The structure and composition of TbPo‐Pd(II) were fully characterized by FTIR, TGA, XPS, AAS, SEM, and TEM analyses. Meanwhile, this catalyst showed desired thermal stability and excellent performance in water/methanol system for Suzuki and Sonogashira coupling reactions. In addition, this heterogeneous catalyst can be readily recovered by simple filtration with no appreciable Pd leaching in the reaction. This work provides a powerful protocol for rapid access to asymmetrical biphenyls and aryl alkynes. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2344–2353

Dechlorination of triclosan by enhanced atomic hydrogen-mediated electrochemical reduction: Kinetics, mechanism, and toxicity assessment

Environmental-friendly and efficient technologies for the removal of halogenated organic compounds in water are highly desired. Triclosan (TCS) is a potential threat to the environment and human health, and is resistant to biodegradation. Here, a Pd/N-GR/Cu foam exhibits a much enhanced activity as the cathode for TCS degradation by electrochemical reduction. The dechlorination rate of Pd/N-GR/Cu foam is 5.50, 6.49, and 14.68 times higher than Pd/Cu, N-GR/Cu, and Cu foam, respectively. The leaching of Pd and Cu is inhibited due to the protection by cathodic currents and alkaline conditions. 2- and 1-chlorinated isomers are the main intermediates, and the final products are completely dechlorinated 2-phenoxyphenol with a small amount of further H radical addition product 6-phenoxycyclohex-3-enol. ESR spin trapping results indicate the coupling of Pd and N-GR promotes the production and utilization of atomic H*, and the contribution of atomic H* obeys the order of Pd/N-GR/Cu (68.5%) > Pd/Cu (56.6%) > N-GR/Cu (24.3%) > Cu (5.7%). The bacterial cytotoxicity and AhR activity of TCS solution after 60 min are decreased by 83.2% and 90.3%, respectively. The electrochemical reduction can be a promising option for supplementing the current technologies for TCS abatement in wastewater.

Pd nanoparticles immobilized on the poly-dopamine decorated halloysite nanotubes hybridized with N-doped porous carbon monolayer: A versatile catalyst for promoting Pd catalyzed reactions

A hybrid catalyst, Pd@Hal-pDA-NPC, with the utility for promoting both CC coupling reactions (Sonogashira, Heck and Suzuki reactions) and hydrogenation of nitrocompounds is prepared through two main steps. First, Pd(0) nanoparticles was immobilized on the poly-dopamine decorated halloysite nanotubes (Hal-pDA) and then Pd@Hal-pDA was hybridized with the layers of a novel multi-N-doped porous carbon monolayer derived from 4,4′,4″-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tribenzonitrile. The results established that the catalyst could catalyze all the reactions efficiently under mild reaction condition. Moreover Pd@Hal-pDA-NPC exhibited high recyclability (up to ten reaction runs). Using various control catalysts, precise stuy was performed to elucidate the role of NPC and p-DA in the catalysis and suppressing Pd leaching. The results confirmed that both NPC and p-DA could improve Pd loading, while supress its leaching. Moreover, it was proved that incorporation of NPC was more effective than graphitic carbon nitride, g-G3N4, and grapheme oxide, GO.

Aqueous-phase hydrodechlorination of trichloroethylene over Pd-based swellable organically-modified silica (SOMS): Catalyst deactivation due to chloride anions

