Durable Catalysts Research Articles

Lignin-assisted electronic modulation on NiSe/FeOx heterointerface for boosting electrocatalytic oxygen evolution reaction

The development of productive and durable non-precious metal catalysts for the sluggish oxygen evolution reaction (OER) is critical for water splitting. Herein, a novel NiSe-FeOx heterojunction encapsulated in lignin-derived carbon layer (NiSe-FeOx@LC) was synthesized via hydrothermal self-assembly and in-situ pyrolysis. NiSe-FeOx@LC exhibited excellent OER performance with an overpotential of 265 mV at 50 mA·cm−2, a Tafel slope of 83 mV·dec−1, as well as long-term stability. Both experimental and DFT calculation results indicated that the doping of FeOx into NiSe@LC successfully optimized the dual interface structure between NiSe and FeOx, thereby promoted the d-bands orbital hybridization, that facilitated electron transfer. Besides, the carbon coating effectively protected the NiSe-FeOx components from leaching and agglomerating during the reaction. This study provides insight into the significance of lignin-derived carbon-encapsulated metallic catalyst for electrocatalytic OER process.

Sustainable photoelectrocatalytic oxidation of antibiotics using Ag–CoFe2O4@TiO2 heteronanostructures for eco-friendly wastewater remediation

Developing high-performance and durable catalysts presents a significant challenge for oxidizing toxic inorganic and pharmaceutical compounds in wastewater. Recently, there has been a surge in the development of new heterogeneous catalysts for degrading pharmaceutical compounds, driven by advancements in electrocatalysts and photoelectrocatalysts. In this study, a plasmonic Ag nanoparticles decorated CoFe2O4@TiO2 heteronanostructures have been successfully designed to fabricate a high-performing photoelectrode for the oxidation of pharmaceutical compounds. The developed Ag–CoFe2O4@TiO2 possessed a higher electrochemical stability and effectively harvested the UV to visible and NIR radiation in sunlight which generates the enormous photochemical reactive species that involved in the oxidation of ibuprofen in wastewater. Under direct sunlight irradiation, Ag–CoFe2O4@TiO2 achieved complete oxidation of ibuprofen in wastewater at 0.8 V vs RHE. This indicates that metallic Ag nanoparticles are involved in the charge separation and transport of charge carriers from the photoactive sites of CoFe2O4@TiO2, promoting the generation of abundant hydroxy, oxy, and superoxide radicals that actively break the bonds of ibuprofen. Additionally, oxidation agents such as urea and H2O2 were utilized to enhance the formation of superoxide ions and hydroxyl radicals, which rapidly participate in the oxidation of ibuprofen. Significantly, testing for recyclability confirmed the stability of the Ag–CoFe2O4@TiO2 photoanode, ensuring its suitability for prolonged use in photoelectrochemical advanced oxidation processes. Integrating Ag–CoFe2O4@TiO2 photoanodes into water purification systems could enhance economic feasibility, reduce energy consumption, and improve efficiency.

Pt3Sn0.5Mn0.5 Intermetallic Electrocatalyst with Superior Stability for CO-Resilient Methanol Oxidation.

The sluggish kinetics of methanol oxidation reaction (MOR) and poor long-term durability of catalysts are the main restrictions of the large-scale applications of direct methanol fuel cells (DMFCs). Herein, we demonstrated an inspirational ternary Pt3Sn0.5Mn0.5/DMC intermetallic catalyst that reached 4.78 mA cm-2 and 2.39 A mg-1Pt for methanol oxidation, which were 2.50/2.44 and 5.62/5.31 times that of commercial PtRu/C and Pt/C. After the durability test, Pt3Sn0.5Mn0.5/DMC presented a very low current density attenuation (38.5%), which was significantly lower than those for commercial PtRu/C catalyst (84.2%) and Pt/C (93.1%). Density functional theory (DFT) calculations revealed that the coregulation of Sn and Mn altered the surface electronic structure and endowed Pt3Sn0.5Mn0.5 with selective adsorption of Pt for CO and Sn for OH, which optimized the adsorption strength for intermediates and improved the reaction kinetics of MOR. Beyond offering an advanced electrocatalyst, this study provided a new point of view for the rational design of superior methanol oxidation catalysts for DMFC.

