Development Of Catalysts Research Articles

Establishing Non-Stoichiometric Ti4O7 Assisted Asymmetrical C-C Coupling for Highly Energy-Efficient Electroreduction of Carbon Monoxide.

Exploring an appropriate support material for Cu-based electrocatalyst is conducive for stably producing multi-carbon chemicals from electroreduction of carbon monoxide. However, the insufficient metal-support adaptability and low conductivity of the support would hinder the C-C coupling capacity and energy efficiency. Herein, non-stoichiometric Ti4O7 was incorporated into Cu electrocatalysts (Cu-Ti4O7), and served as a highly conductive and stable support for highly energy-efficient electrochemical conversion of CO. The abundant oxygen vacancies originated from ordered lattice defects in Ti4O7 facilitate the water dissociation and the CO adsorption to accelerate the hydrogenation to *COH. The highly adaptable metal-support interface of Cu-Ti4O7 enables a direct asymmetrical C-C coupling between *CO on Cu and *COH on Ti4O7, which significantly lowers the reaction energy barrier for C2+ products formation. Additionally, the excellent electroconductivity of Ti4O7 benefits the reaction charge transfer through robust Cu/Ti4O7 interface for minimizing the energy loss. Thus, the optimized 20Cu-Ti4O7 catalyst exhibits an impressive selectivity of 96.4 % and ultrahigh energy efficiency of 45.1 % for multi-carbon products, along with a remarkable partial current density of 432.6 mA cm-2. Our study underscores a novel C-C coupling strategy between Cu and the support material, advancing the development of Cu-supported catalysts for highly efficient electroreduction of carbon monoxide.

Understanding the Carbyne Formation from C2H2 Complexes.

Nature chooses a high-valent tungsten center at the active site of the enzyme acetylene hydratase to facilitate acetylene hydration to acetaldehyde. However, the reactions of tungsten-coordinated acetylene are still not well understood, which prevents the development of sustainable bioinspired alkyne hydration catalysts. Here we report the reactivity of two bioinspired tungsten complexes with the acetylene ligand acting as a four-: [W(CO)(C2H2)(PymS)2] (1) and a two-electron donor: [WO(C2H2)(PymS)2] (3), with PMe3 as a nucleophile to simulate the enzyme's reactivity (PymS = 4-(trifluoromethyl)-6-methylpyrimidine-2-thiolate). In dichloromethane, compound 1 was found to react to the cationic carbyne [W≡CCH2PMe3(CO)(PMe3)2(PymS)]Cl (2-Cl) while 3 reacts to the vinyl compound [WO(CH═CHPMe3)(PMe3)3(PymS)]Cl (4-Cl). The formation of the latter follows the common rules applied to η2-alkyne complexes, whereas the carbyne formation was not expected due to the challenging 1,2-H shift. To understand these differences in behavior between seemingly similar acetylene complexes, stepwise addition of the nucleophile in various solvents was investigated by synthetic, spectroscopic, and computational approaches. In this manuscript, we describe that only a four-electron donor acetylene complex can react to the carbyne over the η1-vinyl intermediate and that 1,2-H shift can be assisted by an H-transfer reagent (in this case, the decoordinated PymS ligand). Furthermore, to favor the attack of PMe3 at W coordinated acetylene, the metal center needs to be electron-poor and crowded enough to prevent nucleophile coordination. Finally, the intricate role of the anionic PymS ligand in the vicinity of the first coordination sphere models the potential involvement of amino acid residues during acetylene transformations in AH.

Regulating the Local Spin States in Spinel Oxides to Promote the Activity of Li-CO2 Batteries.

Due to the high energy barrier, slow reaction kinetics, and complex reaction environments of Li-CO2 batteries, the development of durable and efficient catalysts is essential. Transition metal oxides are promising for their availability, stability, and 3d electronic features, with spin states playing an important role in CO2 activation. In this study, the local spin states are regulated by incorporating Ni into Co3O4 and its impact on activity in Li-CO2 batteries is explored. The results show that Ni atoms with high spin states in Ni0.1Co2.9O4 facilitate electron transfer from the catalyst to the unoccupied orbitals of CO2, providing sufficient active sites for the nucleation and growth of small Li2CO3 crystals. These small crystals have a low decomposition barrier, leading to improved battery efficiency. Therefore, Ni0.1Co2.9O4 shows superior catalytic performance with an overpotential of 0.72V and an energy efficiency of ≈70% after 500h. This work provides insights into the relationship between spin states and CO2 reactions, highlighting a promising avenue for developing high-performance metal-CO2 batteries.

