Supported Pd Catalysts Research Articles

Highly dispersed Pd nanoparticles for electrocatalytic dechlorination: Positive and negative effects of carbon supports

It is generally known that carbon supports with a large surface area are essential for dispersion of Pd catalysts and adsorption of pollutants (e.g., chlorinated compounds), thus enabling enhanced mass transfer and increased reaction kinetics. However, we demonstrate that, in spite of contributing to achieving highly dispersed Pd nanoparticles, a high-surface-area carbon support favoring fast adsorption of 2,4-dichlorophenol negatively impacts the catalytic activity of Pd. Comparisons of catalytic performance between Pd/activated carbon (AC) catalysts with different mass loadings in a 3D electrochemical dechlorination reactor suggested that Pd(60%)/AC outperformed Pd(10%)/AC, although the latter had smaller Pd catalysts and the amount of Pd was same in these experiments. We found that the dechlorination rate constant was inversely correlated to the adsorption rate constant at Pd loadings from 10% to 60%. We further verified that the use of C3N4, an optimal carbon support with low surface area that allows good dispersion of Pd nanoparticles (10%), is critical in accelerating the dechlorination reaction kinetics due to the improved accessibility of active sites to the pollutants. This study provides information on how to select optimal supporting materials with desirable features that avoid catalyst aggregation and pre-adsorption of pollutants when the supported Pd catalysts are used as the moveable particle electrodes.

Maximizing the synergistic effect of PdAu catalysts on TiO2(1 0 1) for robust CO2 reduction: A DFT study

To provide insight into how to realize maximization of the synergistic effect of supported PdAu catalysts, we have performed first-principles calculations for CO2 reduction over PdAu/TiO2(1 0 1). The results indicate that introducing a secondary metal (Au) to supported Pd catalyst and controlling Au concentration can affect the binding energy of reactants and also alter the dominant reaction pathway. The energetically preferred path for CO2 reduction on Pd8-xAux/TiO2 changes from the formate pathway (referred to as the “CO2 HYD” pathway) (x = 0–3) to the reverse water-gas shift and CO hydrogenation (“RWGS + CO HYD”) pathway (x = 4–6). Notably, the CO2 reduction activity shows a volcano trend as a function of the binding energy of the initial reactant CO2* in the “CO2 HYD” pathway or the adsorption energy difference between CHO* and CO* in the “RWGS + CO HYD” pathway. In addition, there is a component-dependent relationship between the water-promotion-effect and the nanoalloy structure. This work proposes fundamental insights into the effect of nanoalloy composition and water promotion in maximizing the synergy of PdAu catalysts for CO2 reduction, providing facile descriptors for the activity of reaction pathways, and offering important guidance for rational design of supported nanoalloy catalysts.

Deep Hydrogenation Saturation of Naphthalene Facilitated by Enhanced Adsorption of the Reactants on Micro‐Mesoporous Pd/HY

AbstractDeep hydrogenation saturation of polycyclic aromatic hydrocarbons is of great importance for the production of valuable chemical products, but is hard due to the presence of hardly broken π bond. In this work, micro‐mesoporous HY supported Pd catalysts (Pd/HY‐a) have been prepared by a simple impregnation method following alkali treatment of pristine HY zeolite, which exhibited superior performance for the deep hydrogenation saturation of naphthalene. Pd/HY‐a was systematically characterized and compared with the Pd catalysts supported on pristine HY, ZSM‐5, SBA‐15, and Al2O3. In Pd/HY‐a, abundant mesoporous pore channels together with suitable B acid sites greatly facilitate the adsorption of the reactants (naphthalene and tetralin) and properly tune the electron state of loaded Pd. Therefore, efficient deep hydrogenation saturation of naphthalene has been achieved on Pd/HY‐a. Moreover, the kinetic behaviors of naphthalene hydrogenation on Pd/HY‐a were preliminarily investigated, in which the first‐order kinetic model fitted the experimental data well in the early reaction stage.