Synthesis of 3,4-dihydropyrimidines and octahydroquinazolinones by SBA-15 supported schiff-base iron (III) complex as durable and reusable catalyst under ultrasound irradiation

Biginelli-type heterocyclic compounds are particularly important due to their several chemical reactivities and various range of pharmacological activity. Therefore Biginelli reaction has witnessed several modification and numerous investigations are continuing in this field to develop more effective and efficient methodologies. In this research, Iron (III) schiff base immobilized SBA-15 has been prepared as a valuable, efficient, and recoverable catalyst for the Biginelli reaction. The morphology of the prepared catalyst was identified by spectroscopic characterization techniques and structural microscopic analysis including Fourier transform infrared (FT-IR) patterns, X-ray diffraction (XRD) by powder crystal method, Energy-dispersive X-ray spectroscopy (EDS) study, Thermogravimetric-Differential thermal analysis (TGA-DTA), Transmission electron microscopy (TEM) and Field emission scanning electron microscopy (FE-SEM) images. Biginelli compounds containing 3,4-dihydropyrimidines and octahydroquinazolinones were conveniently synthesized by this catalyzed protocol from the cycloaddition of aromatic aldehydes with the 1,3-dicarbonyl substrates and urea via ultrasonic waves. The several advantages of the presented approach are high yields and easy isolation of products, shorter reaction times, and milder conditions, structural stability and reusable catalyst. The combination of heterogeneous catalyst and ultrasonic radiation can make catalytic reactions more efficient than traditional ways attractive for academic researchers and application scholars in the industry.

Effect of Microporous Layer Cracks on Catalyst Durability of Polymer Electrolyte Fuel Cells for Heavy-Duty Applications

Effect of Microporous Layer Cracks on Catalyst Durability of Polymer Electrolyte Fuel Cells for Heavy-Duty Applications

Raney nickel induced interface modulation of active NiFe-hydroxide as efficient and robust electrocatalyst towards oxygen evolution reaction

Preparation of active and durable low-cost catalysts towards oxygen evolution reaction (OER) is essential for alkaline water splitting. Herein, porous Raney-Ni supported NiFe-LDH (NiFe-LDH/Raney-Ni) electrocatalyst was developed to achieve efficient and robust OER performance. Raney-Ni modulates the NiFe-LDH electronic structure by interfacial interaction. In-situ infrared shows the enhanced OH adsorption behavior, and in-situ Raman suggests that Raney-Ni promotes the formation of active NiFeOOH species on NiFe-LDH/Raney-Ni. Theoretical calculations found that the Fe atoms in NiFe-LDH/Raney-Ni enhances the charge transfer to the NiOOH species, which facilitates the formation of O* intermediates accelerating the OER process. The NiFe-LDH/Raney-Ni catalyst exhibits a low OER overpotential of 219 mV at 10 mA cm−2 in 1 M KOH with excellent stability for 200 h at 200 mA cm−2. Excellent performance is also achieved in alkaline electrolyzer test. This work presents a facile approach for the design of affordable and efficient alkaline OER electrocatalysts.

Growth of octahedral structured AgBiS2 single crystals and its insights on the high performance electrocatalytic hydrogen generation

Given the enormous depletion of fossil fuels and growing environmental concerns, there is an immediate need to develop alternative and clean energy sources. Hydrogen (H2), recognized for its cleanliness and renewability, is poised to meet future energy requirements. Consequently, ongoing research is focused on the development of electro-active, durable, and cost-effective catalysts to replace expensive noble metal-based electrocatalysts. In this study, microscale AgBiS2 chalcogenide derived from a single crystal is reported as promising electrocatalysts for the Hydrogen Evolution Reaction (HER) with a remarkably low overpotential. The physico-chemical characterization of the AgBiS2 catalyst has been investigated using various analytical techniques. The synthesized AgBiS2 catalyst exhibits excellent HER activity, manifesting a low overpotential of 86 mV at a current density of 10 mA cm−2 and a Tafel slope of 44 mV dec−1, along with superior stability even after 24 h in HER at a very high current density. The developed AgBiS2 also showcased stable production when subjected to a two-electrode system. The enhanced alkaline HER activity of AgBiS2 can be attributed to its phase purity, high crystallinity, and the presence of high active sites. The observed high electrochemical performance and stability position AgBiS2 as a potential electrocatalyst for the hydrogen evolution reaction. This finding holds significant promise in the quest for efficient, durable, and economically viable catalysts to drive the shift towards clean and renewable energy sources.