Swellable-organically modified silica (SOMS) has been demonstrated to be an efficient catalyst scaffold for catalytic treatment of water contaminated with trichloroethylene (TCE). In this study, deactivation characteristics of Pd-incorporated SOMS for aqueous-phase hydrodechlorination (HDC) of TCE were investigated. Pd/SOMS catalysts were exposed to highly-concentrated chloride solutions (up to 1 M NaCl or 0.01 M HCl) to examine the deactivation resistant behavior of Pd/SOMS. The commonly used HDC catalyst Pd/Al2O3 was also studied for comparison purposes. Pd/SOMS and Pd/Al2O3 in their pristine and treated states were tested for aqueous-phase HDC of TCE and characterized by several techniques including N2 physisorption, inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray photoelectron spectroscopy, extended X-ray absorption fine structure spectroscopy (EXAFS), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of adsorbed CO. The aqueous-phase treatments had a pronounced adverse effect on the textural properties of Pd/Al2O3, although the effect was independent of the type of the chloride precursor, NaCl or HCl. Treating Pd/Al2O3 with chloride-containing solutions lowered the catalytic activity due to formation of Pd-Cl complexes and active metal leaching. The leached Pd obtained from the treatment solution was shown to be inactive for aqueous-phase HDC of TCE. While Pd/Al2O3 underwent severe deactivation due to the chloride treatments, Pd/SOMS exhibited resistance to chloride deactivation and metal leaching. The chloride treatments did not impact the textural properties of Pd/SOMS. The achieved deactivation resistance was attributed to the novel characteristics of the SOMS support.

Ionic liquid decorated chitosan hybridized with clay: A novel support for immobilizing Pd nanoparticles

Taking advantage of biocompatible chitosan (CS), halloysite (Hal) and ionic liquid (IL), a triple hybrid system, Hal-CS-SFIL was designed and prepared via covalent bonding of Cl-functionalized Hal and CS-SFIL. The hybrid system was successfully utilized as a heterogeneous catalyst support for immobilizing Pd nanoparticles. The resulting hybrid catalyst, Pd@Hal-CS-SFIL was used as a heterogeneous catalyst for catalyzing Sonogashira reaction under mild reaction condition. The results showed that this catalyst was efficient. Studying the recyclability of the catalyst confirmed that the catalyst could be recycled for seven reaction runs with slight loss of the catalytic activity and Pd leaching. The role of each hybrid component in the catalysis was confirmed by comparing the catalytic activity of Pd@Hal, Pd@CS, Pd@Hal-CS and Pd@Hal-CS-SFIL. Moreover, the synergism between the components was established by observing the superior catalytic activity of the catalyst with those of Pd@Hal-CS + SFIL, Pd@CS-SFIL+Hal and Pd@Hal + CS-SFIL.

Pd immobilized on dendrimer decorated halloysite clay: Computational and experimental study on the effect of dendrimer generation, Pd valance and incorporation of terminal functionality on the catalytic activity

Dendrimer (PAMAM) decorated halloysite nanoclay (Hal) was prepared and applied for immobilization of Pd catalytic species to develop an efficient catalyst for copper and ligand-free CC coupling reactions. The effect of dendrimer generation, Pd valance and incorporation of anthranilamide as terminal functionality of dendrimer on the catalytic activity of the hybrid catalyst was studied experimentally and theoretically. The results of DFT computational studies on the effect of Pd valence showed that Pd(0) has much higher binding energy (−44.3 kcal/mol) on the modified halloysite surface, exposing PAMAM group, than Pd(OAc)2 with the binding energy of only −14.3 kcal/mol. Hence, Pd(0) was selected for experimental investigations. Again, computational studies on the two dendrimer generations, I and II, revealed higher stability of Pd(0) impregnated on Hal-PAMAM in generation I (G1) than it in G2. These results were experimentally confirmed by the synthesis of both Pd@Hal-PAMAM-G1 and Pd@Hal-PAMAM-G2 and comparing their catalytic activities for promoting the model coupling reactions. Additionally, the effect of terminal groups of dendrimer periphery was studied by comparing the catalytic activity of the catalysts with amine and anthranilamide terminated dendrimer, Pd@Hal-PAMAM-G1-ISA and Pd@Hal-PAMAM-G1. Interestingly, the experimental results were in good agreement with the theoretical findings and established Pd@Hal-PAMAM-G1-ISA as the catalyst of the choice. It was found that Pd@Hal-PAMAM-G1-ISA could promote both Sonogashira and Heck C-C coupling reactions efficiently in aqueous media (1:1 mixture of H2O and EtOH) and could be successfully recovered and reused for 10 reaction times with slight loss of the catalytic activity and Pd leaching.