Spinel-Based Catalysts That Enable Catalytic Oxidation of Volatile Organic Compounds.

Volatile organic compounds (VOCs) have caused serious harm to human health and ecological environment, and have received much attention in recent years. Despite the successful applications of catalytic combustion of VOCs as the core technology of VOCs removal in industry, the development of efficient catalysts that can mineralize VOCs into nontoxic CO2 and H2O at low temperatures remains a great challenge. Recent studies show that spinel-based materials as efficient catalysts were extensively used in the catalytic oxidation VOCs field due to their synergistic effect, manifold compositions, and electron configurations. However, most of the pollutants are complex, consisting of multiple VOCs, water vapor, CO2, SO2 and other substances, which presents a significant challenge in constructing highly active and stable catalysts. To meet the future demand for efficient catalysts capable of removing various types of VOCs, it is urgent to rationally design and scientifically prepare spinel catalysts based on existing knowledge. This work reviews the research and development of various spinel catalysts with an emphasis on their catalytic performance in VOCs oxidation. The catalytic performance of spinel-based catalysts for different sorts of VOCs was summarized and compared. Moreover, the effects of the reaction conditions on the catalytic performance of spinel-based catalysts were examined to accommodate complicated operating conditions. Subsequently, the regulation of spinel oxides in structure and defect was coherently reviewed to guide the development and design of efficient catalysts. Especially, the research techniques for the reaction mechanism over spinel catalysts were displayed to better deepen the understanding of catalytic oxidation of VOCs. Finally, the current development and challenges were proposed and put forward for future research. This review provided a systematic understanding of the VOCs oxidation over spinel-based catalysts and offered guidance for the development of high-performance catalysts for VOCs elimination.

A Nitrogen- and Carbon-Present Tin Dioxide-Supported Palladium Composite Catalyst (Pd/N-C-SnO2)

For the first time, nitrogen- and carbon-present tin dioxide-supported palladium composite catalysts (denoted as Pd/N-C-SnO2) were prepared via an HCH method (HCH is the abbreviation for the hydrothermal process–calcination–hydrothermal process preparation process). In this work, firstly, three catalyst carriers (denoted as cc) were prepared using a hydrothermal-process-aided calcination method, and catalyst carriers prepared using ammonia monohydrate (NH3∙H2O), N,N-dimethylformamide (C3H7NO) and triethanolamine (C6H15NO3) as the nitrogen sources were nominated as cc1, cc2 and cc3, respectively. Secondly, these catalyst carriers were reacted with palladium oxide monohydrate (PdO·H2O) hydrothermally to generate catalysts c1, c2 and c3. As testified by XRD and XPS, besides carbon materials and the N-containing substances, the main substances of all prepared catalysts were SnO2 and metallic palladium (Pd). Above all things, all resultant catalysts, especially c2, showed a prominent electrocatalytic activity towards the ethanol oxidation reaction (EOR). As indicated by the CV (cyclic voltammetry) results, all fabricated catalysts presented a clear electrocatalytic activity towards the EOR. In the CA (chronoamperometry) measurement, the faradaic current density of EOR measured on c2 at −0.27 V vs. an SCE (saturated calomel electrode) after 7200 s was still maintained at about 5.6 mA cm−2. Preparing a novel catalyst carrier, N-C-SnO2, and preparing a new EOR catalyst, Pd/N-C-SnO2, were the principal dedications of this preliminary work, which was very beneficial to the development of Pd-based EOR catalysts.

