Hydrogenation Research Articles

Highly-Efficient Reusable [Silica@Iminophosphine-FeII] Hybrids for Hydrogen Production via Formic Acid and Formaldehyde Dehydrogenation.

The use of hybrids, developed by grafting homogeneous catalysts onto supporting materials, has already demonstrated significant potential in various catalytic processes. These systems combine the advantages of homogeneous catalysts, such as high activity and selectivity, with those of solid supports, including enhanced recyclability. Catalytic hydrogen (H2) production via dehydrogenation of C1 organic molecules targeting its use in fuel cells is a contemporary scientific issue directly connected with climate crisis. Here, Iminophospine hybrid [SiO2@benzNP] and its reduced analogue [SiO2@benzNHP] were synthesized, covalently grafted on colloidal SiO2, fully characterized (FT-IR, RAMAN, TGA, ssNMR, BET), and used for in-situ synthesis of [SiO2@benzNP-FeII] and [SiO2@benzNHP-FeII] catalytic complexes for H2 production from formic acid (HCOOH) and formaldehyde (HCHO), at 80 °C. In HCOOH, both heterogenized catalysts exhibit high selectivity, producing H2 and CO2 in a 1 : 1 ratio, without CO contamination, making them ideal for fuel cell applications. [SiO₂@benzNHP-FeII] catalyst demonstrated superior performance in both substates. In HCOOH dehydrogenation, over 82,000 turnover number (TONs) were achieved and retained its efficiency for over five cycles, without any further metal addition. In HCHO dehydrogenation, it showed excellent efficiency as well, achieving 1.3 L of pure H2 with TONs exceeding 7,000, in 3 consecutive uses. Advanced spectroscopic analysis confirmed the stability and structural integrity of the catalysts, linking the Schiff base reduction and N-H groups to enhanced activity, durability and reusability. This study demonstrates the potential of hybrid materials with non-noble metals for cost-effective and sustainable H2 production, paving the way for scalable renewable energy solutions.

Electrocatalytic Alkene Hydrogenation/Deuteration.

Traditional reductions of alkenes, such as using stoichiometric reductants with waste generation and catalytic hydrogenation with high-pressure H2, are accompanied by environmental or safety issues. Herein, we demonstrated a universal method for the electrocatalytic hydrogenation and deuteration of alkenes with modified electrodes under ambient temperature. The key M-H/M-D species for alkene reduction were generated from the electrolysis of H2O/D2O on modified electrodes, which avoided the usage of H2 and D2. Mono-, di-, tri-, and tetra-substituted alkenes were successfully reduced in this electrocatalytic system using H2O and D2O as hydrogen and deuterium sources. Electron-donating/-withdrawing alkenes, alkenes with other easily reducible functional groups, and complicated natural products and drugs were all reductive hydrogenated and deuterated with excellent yields (85 examples, yields up to 99%). Faraday efficiency of this efficient method could reach 84%. Moreover, the catalytic amount of metal could decrease to less than 0.01 mol %.

Size-Dependent Fe-Based Catalysts for the Catalytic Transfer Hydrogenation of α,β-Unsaturated Aldehydes.

Metal-based catalysts ranging from nanoparticles (NPs) to the atomic level usually exhibit varying catalytic performance. The underlying size effect is both fascinating and evident. This study thoroughly investigates the size-dependent effects of Fe-based catalysts on catalytic transfer hydrogenation (CTH) of furfural (FF) at the atomic level. Fe was precisely loaded onto N-doped porous carbon in three forms: single atoms (Fe-SAs/NC), atomic clusters (Fe-ACs/NC), and nanoparticles (Fe-NPs/NC). This was achieved through meticulous control of the iron precursor composition. Remarkably, Fe-SAs/NC exhibited exceptional catalytic efficiency, achieving an FF conversion of 91.3% and a turnover frequency (TOF) of 262.3 h-1 at 110 °C, which is 9.2 times higher than Fe-ACs/NC and an impressive 93.7 times higher than Fe-NPs/NC. The high selectivity of Fe-SAs/NC toward furfuryl alcohol was further substantiated by theoretical calculations. These calculations indicated the benefits from the η1(O)-aldehyde adsorption configuration, formed by the vertical adsorption of FF molecules on the Fe-N4 active sites. Geometrical optimization of the catalyst at the atomic scale enhances its intrinsic catalytic activity and selectivity. The proposed size effect on catalytic activity provides deeper insights into the mechanism of single-atom catalytic hydrogenation and contributes to the exploration of high-performance catalysts at the atomic level.