Preparation of Pd/SiO2 Catalysts by a Simple Dry Ball-Milling Method for Lean Methane Oxidation and Probe of the State of Active Pd Species

A series of Pd/SiO2 catalysts were prepared with different Pd precursors by a dry ball-milling method and used in the catalytic oxidation of lean methane at low temperature. The effect of Pd precursors on the catalytic performance was investigated and the state of the most active Pd species was probed. The results indicate that dry ball-milling is a simple but rather effective method to prepare the Pd/SiO2 catalysts for lean methane oxidation, and palladium acetylacetonate is an ideal precursor to obtain a highly active Pd/SiO2-Acac catalyst with well- and stably dispersed Pd species, owing to the tight contact between acetylacetonate and Si–OH on the SiO2 support. Besides the size and dispersion of Pd particles, the oxidation state of Pd species also plays a crucial role in determining the catalytic activity of Pd/SiO2 in lean methane oxidation at low temperature. A non-monotonic dependence of the catalytic activity on the Pd oxidation state is observed. The activity of various Pd species follows the order of PdOx >> Pd > PdO; the PdOx/SiO2-Acac catalysts (in particular for PdO0.82/SiO2-Acac when x = 0.82) exhibit much higher activity in lean methane oxidation at low temperature than Pd/SiO2-Acac and PdO/SiO2-Acac. The catalytic activity of PdOx/SiO2 may degrade during the methane oxidation due to the gradual transformation of PdOx to PdO in the oxygen-rich ambiance; however, such degradation is reversible and the activity of a degraded Pd/SiO2 catalyst can be recovered through a redox treatment to regain the PdOx species. This work helps to foster a better understanding of the relationship between the structure and performance of supported Pd catalysts by clarifying the state of active Pd species, which should be beneficial to the design of an active catalyst in lean methane oxidation at low temperature.

Si-doped Al2O3 nanosheet supported Pd for catalytic combustion of propane: effects of Si doping on morphology, thermal stability, and water resistance.

Catalytic combustion of propane as typical light alkanes was important for the purification of industrial VOCs and automobile hydrocarbon emissions. Si-doped Al2O3 nanosheet was synthesized by a hydrothermal method, and effects of Si content on the morphology and thermal stability of Al2O3 were investigated. The doping of SiO2 could tune the thickness of Al2O3 nanosheets and significantly improve its thermal stability, the θ phase was still maintained, and the specific surface area was as high as 56.3 m2 g-1 after calcination at 1200 °C. And then the Si-doped Al2O3 nanosheets were used as support of Pd catalysts (Pd/Si-Al2O3 nanosheets) for catalytic combustion of propane, especially Pd/3.6Si-Al2O3 nanosheets, which presented high activity, stability, and resistance to sintering and H2O due to the promotion of Si on the thermal stability of Al2O3 and the stabilization (dispersion, isolation, and strong interaction) of PdOx species.

Porous Polyurea Supported Pd Catalyst: Easy Preparation, Full Characterization, and High Activity and Reusability in Reduction of Hexavalent Chromium in Aqueous System

Porous Polyurea Supported Pd Catalyst: Easy Preparation, Full Characterization, and High Activity and Reusability in Reduction of Hexavalent Chromium in Aqueous System

Influence of NOx on the activity of Pd/θ-Al2O3 catalyst for methane oxidation: Alleviation of transient deactivation

Alumina supported Pd catalyst (Pd/Al2O3) is active for complete oxidation of methane, while often suffers transient deactivation during the cold down process. Herein, heating and cooling cycle tests between 200 and 900°C and isothermal experiments at 650°C were conducted to investigate the influence of NOx on transient deactivation of Pd/θ-Al2O3 catalyst during the methane oxidation. It was found that the co-fed of NO alleviated transient deactivation in the cooling ramp from 800 to 500°C, which was resulted from the in situ formation of NO2 during the process of methane oxidation. Over the Pd/θ-Al2O3, thermogravimetric analysis and O2 temperature programmed oxidation measurements confirmed that transient deactivation was due to the decomposition of PdO particles and the hysteresis of Pd reoxidation, while the metal Pd entities were less active for methane oxidation than the PdO ones. CO pulse chemisorption and scanning transmission electron microscopy characterizations rule out the NO2 effect on Pd size change. Powder X-ray diffraction and X-ray photoelectron spectroscopy characterizations were used to obtain palladium status of Pd/θ-Al2O3 before and after reactions, indicating that in lean conditions at 650°C, the presence of NO2 increases the content of active PdO on the catalyst surface, thus benefits methane oxidation. Homogeneous reaction between CH4, O2, and NOx may be partially responsible for the alleviation above 650°C. The interesting research of alleviation in transient deactivation by NOx, the components co-existing in exhausts, are of great significance for the application.