Solid waste-derived carbonaceous catalysts for environmental and energy applications

AbstractUrbanization and industrialization generate vast amounts of solid waste, posing significant threats to the biotic and abiotic components of the environment. Solid wastes-derived carbonaceous catalysts (SW-CCs) represent an effective strategy for resource utilization, and SW-CCs are gradually applied in environmental remediation and energy fields. However, the effects of the properties of SW-CCs on their catalytic activity remain inadequately understood. A comprehensive review of the applications of SW-CCs in environmental remediation and energy fields is yet to be achieved. It is necessary to systematically review the latest research progress of SW-CCs in environmental remediation and energy fields. First of all, this review summarizes the influences of various factors on the properties of SW-CCs and how these properties affect the catalytic activity. Subsequently, it explores the recent research progress and existing issues in the applications of SW-CCs in environmental remediation (persulfate activation, photocatalysis, and Fenton-like oxidation) and the energy sector (H2 production, biodiesel production, and CO2 conversion). Finally, future research prospects and recommendations are provided to facilitate further development and application of SW-CCs. This review offers new insights into the resource utilization of solid waste and the development of efficient and practical carbonaceous catalysts. Graphical Abstract

Dual Active Sites with Charge‐asymmetry in Organic Semiconductors Promoting C−C Coupling for Highly Efficient CO2 Photoreduction to Ethanol

AbstractSelective CO2 photoreduction into high‐energy‐density and high‐value‐added C2 products is an ideal strategy to achieve carbon neutrality and energy shortage, but it is still highly challenging due to the large energy barrier of the C−C coupling step and severe exciton annihilation in photocatalysts. Herein, strong and localized charge polarization is successfully induced on the surface of melon‐based organic semiconductors by creating dual active sites with a large charge asymmetry. Confirmed by multiscale characterization and theoretical simulations, such asymmetric charge distribution, originated from the oxygen dopants and nitrogen vacancies over melon‐based organic semiconductors, reduces exciton binding energy and boosts exciton dissociation. The as‐formed charge polarization sites not only donate electrons to CO2 molecules but also accelerate the coupling of asymmetric *CO*CO intermediates for CO2 photoreduction into ethanol by lowering the energy barrier of this process. Consequently, an exceptionally high selectivity of up to 97 % for C2H5OH and C2H5OH yield of 0.80 mmol g−1 h−1 have been achieved on this dual active sites organic semiconductor. This work, with its potential applicability to a variety of non‐metal multi‐site catalysts, represents a versatile strategy for the development of advanced catalysts tailored for CO2 photoreduction reactions.

The Development, Essence and Perspective of Nitrogen Reduction to Ammonia.

Ammonia plays a pivotal role in agriculture and meanwhile holds promising potential as an energy vector for the hydrogen economy, where the nitrogen reduction to ammonia is a critical pathway for achieving sustainable development. Over the past hundred years, ammonia synthesis has undergone several breakthrough developments from Haber-Bosch process to photo/electro-catalysis and Li-mediated strategy, but still faces the challenges of low yield rate, selectivity and efficiency. Therefore, there is a pressing demand to develop efficient and green ammonia synthesis from nitrogen. This review summarizes the development of the nitrogen reduction to ammonia, highlighting six milestones during the whole journey. From the development direction, this work finds and extracts the essence of ammonia synthesis, that is the reaction pathways are affected by the energy barrier of reaction intermediates, which can be altered by proton sources, auxiliaries and catalysts. Then this work discusses the detailed overview of the significant development of proton source, auxiliaries and catalysts. Finally, based on the essence, the possible opportunities of ammonia synthesis from nitrogen reduction are presented, including the design of new ammonia synthesis pathways and efficient catalysts. The deep insight of nitrogen reduction to ammonia will provide a design guidance for efficient ammonia synthesis.

Low-energy photoredox catalysis.

With the advent of photoredox catalysis, new synthetic paradigms have been established with many novel transformations being achieved. Nevertheless, modern photoredox chemistry has several drawbacks, namely, deficiencies in reaction efficiency and scalability. Furthermore, wavelengths of light in excess of the energy required for a chemical reaction are often used. In this Review, we document recent developments of low-energy light-absorbing catalysts and their cognate photochemical methods, advantageously mitigating off-cycle photochemical reactivity of excited-state species in the reaction mixture and improving batch scalability of photochemical reactions. Finally, developments in red-light photoredox catalysis are leading the next-generation applications to polymer science and biochemistry-chemical biology, enabling catalytic reactions within media composites - including mammalian tissue - that are historically recalcitrant with blue-light photoredox catalysis.