Fabrication of tannic acid promoted lignin-MOF hybrids derived catalysts for catalytic transfer hydrogenation of 5-hydroxymethylfurfural

Fabrication of tannic acid promoted lignin-MOF hybrids derived catalysts for catalytic transfer hydrogenation of 5-hydroxymethylfurfural

Recent developments on selective homogeneous catalytic transfer hydrogenation of C C using methanol and ethanol

Recent developments on selective homogeneous catalytic transfer hydrogenation of C C using methanol and ethanol

Ozonation pretreatment-assisted catalytic hydrogenation for efficient depolymerization of lignin

Ozonation pretreatment-assisted catalytic hydrogenation for efficient depolymerization of lignin

3D-printed packed bed reactor for continuous catalytic hydrogenation of nitroaromatic compounds

3D-printed packed bed reactor for continuous catalytic hydrogenation of nitroaromatic compounds

Bio-Based Surfactants via Borrowing Hydrogen Catalysis.

A borrowing hydrogen approach to produce bio-based surfactants is described. The process utilizes ubiquitous amino acids and common alcohols without protecting group manipulations. Surfactants are synthesized in a single step using a commercially available ruthenium-based catalyst in a waste-free manner with nearly ideal atom economy. The versatility of the products is shown by further derivatization resulting in novel Gemini surfactants and a related quaternary ammonia salt. The analysis of selected compounds shows remarkable properties as surfactants. Further studies show their potential biodegradability in nature, which enhances the broad application profile of the sustainable products prepared in this study.

Vapor-phase hydrogenation of citronellal over silica-supported copper prepared via organic additive-assisted impregnation protocol

Abstract The hydrogenation of citronellal to citronellol proceeded over SiO2-supported copper (Cu/SiO2) catalysts prepared by organic additive-assisted impregnation protocol. Introducing Cu species on SiO2 support reduced the rate of the cyclization of citronellal to isopulegol and promoted the formation of citronellol. The utilization of organic additives, especially glucose, highly dispersed Cu nanoparticles, i.e., increased Cu surface area, which promoted catalytic hydrogenation activity. The proportional correlation between Cu surface area and the formation rate of citronellol substantiated this behavior.

Catalytic Hydrogenation of CO2 by Direct Air Capture to Valuable C1 Products Using Homogenous Catalysts.

Growing atmospheric CO2 concentrations are a global concern and a primary factor contributing to global warming. Development of integrated CO2 capture and conversion protocols is necessary to mitigate this alarming challenge. Though CO2 hydrogenation to produce formic acid and methanol has seen many strides in the past decades, most studies utilize pure CO2 for this transformation. The CO2 concentration in the atmosphere stands at 400 ppm and reports that utilize direct air capture as the strategy to capture CO2 and utilize it for production of formic acid and methanol have only been reported in the past few years. This perspective summarizes such reports with a focus on the CO2-capturing additive, reaction solvent, and the molecular catalyst used to affect the transformation.

Optimized Pt–Co/BN Catalysts for Efficient NaBH4 Hydrolysis

The hydrolysis of sodium borohydride is a promising method for generating hydrogen, which can be released under controlled conditions using heterogeneous catalytic systems. Despite significant advancements in catalyst development, no single material meets the requirements for mobile applications. This limitation is primarily due to the suboptimal performance of catalysts in terms of hydrogen production efficiency and stability. To enhance the catalytic performance of sodium borohydride hydrolysis, a boron oxide‐coated Co–Pt/boron nitride (BN) nanocomposite material has been developed, leveraging the oxidative support–metal strong interaction. The results demonstrate that CO2 oxidation etching of the BN facilitates the migration of boron oxide to the Co–Pt nanoparticles, forming a structurally robust coating layer. This configuration exhibits a strong synergistic effect between Co and Pt, significantly enhancing catalytic hydrogen production efficiency. Furthermore, the boron oxide overlayer effectively stabilizes the catalyst structure by preventing metal component loss and the deposition of sodium borate on the metal surface. The surface BOx also modulates the electronic properties of the bimetallic active sites. Ultimately, the optimal 0.4%Pt–5%Co/BN catalyst achieves a high hydrogen generation rate of 8272 mL·min−1·gmetal−1 and turnover frequency of 668 min−1 at room temperature while retaining 90.1% of its initial intrinsic activity after ten cycles.