Biocompatible starch-halloysite hybrid: An efficient support for immobilizing Pd species and developing a heterogeneous catalyst for ligand and copper free coupling reactions

Combining the exceptional features of halloysite and starch, a unique hybrid was synthesized based on conjugation of amine-functionalized starch with Cl-halloysite nanoclay followed by coordination of Pd (II) acetate. The resultant hybrid catalyst, Pd@Hal-SA, was used as a heterogeneous catalyst for promoting copper and ligand-free coupling reactions under mild reaction condition. The catalyst exhibited high catalytic activity and recyclability (up to 10 reaction runs) with slight loss of the catalytic activity that stemmed from slight Pd leaching. The comparison of the catalytic activity of Pd-Hal, Pd-SA and Pd@Hal-SA confirmed the superior performance of the latter, indicating the contribution of two components, SA and Hal to the catalysis. Moreover, the catalytic activity of Pd@Hal-SA was higher than that of Pd@Hal + SA, implying that the use of hybrid system was more efficient that use of individual components in a separated form, due to the synergism between SA and Hal.

Synthesis of Pd/SiO2 Catalysts in Various HCl Concentrations for Selective NBR Hydrogenation: Effects of H+ and Cl- Concentrations and Electrostatic Interactions.

A series of silica supported Pd (Pd/SiO2) catalysts were prepared in various HCl concentrations (CHCl) of the impregnation solution with different electrostatic interactions between Pd precursor and support, and their catalytic properties were evaluated by the selective hydrogenation of nitrile butadiene rubber (NBR). The results show that with the CHCl increasing from 0.1 to 5 M, the particle size of Pd nanoparticles dramatically decreases from 24.2 to 5.1 nm and stabilizes at ∼5 nm when CHCl is higher than 2 M. Using the catalysts prepared with a high CHCl (>2 M), an excellent hydrogenation degree (HD) of ∼94% with 100% selectivity to C=C can be acquired under mild conditions. Interestingly, the HD could be remarkably increased from 65 to 92% by increasing only CCl– from 0.1 to 2 M with the addition of NaCl while keeping CH+ at 0.1 M. This is because PdCl42– is the predominant existing form of precursor at high CCl–, which has a strong electrostatic attraction with the positively charged support favorable for the formation of small-sized Pd nanoparticles over silica. Notably, Pd leaching behavior during the hydrogenation reaction is closely related to CH+, and the higher the CH+, the less Pd residues are detected in the hydrogenated NBR. Our contribution is to provide a facile strategy to synthesize effective and stable Pd/SiO2 catalysts via adjusting the electrostatic interaction, which exhibits a high activity and selectivity for NBR hydrogenation.

Palladium nanoparticles immobilized on cyclodextrin‐decorated halloysite nanotubes: Efficient heterogeneous catalyst for promoting copper‐ and ligand‐free Sonogashira reaction in water–ethanol mixture

Combining the excellent features of halloysite nanoclay and cyclodextrin, a novel hybrid system was designed and synthesized based on covalent attachment of tosylated cyclodextrin to thiosemicarbazide‐functionalized halloysite nanoclay and used for the immobilization of Pd nanoparticles. The resulting hybrid, Pd@HNTs‐T‐CD, was then characterized using various techniques, and successfully used for promoting copper‐ and ligand‐free Sonogashira coupling reactions of halobenzenes and acetylenes in a mixture of water and ethanol. Notably, under Pd@HNTs‐T‐CD catalysis, the reaction could proceed in relatively short reaction time to furnish the corresponding products in high yields. Additionally, the catalyst was recyclable and could be simply recovered and reused for several reaction runs. Results also established negligible leaching of Pd, indicating the efficiency of HNTs‐T‐CD for embedding Pd nanoparticles.