High‐Throughput Screening Technologies of Efficient Catalysts for the Ammonia Economy

AbstractDriven by the growing global demand for sustainable energy, ammonia is gaining recognition as a crucial energy carrier with the potential for widespread manufacturing. This has spurred the emergence of a “sustainable ammonia economy”. Efficient catalyst development is paramount to achieving this purpose. Although the traditional trial‐and‐error methods have led to substantial progress, they are inherently time‐consuming. In recent years, high‐throughput screening strategies are revolutionizing catalyst discovery, offering an efficient and cost‐effective approach for identifying high‐performance catalysts across various processes within the ammonia economy. This review explores recent advancements in these rapid catalyst screening techniques for ammonia‐based processes. By outlining the general screening principles and the key steps involved in the computational analysis of catalysts relevant to different stages of the ammonia economy, this review aims to provide fundamental insights for the development of novel catalysts using these accelerated methods.

Tuning the Electronic Properties of CumAgn Bimetallic Clusters for Enhanced CO2 Activation

The urgent demand for efficient CO2 reduction technologies has driven enormous studies into the enhancement of advanced catalysts. Here, we investigate the electronic properties and CO2 adsorption properties of CumAgn bimetallic clusters, particularly Cu4Ag1, Cu1Ag4, Cu3Ag2, and Cu2Ag3, using generalized gradient approximation (GGA)/density functional theory (DFT). Our results show that the atomic arrangement within these clusters drastically affects their stability, charge transfer, and catalytic performance. The Cu4Ag1 bimetallic cluster emerges as the most stable structure, revealing superior charge transfer and effective chemisorption of CO2, which promotes effective activation of the CO2 molecule. In contrast, the Cu1Ag4 bimetallic cluster, in spite of comparable adsorption energy, indicates insignificant charge transfer, resulting in less pronounced CO2 activation. The Cu3Ag2 and Cu2Ag3 bimetallic clusters also display high adsorption energies with remarkable charge transfer mechanisms, emphasizing the crucial role of metal composition in tuning catalytic characteristics. This thorough examination provides constructive insights into the design of bimetallic clusters for boosted CO2 reduction. These findings could pave the way for the development of cost-effective and efficient catalysts for industrial CO2 reduction, contributing to global efforts in carbon management and climate change mitigation.

Development and Application of Green Catalysts: Challenges, Optimization, and Future Perspectives

This paper comprehensively reviews the development and application of green catalysts in modern chemical industries, with a focus on analyzing the significant advantages of various types of green catalysts, such as metal-organic frameworks (MOFs) and enzyme catalysts, in improving reaction efficiency, reducing energy consumption, and minimizing by-product generation. The paper delves into the design and synthesis of green catalysts, optimization of reaction conditions, and technologies for catalyst recycling and regeneration, highlighting their key roles in enhancing catalyst performance. Despite challenges such as high material costs, complex synthesis processes, and issues with stability and durability in practical applications, continuous technological innovation and process improvements offer promising solutions. As global attention to sustainable development grows, green catalysts are expected to have broad applications in emerging fields such as carbon capture and utilization, renewable energy conversion, and environmental remediation, thereby driving the green transformation and low-carbon development of the chemical industry and providing strong technical support for achieving global sustainability goals.

Understanding the Roles and Regulation Methods of Key Adsorption Species on Ni-Based Catalysts for Efficient Hydrogen Oxidation Reactions in Alkaline Media.

This review focuses on recent advancements in the development and understanding of nickel-based catalysts for the hydrogen oxidation reaction in alkaline media. Given the economic and environmental limitations associated with platinum group metals, nickel-based catalysts have emerged as promising alternatives due to their abundance, lower cost, and comparable catalytic properties. The review begins with an exploration of the fundamental HOR mechanisms, emphasizing the key roles of the reactive species in optimizing the catalytic activity of Ni-based catalysts. Thermodynamic and stability optimizations of nickel-based catalysts are thoroughly examined, focusing on alloying strategies, heteroatom incorporation, and the use of various support materials to enhance their catalytic performance and durability. The review also addresses the challenge of catalyst poisoning, particularly by carbon monoxide, and evaluates the effectiveness of different approaches to improve poison resistance. Finally, the review concludes by summarizing the key findings and proposing future research directions to further enhance the efficiency and stability of nickel-based catalysts for practical applications in anion exchange membrane fuel cells. The insights gained from this comprehensive analysis aim to contribute to the development of cost-effective and sustainable catalysts and facilitate the broader adoption of AEMFCs in the quest for clean energy solutions.