Photoelectrochemical and Catalytic Hydrogen Generation from Hydrolysis of NaBH4 using Ruthenium and Platinum Decorated ZnO/TiO2 Heterojunction Thin Film Electrodes

Photoelectrochemical and Catalytic Hydrogen Generation from Hydrolysis of NaBH4 using Ruthenium and Platinum Decorated ZnO/TiO2 Heterojunction Thin Film Electrodes

Operando Unveiling of Hydrogen Spillover Mechanisms on Tungsten Oxide Surfaces.

Hydrogen spillover is an important process in catalytic hydrogenation reactions, facilitating H2 activation and modulating surface chemistry of reducible oxide catalysts. This study focuses on the operando unveiling of platinum-induced hydrogen spillover on monoclinic tungsten trioxide (γ-WO3), employing ambient pressure X-ray photoelectron spectroscopy, density functional theory calculations and microkinetic modeling to investigate the dynamic evolution of surface states at varied temperatures. At room temperature, hydrogen spillover results in the formation of W5+ and hydrogen intermediates (hydroxyl species and adsorbed water), facilitated by Pt metal clusters. With increasing temperature, water desorption, reverse hydrogen spillover and surface-to-bulk diffusion of hydrogen atoms compete with each other, leading initially to reoxidation and then further reduction of W atoms in the near-surface. The combined experimental results and simulations provide a comprehensive understanding of the mechanisms underlying hydrogen interaction with reducible metal oxides, lending insights of relevance to the design of enhanced hydrogenation catalysts.

Ultrasonically Activated Liquid Metal Catalysts in Water for Enhanced Hydrogenation Efficiency.

Hydride (H-) species on oxides have been extensively studied over the past few decades because of their critical role in various catalytic processes. Their syntheses require high temperatures and the presence of hydrogen, which involves complex equipment, high energy costs, and strict safety protocols. Hydride species tend to decompose in the presence of atmospheric oxygen and water, which reduces their catalytic activities. These challenges highlight the need for further research to improve the stability and efficiency of catalytic processes and develop safer and cost-effective synthesis methods. This paper introduces an ultrasonic fabrication method for gallium hydride species on liquid metal (LM) nanoparticles (Ga-H@LM NPs) in water and describes the evaluation of their catalytic properties. The Ga-H@LM NPs were synthesized by dispersing liquid metals of eutectic gallium-indium in water using a two-step ultrasonication process in an ice bath. The presence of Ga-H species was confirmed by Fourier-transform infrared spectroscopy. The Ga-H@LM NPs demonstrated the rapid catalytic hydrogenation of 4-nitrophenol and reductive degradation of azo dyes within minutes without the need for external reducing agents like NaBH4. The proposed mechanism involves high-energy ultrasonic cavitation at the interface between LM NPs and water, which promotes the formation of H2 from water and its activation to form Ga-H on particles surface during ultrasonication. This study has significant implications for advancing the field of catalysis because it provides a novel and efficient catalytic method for the synthesis of stable hydride species on gallium oxides.

Lignin-Based Nanoparticles Stabilized Pickering Emulsion for Enhanced Catalytic Hydrogenation.

The development of green and easily regulated amphiphilic particles is crucial for advancing Pickering emulsion catalysis. In this study, lignin particles modified via sulfobutylation were employed as solid emulsifiers to support Pd nanoparticles (NPs), thereby enhancing the catalytic efficiency of biphasic reactions. Sulfobutylation of lignin effectively adjusted the hydrophilic-hydrophobic balance, resulting in controlled emulsion types and droplet sizes. Pd NPs were loaded onto lignin with a 50% sulfobutylation ratio through the in situ reduction of active functional groups, further stabilized by the cross-linked network structure of lignin. In the hydrogenation of nitrobenzene, the Lig-50S-0.6Pd catalyst exhibited superior activity compared to traditional Pd/C catalysts, which is attributed to the high retention of active sites and increased interfacial area. This work underscores the potential for designing lignin-based amphiphilic particles and developing Pickering emulsion-enhanced reactions.

B, N Codoped Defective Reduced Graphene Oxide as a Highly Efficient Frustrated Lewis Pairs Catalyst for the Selective Hydrogenation of α,β-Unsaturated Aldehydes to Unsaturated Alcohols.