LDH derived MgAl2O4 spinel supported Pd catalyst for the low-temperature methane combustion: Roles of interaction between spinel and PdO

Poor catalytic activity and stability are primary defects of traditional Pd/Al2O3 catalysts for the low-temperature methane combustion. Herein, we developed a facile way to synthesize a MgAl-LDHs derived MgAl2O4 spinel with good crystalline lattice and high surface area, which was used as support of Pd-based catalysts. Catalysts with Mg/Al ratio of 1/3 presented the highest methane combustion activity. It was found the well-crystallized MgAl2O4 spinel promoted the dispersion and crystallization of PdO due to the strong interaction between PdO and support, and the electrophilicity and basicity originated from Mg doping suppressed the sintering of PdO particles, leading to the excellent performance of Pd/MgAl3. Moreover, these factors also inhibited the formation of surface OH- species, therefore, improved the water resistance. Such a synthesis strategy of the Pd/MgxAly derived from LDHs and the roles of MgAl2O4 spinel could pose some meaningful directions for developing high-efficient Pd-based catalysts for the low-temperature methane combustion.

Synthesis of yolk-shell magnetic porous organic nanospheres supported Pd catalyst for oxidation of alcohols and Heck reactions

Yolk-shell magnetic porous organic nanospheres (MPONs) supported Pd nanoparticles (Pd@MPONs) were synthesized by encapsulating Fe3O4 and Pd nanoparticles in one cavity of hollow porous organic nanospheres (HPONs) using a continuous “ship-in-bottle” strategy. The obtained Pd@MPONs possessed a hierarchically micro/mesoporous structure, high surface area (354 m2/g) and displayed excellent magnetic response (9 emu/g). They showed high catalytic performance in the oxidation of alcohols under mild conditions and the Heck-Mizoroki reaction, and brilliant magnetic recyclability, they can be removed rapidly from a reaction system using external magnetic fields without any catalytic activity decrease. Hence, the Pd@MPONs are easily recoverable nanocatalysts which have practical significance in the future sustainable industry.

Facile Redox Synthesis of Novel Bimetallic Crn+/Pd0 Nanoparticles Supported on SiO2 and TiO2 for Catalytic Selective Hydrogenation with Molecular Hydrogen

The bimetallic Crn+/Pd0 nanoparticles have been synthesized for the first time by a two-step redox method. The method includes the deposition of Pd0 nanoparticles on the surface of SiO2 and TiO2 carriers followed by the deposition of Crn+ on the surface of Pd0 nanoparticles using the redox procedures, which are based on the catalytic reduction of Crn+ with H2 in aqueous suspensions at ambient conditions. Transmission (TEM) and scanning (SEM) electron microscopy, X-ray photoelectron spectroscopy (XPS), Fourie-transformed infrared spectroscopy of adsorbed CO (FTIR-CO), and CO chemisorption studies were performed to characterize the morphology, nanoparticle size, element, and particle distribution, as well as the electronic state of deposited metals in the obtained catalysts. A decrease in nanoparticle size from 22 nm (Pd/SiO2) to 2–6 nm (Pd/TiO2) makes possible deposition of up to 1.1 wt.% Cr most likely as Cr3+. The deposition of CrOx species on the surface of Pd nanoparticles was confirmed using FTIR of adsorbed CO and the method of temperature-programmed reduction with hydrogen (TPR-H2). The intensive hydrogen consumption in the temperature ranges from −50 °C to 40 °C (Cr/Pd/SiO2) and from −90 °C to −40 °C (Cr/Pd/TiO2) was first observed for the supported Pd catalysts. The decrease in the temperature of β-PdHx decomposition indicates the strong interaction between the deposited Crn+ species and Pd0 nanoparticle after reduction with H2 at 500 °C. The novel Crn+/Pd/TiO2 catalysts demonstrated a considerably higher activity in selective hydrogenation of phenylacetylene than the Pd/TiO2 catalyst at ambient conditions.

Tailoring a Dynamic Metal-Polymer Interaction to Improve Catalyst Selectivity and Longevity in Hydrogenation.