Advances in Carbon Dioxide Catalytic Conversion and Applications

To achieve the global climate goals set out in the Paris Agreement, reducing carbon dioxide (CO2) emissions and utilizing resources have become key areas of focus within international energy technology research and development. CO2 can be converted into high-value chemicals, including hydrocarbons, alcohols and hydrocarbons, through the catalytic technology. This process can potentially address environmental issues while generating economic benefits. This paper presents a review of the principal products resulting from the catalytic conversion of CO2, together with an examination of their practical applications. These include hydrogenation of olefins, light aromatics, methanol, polyols, and synthetic bioconversion technologies. The development of catalysts with high conversion and selectivity represents a key area of current research. In the future, it will be necessary to combine physical, chemical, and biological technologies to establish an engineered heterogeneous carbon sequestration technology system to achieve the efficient conversion and utilization of CO2.

Catalytic Cracking of Liquefied Petroleum Gas (LPG) to Light Olefins Using Zeolite-based Materials: Recent Advances, Trends, Challenges and Future Perspectives.

The catalytic cracking of liquefied petroleum gas (LPG) has attracted significant attention due to its importance in producing valuable feedstocks for the petrochemical industry. This review provides an overview of recent developments in zeolite-based catalyst technology for converting LPG into light olefins. Catalytic cracking utilizes zeolite-based catalysts usually associated with stability challenges, such as coking and sintering. The discussion focused on the underlying mechanisms that govern the catalytic cracking process and provided insights into the complex reaction pathways involved. A comprehensive analysis of various strategies employed for improving the effectiveness of zeolite catalysts has been discussed in this review. These strategies encompass using transition metals to modify catalyst properties, treatments involving phosphorous modification, alkaline earth metals, and alkali metals to alter the acidity level of the zeolites. The elucidation of the impact of silica-to-alumina ratios in zeolites and the development of hierarchical zeolite-based catalysts through top-down and bottom-up methodologies are also discussed.

Hydrogenation Reactions with Heterobimetallic Complexes

AbstractHydrogenations are fundamentally and industrially important reactions that are atom economical paths to synthesize value‐added products from feedstock chemicals. The cooperative effects of two or more metal centers in multimetallic active sites is a successful strategy to activate small molecules and facilitate catalytic reactions, and this strategy has been recently applied to catalytic hydrogenation reactions. Furthermore, heterobimetallic complexes have been well‐documented to provide novel reaction pathways and improved selectivity, compared to their homo‐bimetallic and monometallic analogues. This minireview provides a historical perspective on the development of heterobimetallic catalysts for the hydrogenation of unsaturated substrates and describes recent developments in this burgeoning research area.

Surface Coordination Chemistry of Graphitic Carbon Nitride from Ag Molecular Probes.

Graphitic carbon nitride (g-C3N4) has gained significant attention for its catalytic properties,especiallyin the development of Single Atom Catalysts (SACs).However,the surface chemistry underlying the formation of these isolated metal sites remains poorly understood.In thisstudyweemploy Surface OrganoMetallic Chemistry (SOMC) together with advanced microscopic and spectroscopic techniquesfor an in-depth analysis of functionalizedg-C3N4materials, where tailored organosilver probe molecules are used to monitor surface processes and characterize resulting surface species. Amulti-technique approach-including high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM), X-ray absorption spectroscopy (XAS), and multinuclear solid-state Nuclear Magnetic Resonance spectroscopy (ssNMR),coupled with density functional theory (DFT) calculations- identifies three primary surface speciesin Ag-functionalized g-C3N4:bis-NHC-Ag+, dispersed Ag+sites, andphysisorbed molecular precursor.These findings highlight a dynamic grafting process and provide insights into the surface coordination chemistryof functionalizedg-C3N4materials.