The development of all-solid-state frustrated Lewis pairs (FLPs) metal-free hydrogenation catalysts with excellent activity and stability remains a significant challenge. In this work, B, N codoped FLPs catalysts (De-rGO-NxBy) were prepared by the strategy of fabricating carbon defects and heteroatom doping on the surface of reduced graphene oxide and applied in the selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols. It was found that electron-rich pyridine-N (Lewis base) and adjacent electron-deficient B-N (Lewis acid) sites could be constructed on the surface of reduced graphene oxide using dicyandiamide and metaboric acid as N and B sources, thus forming FLPs sites. More importantly, the constructed carbon defects could facilitate the formation of pyridinic-N/B-N FLPs sites, thereby improving the catalytic hydrogenation activity and the selectivity to unsaturated alcohols. Furthermore, in situ DRIFTS and DFT calculations show that the pyridinic-N/B-N FLPs sites can efficiently activate the C═O of aldehydes and H2 molecules with only 0.53 eV dissociation energy of the H-H bond. Also, the catalyst presents excellent catalytic performance in the transfer hydrogenation reactions with cyclohexanol and its derivatives as hydrogen sources. This study provides new ideas for the design and preparation of all-solid-state FLPs metal-free catalysts and promotes the green synthesis of unsaturated alcohols.

Tuning Fork Scanning Electrochemical Cell Microscopy for Resolving Morphological and Redox Properties of Single Ag Nanowires.

We report a Tuning Fork Scanning Electrochemical Cell Microscopy (TF-SECCM) technique for providing morphological and electrochemical information on single redox-active entities. This new operation configuration of SECCM utilizes an electrolyte-filled nanopipette tip mounted onto a tuning fork force sensor to obtain a precise tip-sample distance control and surface morphological mapping capabilities. Redox activities of regions of interest (ROIs) can be investigated by scanning electrode potential by moving the nanopipette to any target regions while maintaining the constant force engagement of the tip with the sample. Using silver nanowires (Ag NWs) as a model system due to their extensive utilization in energy and sensing devices, TF-SECCM provides not only the topography of single Ag NWs but also their distinctive redox activities, catalytic hydrogen evolution reaction (HER) activities, and electrolyte anion adsorption/desorption features in contrast to NW bundles and a supporting substrate.

Research on the Performance Optimization of Molybdenum Disulfide for Multifunctional Applications

Molybdenum disulfide (MoS2), as a typical transition metal chalcogenide compound, has emerged as a research hotspot in nanomaterials due to its excellent electrochemical properties and catalytic activity. However, conventional MoS2 exhibits certain limitations in terms of its catalytic performance, electrical conductivity, and cycling stability. To address these issues, this paper aims to explore the improvement of the multifunctional performance of MoS2 via different performance optimisation strategies, such as heteroatom doping, semiconductor composites, as well as metallic and non-metallic loading. By reviewing and analyzing the relevant literature on the performance enhancement of MoS2 in recent years, this paper summarizes the specific applications and effects of these optimization strategies, highlighting that they significantly improve the performance of MoS2 in fields such as optics, electrochemical catalysis, lithium batteries, and supercapacitors, particularly in terms of catalytic activity, electrical conductivity, and cycling stability. The results indicate that the optimisation of MoS2 performance provides an important theoretical basis and practical guidance for its application in energy storage and catalytic hydrogen evolution.

Comparative study of the reaction characteristics and kinetics of catalytic hydrogenation involving propylene, 1-butene, and their mixture over Pt/ZrO2

Comparative study of the reaction characteristics and kinetics of catalytic hydrogenation involving propylene, 1-butene, and their mixture over Pt/ZrO2

Weakly Coordinating Anionic Microporous Polymer Networks as Scaffold for Molecular Gas Phase Hydrogenation Catalysis

Anionic microporous polymer networks are prepared from a fluorinated tetraarylborate precursor via the Yamamoto reaction. The charge density can be continuously varied by adjusting the ratio of a neutral tetraphenylmethane comonomer. The obtained polymer networks are stable under ambient conditions and exhibit a surface area of up to 1500 m2 g‐1. Cationic molecular complexes can be embedded in the anionic network by simple ion exchange, making them viable for gas phase catalytic reactions. In this case, the cationic complex of the Crabtree’s catalyst is introduced to prepare a solid material for the gas phase hydrogenation of ethylene to ethane at room temperature.