Toward Durable CO2 Electroreduction with Cu-Based Catalysts via Understanding Their Deactivation Modes.

The technology of CO2 electrochemical reduction (CO2ER) provides a means to convert CO2, a waste greenhouse gas, into value-added chemicals. Copper is the most studied element that is capable of catalyzing CO2ER to obtain multicarbon products, such as ethylene, ethanol, acetate, etc., at an appreciable rate. Under the operating condition of CO2ER, the catalytic performance of Cu decays because of several factors that alters the surface properties of Cu. In this review, these factors that cause the degradation of Cu-based CO2ER catalysts are categorized into generalized deactivation modes, that are applicable to all electrocatalytic systems. The fundamental principles of each deactivation mode and the associated effects of each on Cu-based catalysts are discussed in detail. Structure- and composition-activity relationship developed from recent in situ/operando characterization studies are presented as evidence of related deactivation modes in operation. With the aim to address these deactivation modes, catalyst design and reaction environment engineering rationales are suggested. Finally, perspectives and remarks built upon the recent advances in CO2ER are provided in attempts to improve the durability of CO2ER catalysts.

Tungsten oxide nanoparticles encapsulated by porous carbon for boosting H2S selective oxidation performance

Effective advancements for H2S removal are desperately expected to meet security and ecological necessities as natural guidelines on H2S emissions. Selective catalytic oxidation, as a green technology, has attracted attention owing to its direct conversion of H2S to S without thermodynamic constraints. Herein, we report a carbon-encapsulated WO3 (C@WO3–300) catalyst with nearly 100 % H2S conversion and 99 % S selectivity. Importantly, it likewise accomplishes noteworthy catalytic stability (over 120 h of continuous operation) and water resistance. Excellent durability may be attributed to the ideal porosity of C@WO3, which facilitates the adsorption and activation of H2S and O2. Additionally, the abundant lone pair electrons of carbon support can optimize the chemical environment of WO3-based catalysts and thereby benefit the O2 activation. This study provides a new avenue for the rational design of efficient and durable catalysts for continuous catalytic oxidative desulfurization.

In Situ Formation of Highly Durable Subnanometer Platinum Particle Electrocatalysts for Polymer Electrolyte Fuel Cells.

The durability of Pt nanoparticle catalysts is currently the most important factor limiting the widespread use of polymer electrolyte fuel cells (PEFCs). Specifically, the Pt nanoparticles in standard carbon black-supported Pt nanoparticle (Pt/CB) catalysts repeatedly aggregate on the CB surfaces during PEFC operation, thus, reducing the performance of the cell. Therefore, PEFCs must contain large quantities of Pt to maintain sufficient service lifetimes. This is the main factor hindering the reduction of the cost of PEFCs. The present research demonstrates that ultrafine Pt particles (Ptsubnanoes) having diameters of approximately 0.5 nm can be formed in situ from a platinum chloride complex (PtCl n ) on a carbon-based material doped with Fe and N via the dissolution and reprecipitation of Pt in the PtCl n during potential cycling in a 0.1 M HClO4 solution. The Ptsubnanoes are immobilized by both Fe and N in the support material. The mass-based catalytic activity of this material during the oxygen reduction reaction is eight times higher than that of a standard Pt/CB catalyst and is maintained even after 100,000 potential step cycles (0.6 ↔ 1.0 V). The present results provide guidelines for the development of highly durable yet active membrane electrode assemblies that minimize the use of Pt.