Controlling metal-support interactions is important for tuning the catalytic properties of supported metal catalysts. Here, premade Pd particles are supported on stable polymers containing different ligating functionalities to control the metal-polymer interactions and their catalytic properties in industrially relevant acetylene partial hydrogenation. The polymers containing strongly ligating groups (e.g., Ar-SH and Ar-S-Ar) can form a polymer overlayer on the Pd surface, which enables selective acetylene adsorption and partial hydrogenation to ethylene without deactivation. In contrast, polymers with weakly ligating groups (e.g., Ar-O-Ar) do not form an overlayer, resulting in non-selective hydrogenation and fast deactivation, similar to Pd catalysts on conventional inorganic supports. The results imply that tuning the metal-polymer interactions via rational polymer design can provide an efficient way of synthesizing selective and stable catalysts for hydrogenation.

Pd/SiO2 as an active and durable CH4 oxidation catalyst for vehicle applications

The removal of CH4 is critical to address environmental concerns for developing natural gas vehicles (NGVs), because CH4 has a 20-fold-greater contribution to the greenhouse effect than CO2. Alumina supported Pd catalysts are widely used for CH4 oxidation due to their superior catalytic activity and durability compared to other CH4 oxidation catalysts. However, the continuous deactivation of Pd-based catalysts during vehicle applications needs further development of active and durable catalysts. Here, we report that Pd/SiO2 can be active and durable catalysts for CH4 oxidation in practically relevant condition via a simple reductive regeneration. CH4 oxidation light-off curves of freshly prepared Pd/SiO2 (air, 550°C) present higher activity than those of Pd/Al2O3, but severe deactivation was observed after hydrothermal aging (HTA, air with 10% H2O) at 850°C. However, X-ray diffraction (XRD), scanning transmission electron microscopy (STEM) and volumetric CO adsorption suggest that Pd/SiO2 has similar particle sizes as Pd/Al2O3 even after HTA, indicating that Pd/PdO particle sintering is not the origin of the deactivation of Pd/SiO2. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) shows that the CO was not adsorbed on Pd/SiO2 after HTA, whereas it was adsorbed on Pd/Al2O3 after HTA. These results demonstrate that the deactivation of Pd/SiO2 originates mainly from the blockage of the Pd/PdO surface by the SiO2 overlayer formed during HTA. The Pd/PdO surfaces are re-exposed by a simple H2 treatment at 500°C, resulting in CO adsorption on the Pd/PdO surface and regeneration for CH4 oxidation activity, which suggests that the Pd/PdO surface was re-exposed by a reduction treatment. This work also demonstrates that SiO2-supported Pd catalysts can be a good candidate for active and durable CH4 oxidation catalysts by using the proper regeneration protocols.

Understanding the three-way catalytic reaction on Pd/CeO2 by tuning the chemical state of Pd

To investigate the correlation of activity and chemical state of Pd species in the three-way catalytic reaction, the supported Pd catalysts were prepared by using CeO2 calcined at different temperatures as supports. It turned out that the chemical state of Pd could severely affect the catalytic activity of Pd/CeO2, which depended on the CeO2 properties and the interaction between Pd and CeO2. With increasing CeO2 calcination temperature from 500 to 1200 °C, the state of Pd gradually transferred from Pd4+ as PdxCe1-xO2-σ to Pd2+ as PdO due to the decreased interaction between Pd and CeO2. Meanwhile, the TOFs of C3H8 oxidation linearly increased and the TOFs of CO oxidation showed a reversed trend, demonstrating the active states of Pd in C3H8 and CO oxidation were different. NO conversion was correlated to the activity of CO oxidation in low-temperature zone and C3H8 oxidation in high-temperature zone during the three-way catalytic reaction. Among them, Pd/CeO2(500) showed the highest CO oxidation activity and low-temperature NO conversion due to the enhanced adsorption ability of CO and NO. The existence of PdO on the surface of high-temperature calcined CeO2 facilitated C3H8 activation and reaction with surface nitrate/nitrite, which promoted NO conversion in high temperature.