Pd@HNTs-CDNS-g-C3N4: A novel heterogeneous catalyst for promoting ligand and copper-free Sonogashira and Heck coupling reactions, benefits from halloysite and cyclodextrin chemistry and g-C3N4 contribution to suppress Pd leaching

For the first time, a ternary hybrid system composed of halloysite nanotubes, HNTs, cyclodextrin nanosponges, CDNS, and g-C3N4 is prepared and used for immobilization of Pd(0) nanoparticles and development of a heterogeneous catalyst, Pd@HNTs-CDNS-g-C3N4 for promoting ligand and copper-free Sonogashira and Heck coupling reactions in aqueous media. HNT as a porous tubular clay with outstanding thermal, mechanical and textural properties can act as a support for immobilizing Pd nanoparticles. The role of CDNS can be explained on the base of its capability to form inclusion complexe with substrates and bringing them in the vicinity of the catalytic active sites. Regarding the role of g-C3N4 in catalysis, it is proved that its presence can suppress the Pd leaching dramatically. The contribution of each component as well as synergistic effect between them results in high catalytic activity and recyclability (up to 10 reaction runs) of the catalyst.

Combination of carbon nanotube and cyclodextrin nanosponge chemistry to develop a heterogeneous Pd-based catalyst for ligand and copper free C-C coupling reactions

Carbon nanotubes and cyclodextrin nanosponge were hybridized and used as a support for embedding Pd(0) nanoparticles and developing a novel and heterogeneous catalyst, Pd@CDNS-CNT, for promoting ligand and copper-free Sonogashira and Heck coupling reactions in aqueous media and mild reaction condition. Cyclodextrin nanosponge could contribute to catalysis through encapsulating the reagents and transferring them in the vicinity of Pd nanoparticles. The results established that the catalytic activity of Pd@CDNS-CNT was superior to those of Pd@CNT, Pd@CDNS and Pd@CNT + CDNS, indicating the synergism between the components of the hybrid system. Notably, various aryl halides including aryl iodide, bromide and chloride were useful substrates for the coupling reactions and affording the corresponding products in high to excellent yields in short reaction times. Moreover, the catalyst was recyclable up to six reaction runs with negligible Pd leaching.

Palladium-scavenging self-assembled hybrid hydrogels - reusable highly-active green catalysts for Suzuki-Miyaura cross-coupling reactions.

A hybrid hydrogel based on 1,3:2,4-dibenzylidene sorbitol (DBS) modified with acyl hydrazides combined with agarose was used for in situ reduction and binding of palladium from aqueous mixtures without the need for an external reducing agent. Palladium uptake was monitored and the formation of Pd nanoparticles (PdNPs) trapped within the gel and located close to the nanofibres was confirmed. This gel effectively scavenges palladium from solution to concentrations < 0.04 ppm - well below the recommended limits for pharmaceutical products. The resulting hybrid hydrogel with embedded PdNPs was used as a catalyst for Suzuki-Miyaura cross-coupling reactions. The gel network stabilises PdNPs, preventing aggregation/leaching and giving excellent catalytic lifetimes. The gel acts as a simple reaction dosing form, being simply added to reactions performed in green solvents in air. Once reactions are complete, the gel can be simply removed, recycled and reused (>10 times). Reactions were purified by simple washing protocols, and leaching of Pd from the gels is limited (<1 ppm). The gels were also used in flow-through mode, giving efficient, rapid reactions, with easy work-up. These catalytic gels combine advantages of homogeneous and heterogeneous catalysts - they are solvent compatible with the reaction taking place in a solution-like environment, while the solid-like gel network enables catalyst recycling. In summary, these hydrogels scavenge 'waste' palladium and convert it into gel 'wealth' capable of efficient, environmentally-friendly Suzuki-Miyaura catalysis.