Recent Advances of PtCu Alloy in Electrocatalysis: Innovations and Applications

Developing highly active and durable platinum-based catalysts is crucial for electrochemical renewable energy conversion technologies but the limited supply and high cost of platinum have hindered their widespread implementation. The incorporation of non-noble metals, particularly copper, into Pt catalysts has been demonstrated as an effective solution to reduce Pt consumption while further promoting their performance, making them promising for various electrocatalytic reactions. This review summarizes the latest advances in PtCu-based alloy catalysts over the past several years from both synthetic and applied perspectives. In the synthesis section, the selection of support and reagents, synthesis routes, as well as post-treatment methods at high temperatures are reviewed. The application section focuses not only on newly proposed electrochemical reactions such as nitrogen-related reactions and O2 reduction but also extends to device-level applications. The discussion in this review aims to provide further insights and guidance for the development of PtCu electrocatalysts for practical applications.

Nickel Nanoplates Enclosed by (111) Facets as Durable Oxygen Evolution Catalysts in Anion Exchange Membrane Water Electrolyzers

AbstractThe long‐term stability of Ni‐based catalysts, employed in the anode of anion exchange membrane water electrolyzers (AEMWE), has been a persisting concern. In this work, through a simple and powerful electrochemical anodization process, vertically aligned β‐NiOOH atomic sheets (vertical‐β‐NiOOH) grown on Fe‐doped Ni nanoplates (FeNi nanoplates) as a solution are offered. This innovative electrocatalyst demonstrates sustained stability of constant current density for over 120 d during the oxygen evolution reaction.The zero‐gap AEMWE cell harnessing the anodized FeNi nanoplates achieves a remarkable current density of 2.26 A cm−2 at 1.80 V with an energetic efficiency of 85.1%. It is anticipated that the electrochemically produced highly active, stable Ni‐based nanostructures demonstrate the potential in pushing the boundaries of AEMWE technology.

Enhancing electrochemical water-splitting efficiency with superaerophobic nickel-coated catalysts on Chinese rice paper

The quest for efficient hydrogen production highlights the need for cost-effective and high-performance catalysts to enhance the electrochemical water-splitting process. A significant challenge in developing self-supporting catalysts lies in the high cost and complex modification of traditional substrates. In this study, we developed catalysts featuring superaerophobic microstructures engineered on microspherical nickel-coated Chinese rice paper (Ni-RP), chosen for its affordability and exceptional ductility. These catalysts, due to their microspherical morphology and textured surface, exhibited significant superaerophobic properties, substantially reducing bubble adhesion. The nickel oxy-hydroxide (NiOxHy) and phosphorus-doped nickel (PNi) catalysts on Ni-RP demonstrated effective roles in oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), achieving overpotentials of 250 mV at 20 mA cm−2 and 87 mV at −10 mA cm−2 in 1 M KOH, respectively. Moreover, a custom water-splitting cell using PNi/Ni-RP and NiOxHy/Ni-RP electrodes reached an impressive average voltage of 1.55 V at 10 mA cm−2, with stable performance over 100 h in 1 M KOH. Our findings present a cost-effective, sustainable, and easily modifiable substrate that utilizes superaerophobic structures to create efficient and durable catalysts for water splitting. This work serves as a compelling example of designing high-performance self-supporting catalysts for electrocatalytic applications.

Hydrogen‐Bond‐Enhanced Photoreforming of Biomass Furans over a Urea‐Incorporated Cu(II) Porphyrin Framework

AbstractSolar‐driven upgrading of biomass‐derived 5‐hydroxylmethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) holds great promise for sustainable production of bio‐plastics and resins. However, the process is limited by poor selectivity and sluggish kinetics due to the vertical coordination of HMF at relatively strong metal sites. Here, we purposely developed a Cu(II) porphyrin framework featuring side‐chain incorporated urea linkages, denoted as TBUPP−Cu MOF, to render HMF a weak hydrogen bond at the urea site and flat adsorption via π–π stacking with the benzene moiety. The unique configuration promotes the approaching of −CHO of HMF to the photoexcited porphyrin ring towards kinetically and thermodynamically favourable intermediate formation and subsequent desorption. The charge localisation and orbital energy alignment enable the selective activation of O2 over the porphyrin to generate ⋅O2− and 1O2 instead of highly oxidative H2O2 and ⋅OH via spin‐flip electron transfer, which drive the ambient oxidation of proximal −CHO. The effective utilisation of redox species and circumvented over‐oxidation facilitate a FDCA selectivity of >90 % with a high turnover number of 193 molHMF molCu−1. The facile purification of high‐purity FDCA and zero‐waste recycling of intermediates and durable catalyst feature TBUPP−Cu MOF a promising photo‐oxidation platform towards net‐zero biorefining and organic transformations.