Methane oxidation over supported Pd catalysts prepared by magnetron sputtering

Abstract While magnetron sputtering has been used to deposit metals onto a range of solid substrates, its application to produce porous heterogeneous catalysts in powder form is relatively unstudied. Here, magnetron sputtered Pd heterogeneous catalyst powders were prepared using a shaker operated at optimal experimental settings to give uniform coverage of the powders, and tested in the abatement of exhaust emissions in natural gas fuelled engines via the oxidation of methane. Pd nanoparticles were deposited onto alumina, titania and zeolite supports, in powder form. X-ray diffraction confirmed that the characteristic structure of each support was maintained following sputtering. The quantity of Pd increased (a) with deposition time and (b) as a function of support in the order alumina

Promoting NOx reduction via in situ activation of perovskite supported Pd catalysts under alternating lean-burn/fuel-rich operating atmospheres

Herein, we report the excellent De-NOx performance of La0.7Sr0.3MnO3 (LSM) perovskite-supported Pd catalysts (Pd-LSM) in alternating lean-burn/fuel-rich atmospheres using C3H6 as reductant and describe the in situ activation of the Pd catalysts via metal-support interaction (MSI) tuning. The NOx reduction conversion of the Pd-LSM catalyst increased significantly from 56.1% to 90.1% and the production of N2O was suppressed. Our results demonstrated that this behavior was mainly attributed to the in situ transformation of Pd2+ into Pd0 during the reaction. The generated Pd0 species could readily activate the C3H6 reductant and achieve an eight-fold higher turnover frequency than Pd2+ for the reduction of NOx. Moreover, excessive MSIs inhibited the in situ generation of Pd0, and thereby, lowered the De-NOx activity of the catalyst even at high Pd dispersion. In addition, the Pd-LSM catalysts exhibited much higher S tolerance than conventional Al2O3-supported catalysts. Our study provides a new approach for analyzing and designing highly active metal catalysts operated under dynamic alternating oxidizing/reducing atmospheric conditions.

Fabrication of PdZn alloy catalysts supported on ZnFe composite oxide for CO2 hydrogenation to methanol

The conversion of CO2 to methanol is of great significance for providing a means of CO2 fixation and the development of future fuels. Supported Pd catalysts have been demonstrated to be active for CO2 hydrogenation to methanol and PdZn alloy plays a key role in this reaction. Therefore, using ZnO-enriched support to increase the amount of nanometric PdZn alloy particles on the surface is an effective strategy to develop ideal catalysts. Herein, we fabricated a PdZn alloy catalyst supported on ZnO-enriched ZnFe2O4 spinel for efficient CO2 hydrogenation to methanol. The amount of formed PdZn alloy and catalyst structure influenced by ZnO concentration on ZnFe2O4 were explored to obtain the best Pd-Z1FO catalyst, which achieves a methanol space-time yield (STY) of 593 gkgcat−1h−1 (12 ggPd−1h−1) with CO2 conversion of 14% under reaction conditions of 290 °C, 4.5 MPa and 21600 mLg−1h−1. Furthermore, the amount of exposed PdZn alloy sites were measured by using CO-pulse chemisorption and we find a linearity between methanol production rate and PdZn alloy sites.

Selective hydrogenation of ethyne with highly-dispersed sub-2 nm Pd nanoparticles in a hemicellulosic gel-based microreaction chamber

Ethyne is often an unwanted impurity in ethene streams used in plastics industry. Supported Pd catalysts offer high ethyne conversion, but poor ethene selectivity due to over-hydrogenation which leads to the formation of carbonaceous deposits. In this paper, acrylamide was grafted by free radical polymerization onto bagasse pith hemicellulose (to form HEMI-g-AAMs), which was then used as a porous bio-based carrier of Pd nanoparticles. The obtained Pd/HEMI-g-AAMs catalyst showed an ethyne conversion and ethene selectivity of 100% and 94.70%, respectively, at 100 °C and a space velocity of 70,000 h−1. The nitrogen-rich bio-based support regulated the physicochemical properties and catalytic activity of the supported Pd nanoparticles. Results guide the development of new and improved Pd-based catalysts for the partial catalytic hydrogenation of ethyne to ethene.