Concentrated C2+ Alcohol Production Enabled by Post-Intermediate Modulation and Augmented CO Adsorption in CO Electrolysis.

The electrocatalytic synthesis of multicarbon products from CO2/CO feedstock represents a sustainable method for chemical production with a reduced carbon footprint. Traditional copper catalysts predominantly produce alkenes, but generating valuable and versatile C2+ alcohols, especially high-energy-density C3 alcohols, has been challenging due to issues with selectivity, activity, and stability. Here, we present the construction of Ru-doped Cu nanowires that enhance the selectivity of n-PrOH and C2+ alcohols. In situ Raman spectroscopy shows that our approach promotes both *CO binding and availability, particularly facilitating the formation of high-frequency-bound *CO (*COHFB) and maintaining multiple *CO adsorption modes on Ru-modified and bare low-coordinated Cu nanowires. Density-functional theory (DFT) simulations illustrate that introducing Ru species onto a low-coordinated Cu step surface simultaneously stabilizes CO and alcohol-related intermediates, shifting the dominant reaction pathway toward alcohols and facilitating CO-C2 coupling at the expense of ethylene selectivity. In an alkaline gas-diffusion electrolyzer, we attained a maximum Faradaic efficiency (FE) of 35.9% for n-PrOH and 62.4% for the total C2+ alcohols. Optimizing parameters in the membrane electrode assembly (MEA) system enabled the one-pot generation and separation of C2+ alcohols, achieving a record concentration of 18.8 wt % (4.2 wt % n-PrOH and 14.6 wt % EtOH) with nearly 100% purity at 200 mA/cm2 over 100 h. This work not only provides new insights and guidance for the development of future catalysts from the perspectives of surface science and mechanisms but also highlights the importance of coupling material engineering with reactor engineering to optimize the production process of high-value alcohol products.

N, F Co-Doped Carbon Material Self-Supporting Cathode for High-Performance Lithium-Oxygen Batteries.

The Li-O2 battery has emerged as a promising energy storage system due to its exceptionally high theoretical energy density of 3500 Wh kg-1. However, the sluggish kinetics associated with the formation and decomposition of discharge product Li2O2 poses several challenges in Li-O2 batteries, including excessive over-potential, limited rate performance, and reduced actual specific energy. Consequently, the development of cost-effective cathode catalysts with enhanced catalytic activity and long-term stability represents a viable approach to address these challenges. In this study, commercial melamine foam is utilized as a precursor material which was subjected to pyrolysis at elevated temperatures with PVDF to synthesize N, F co-doped self-supporting carbon cathode (NF-NSC). Remarkably, thanks to the synergistic effects of N, F heteroatomic in conjunction with the inherent three-dimensional reticular porous structure, NF-NSC exhibited enhanced electrochemical performance when utilized in Li-O2 batteries. Specifically, the NF-NSC cathode demonstrated an impressive discharge specific capacity of up to 35204 mAh g-1 alongside a low over-potential (0.86 V) and excellent cycling stability (146 cycles).

A multi-site strategy for boosting Li-CO2 batteries performance

Herein, we develop a multi-site strategy to boost Li-CO2 battery performance using Co nanoparticles (NPs) loaded nitrogen-doped holey carbon nanotubes (Co@N-hCNT) as high-efficiency cathode catalyst. The Co@N-hCNT possesses high-efficiency multiple active sites of defects, nitrogen sites and Co NPs for reversible conversion of insulating Li2CO3 as well as rapid charge and ion transport provided by the nitrogen-doped holey CNTs. Benefiting from these excellent properties, the as-assembled Li-CO2 battery with Co@N-hCNT cathode shows outstanding electrochemical performance with a low overpotential of 1.03 V at 0.05 A g−1 and a high full discharge capacity of 27952 mA h g−1 at 0.2 A g−1. More importantly, the Li-CO2 battery with Co@N-hCNT exhibits a long-term durability over 220 cycles even at a high current density of 0.5 A g−1. This work opens a new venture for the development of high-efficiency cathode catalysts for Li-CO2 batteries and beyond via a multi-site strategy.