Hydrogen-Bond-Enhanced Photoreforming of Biomass Furans over aUrea-Incorporated Cu(II) Porphyrin Framework.

Solar-driven upgrading of biomass-derived 5-hydroxylmethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) holds great promise for sustainable production of bio-plastics and resins. However, the process is limited by poor selectivity and sluggish kinetics due to the vertical coordination of HMF at relatively strong metal sites. Here, we purposely developed a Cu(II) porphyrin framework featuring side-chain incorporated urea linkages, denoted as TBUPP-Cu MOF, to render HMF a weak hydrogen bond at the urea site and flat adsorption via π-π stacking with the benzyl moiety. The unique configuration promotes the approaching of -CHO of HMF to the photoexcited porphyrin ring towards kinetically and thermodynamically favourable intermediate formation and subsequent desorption. The charge localization and orbital energy alignment enable the selective activation of O2 over the porphyrin to generate ·O2- and 1O2 instead of highly oxidative H2O2 and ·OH via spin-flip electron transfer, which drive the ambient oxidation of proximal -CHO. The effective utilisation of redox species and circumvented over-oxidation facilitate a FDCA selectivity of >90% with a high turnover number of 193 molHMF molCu-1. The facile purification of high-purity FDCA and zero-waste recycling of intermediates and durable catalyst feature TBUPP-Cu MOF a promising photo-oxidation platform towards net-zero biorefining and organic transformations.

Laser synthesis of nanoparticles in organic solvents - products, reactions, and perspectives.

Laser synthesis and processing of colloids (LSPC) is an established method for producing functional and durable nanomaterials and catalysts in virtually any liquid of choice. While the redox reactions during laser synthesis in water are fairly well understood, the corresponding reactions in organic liquids remain elusive, particularly because of the much greater complexity of carbon chemistry. To this end, this article first reviews the knowledge base of chemical reactions during LSPC and then deduces identifiable reaction pathways and mechanisms. This review also includes findings that are specific to the LSPC method variants laser ablation (LAL), fragmentation (LFL), melting (LML), and reduction (LRL) in organic liquids. A particular focus will be set on permanent gases, liquid hydrocarbons, and solid, carbonaceous species generated, including the formation of doped, compounded, and encapsulated nanoparticles. It will be shown how the choice of solvent, synthesis method, and laser parameters influence the nanostructure formation as well as the amount and chain length of the generated polyyne by-products. Finally, theoretical approaches to address the mechanisms of organic liquid decomposition and carbon shell formation are highlighted and discussed regarding current challenges and future perspectives of LSPC using organic liquids instead of water.

A Universal Electronic Structure Modulation Strategy: Is Strong Adsorption Always Correlated with High Catalysis?

Unveiling the inherent link between polysulfide adsorption and catalytic activity is key to achieving optimal performance in Lithium-sulfur (Li-S)batteries. Currentresearch on the sulfur reaction process mainly relies on the strong adsorption of catalysts to confine lithium polysulfides (LiPSs) to the cathode side, effectively suppressing the shuttle effect of polysulfides. However, is strong adsorption always correlated with high catalysis? The inherent relationship between adsorption and catalytic activity remains unclear, limiting the in-depth exploration and rational design of catalysts. Herein, the correlation between "d-band center-adsorption strength-catalytic activity" in porous carbon nanofiber catalysts embedded with different transition metals (M-PCNF-3, M=Fe, Co, Ni, Cu) is systematically investigated, combining the d-band center theory and the Sabatier principle. Theoretical calculations and experimental analysis results indicate that Co-PCNF-3 electrocatalyst with appropriate d-band center positions exhibits moderate adsorption capability and the highest catalytic conversion activity for LiPSs, validating the Sabatier relationship in Li-S battery electrocatalysts. These findings provide indispensable guidelines for the rational design of more durable cathode catalysts for Li-S batteries.