Reaction pathways for the HDO of guaiacol over supported Pd catalysts: Effect of support type in the deoxygenation of hydroxyl and methoxy groups

The effect of support type (SiO2, CeO2, ZrO2, TiO2, Nb2O5) on the removal of the different oxygenated functional groups (hydroxyl and methoxy) was investigated in the hydrodeoxygenation (HDO) of guaiacol over supported Pd catalysts at 573 K and atmospheric pressure. The product distribution depended on the support type, and three main reaction pathways were proposed: demethoxylation, demethylation and dehydroxylation. Demethoxylation yielding phenol was the dominant reaction pathway over all catalysts with only a minor contribution from the demethylation reaction taking place. However, significant dehydroxylation reaction was still observed for the catalysts having Pd supported on ZrO2, TiO2 and Nb2O5. Further conversion of phenol to cylohexanone was favored over SiO2 and CeO2-based catalysts, while benzene was only detected over ZrO2, TiO2 and Nb2O5, which is due to the presence of oxophilic cations. DRIFTS measurements were carried out to evaluate the adsorption mode and strength of guaiacol on the catalyst surface. The functional groups involved in adsorption of guaiacol included both hydroxyl and methoxy groups. At the reaction conditions, the hydroxyl group is strongly adsorbed to the catalyst surface and may block the catalytic sites, thus inhibiting further conversion of phenol and resulting in lower deoxygenation rates.

Performance of carbon-modified Pd/SBA-15 catalyst for 2-ethylanthraquinone hydrogenation

Abstract Silica SBA-15 without removal of template P123 was calcined in an inert atmosphere and the carbon-modified SBA-15 thus obtained was used as the support of Pd catalyst for the hydrogenation of 2-ethylanthraquinone (EAQ). The effects of extraction times of P123 in SBA-15 with water prior to inert calcination and calcination temperature on the structure and catalytic performance of Pd catalyst were studied. The results of elemental analysis, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma, Fourier transform infrared spectroscopy, Raman spectra, water contact angle measurement, N2 adsorption-desorption, transmission electron microscopy and energy dispersive X-ray mapping showed that carbon content of catalysts varied in the range of 3.4 % and 1.1 % with increasing extraction times from 0 to 6 due to the decrease in the residual amount of P123 in uncalcined SBA-15. With rising calcination temperature, the occurrence state of carbon in catalysts was converted from amorphism into graphite. The Pd catalyst supported on SBA-15 extracted for 3 times and calcined at 650 °C had 2.0 % carbon, and exhibited the highest activity (0.37 molH2·gPd−1·min−1) and selectivity (98.9 %). This is due to the presence of appropriate amount of carbon, which provided a relatively high hydrophobicity without significantly reducing the specific surface area and pore size of SBA-15 support. The high hydrophobicity benefits the adsorption of EAQ from the working solution to the surface of catalyst.

Simultaneous utilization of electro-generated O2 and H2 for H2O2 production: An upgrade of the Pd-catalytic electro-Fenton process for pollutants degradation

• Pd/Activated carbon/stainless steel mesh (PACSS) hybrid cathode was fabricated. • H 2 and O 2 from water electrolysis were both utilized by PACSS cathode for H 2 O 2 generation. • PACSS cathode can support effective H 2 O 2 generation and activation simultaneously. • The novel process is more effective for pollutants degradation than Pd-catalytic EF process. The Electro-Fenton (EF) process is one of the promising advanced oxidation processes (AOPs) for environmental remediation. The H 2 O 2 yield of EF process largely determines its performance on organic pollutants degradation. Conventional Pd-catalytic EF process generates H 2 O 2 via the combination reaction of anodic O 2 and cathodic H 2 . However, the relatively expensive catalyst limits its application. Herein, a hybrid Pd/activated carbon (Pd/AC)-stainless steel mesh (SS) cathode (PACSS) was proposed, which enables more efficient H 2 O 2 generation. It utilizes AC, the support of Pd catalyst, as part of cathode for H 2 O 2 generation via 2-electron anodic O 2 reduction, and SS serve as a current distributor. Moreover, H 2 O 2 could be catalytically decomposed upon AC to generate highly reactive OH, which avoids the use of Fe 2+ . Compared with conventional Pd catalyst, H 2 O 2 concentration obtained by PACSS cathode is 248.2% higher, the O 2 utilization efficiency was also increased from 3.2% to 10.8%. Within 50 min, 26.3%, 72.5%, and 94.0% H 2 O 2 was decomposed by Pd, AC, and Pd/AC. Fluorescence detection results implied that Pd/AC is effective upon H 2 O 2 activation for OH generation. Finally, iron-free EF process enabled by PACSS cathode was examined to be effective for reactive blue 19 (RB19) degradation. After continuous running for 10 cycles (500 min), the PACSS cathode was still stable for H 2 O 2 generation, H 2 O 2 activation, and RB19 degradation, showing its potential application for organic pollutants degradation without increase in the running cost.