Toward Developing Superior Cu-Based Metal-Organic Framework-Derived Materials for Electrocatalytic Oxidation of Ethanol.

This project addresses the urgent need for efficient and cost-effective development of electrocatalysts for the ethanol oxidation reaction (EOR). This reaction offers promising renewable energy solutions but faces challenges due to the slow EOR kinetics, typically requiring costly noble metal catalysts. To overcome these limitations, this study focuses on developing CuZn-based EOR catalysts derived from metal-organic frameworks (MOFs), focusing on understanding the structure-performance relationship between pristine MOF-based electrocatalysts and their pyrolyzed counterparts. Herein, bimetallic MOF materials with varying Cu/Zn ratios were synthesized, followed by pyrolysis to produce carbonized counterparts while preserving the fundamental structure but with altered physicochemical properties. Comparative EOR studies revealed the superior performance of pyrolyzed MOFs, demonstrating that optimized Zn-loading is crucial over Cu-based framework for catalyst performance and durability. Overall, this work highlights the potential of MOF-derived Cu-based catalysts for renewable energy applications and provides insights into optimizing their performance through controlled synthesis and post-treatment strategies.

One-step hydrothermal synthesis of Pt and N-doped carbon quantum dots co-activated as novel electrocatalysts for oxygen reduction reaction

Abstract In this paper, a novel nano-electrocatalyst (Pt@N-CDs/RGO) with reduced graphene oxide as the carrier and platinum (Pt) and nitrogen-doped carbon quantum dots (N-CDs) together as the active sites was prepared by a simple hydrothermal method. By comparing the electrochemical properties of commercial platinum carbon (Pt/C) and Pt@N-CDs/RGO at 20% wt Pt, it was found that Pt@N-CDs/RGO exhibited excellent ORR properties, such as an onset potential (Eonest ) of 1.10 V, a half-wave potential (E1/2) of 0.82 V, a limiting current density of 5.06 mA/cm2, and a number of transferred electrons as high as 3.97. By using the chronoamperometric method (CA) to cycle for 10000 s, it was found that the stability of both, Pt@N-CDs /RGO maintains 18% activity after a cycle of 10000 seconds, which is much higher than Pt/C. The study showcased a new efficient and durable catalyst for PEMFCs.

Improving the durability and anti-poisoning properties of platinum catalysts by carbon shell encapsulation: A promising approach for both cathode and anode catalysts for polymer electrolyte membrane fuel cells

Carbon shell encapsulation has emerged as an effective strategy for enhancing the durability of Pt-based electrocatalysts for polymer electrolyte membrane fuel cells (PEFCs). Here, a nitrogen-doped carbon shell-encapsulated Pt catalyst supported on Ketjen black (Pt@C/KB) was synthesized, and its catalytic performance was characterized. The oxygen reduction reaction (ORR) performance and anti-poisoning properties were investigated in 0.1 M HClO4 with and without H2SO4 or H3PO4 poisoning, using a rotating ring-disk electrode (RRDE) technique. Despite a decrease in the electrochemical surface area (ECSA), Pt@C/KB encapsulated by a thin graphene-like carbon shell (<1 nm thick) showed high selectivity for the four-electron reaction due to its superior anti-poisoning properties, as well as improved ORR activity and durability. The H2O2 yield of Pt@C/KB, the precursor of hydroxyl radicals, was decreased approximately one third compared to bare Pt catalyst and the gap was more pronounced in the low potential (E ≤ 0.1 V/RHE) where close to practical anode potential, suggesting that Pt@C/KB can be applied as a new anode catalyst. Applying carbon core-shell catalysts to both the cathode and anode is a prospectively effective approach for improving the cell performance by improving the ORR activity and anti-poisoning properties, as well as for extending the lifespan of PEFCs.