Tailoring of Surface Acidic Sites in Co-MoS2 Catalysts for Hydrodeoxygenation Reaction

A Comprehensive Review of Catalytic Hydrodeoxygenation of Lignin-Derived Phenolics to Aromatics

Single-ring aromatic compounds including BTX (benzene, toluene, xylene) serve as essential building blocks for high-performance fuels and specialty chemicals, with extensive applications spanning polymer synthesis, pharmaceutical manufacturing, and aviation fuel formulation. Current industrial production predominantly relies on non-renewable petrochemical feedstocks, posing the dual challenges of resource depletion and environmental sustainability. The catalytic hydrodeoxygenation (HDO) of lignin-derived phenolic substrates emerges as a technologically viable pathway for sustainable aromatic hydrocarbon synthesis, offering critical opportunities for lignin valorization and biorefinery advancement. This article reviews the relevant research on the conversion of lignin-derived phenolic compounds' HDO to benzene and aromatic hydrocarbons, systematically categorizing and summarizing the different types of catalysts and their reaction mechanisms. Furthermore, we propose a strategic framework addressing current technical bottlenecks, highlighting the necessity for the synergistic development of robust heterogeneous catalysts with tailored active sites and energy-efficient process engineering to achieve scalable biomass conversion systems.

Sulfur-vacancy engineering of Co9S8-x/Ti3C2Tx-MXene catalyst for efficient oxygen evolution reaction

Integrating conductive supports and modulating electronic structures are widely recognized as effective strategies for improving the catalytic performance of transition metal sulfides. This study demonstrates the simultaneous integration of Co9S8 with two-dimensional Ti3C2Tx-MXene and the introduction of sulfur vacancies (Sv) in Co9S8 through a straightforward sintering process followed by plasma treatment, culminating in the formation of the Co9S8-x/Ti3C2Tx composite. Characterization results demonstrate that the Ti3C2Tx support significantly improves electrical conductivity and promotes the uniform dispersion of Co9S8 nanoparticles. Experimental and theoretical analyses reveal that the introduction of Sv induces charge redistribution and optimizes the adsorption of reaction intermediates. The obtained Co9S8-x/Ti3C2Tx electrode exhibits superior oxygen evolution reaction (OER) performance, achieving an overpotential of 286 mV at a current density of 10 mA cm-2 and a Tafel slope of 76 mV dec-1, outperforming other counterparts and approaching the catalytic performance of commercial RuO2 catalyst. Furthermore, it demonstrates exceptional stability, with a potential shift of only 18 mV during a durability test exceeding 13 h. As an anodic catalyst for water splitting, the Co9S8-x/Ti3C2Tx electrode achieves a low overpotential of 330 mV, highlighting its potential for practical water electrolysis applications. This study offers valuable insights into the design and development of advanced transition metal sulfide-based OER catalysts.

Unlocking the catalytic potential of heterogeneous nonprecious metals for selective hydrogenation reactions

Selective hydrogenation has been employed extensively to produce value-added chemicals and fuels, greatly alleviating the problems of fossil resources and green synthesis. However, the design and synthesis of highly efficient catalysts, especially those that are inexpensive and abundant in the earth's crust, is still required for basic research and subsequent industrial applications. In recent years, many studies have revealed that the rational design and synthesis of heterogeneous catalysts can efficaciously improve the catalytic performance of hydrogenation reactions. However, the relationship between nonprecious metal catalysts and hydrogenation performance from the perspective of different catalytic systems still remains to be understood. In this review, we provide a comprehensive and systematic overview of the recent advances in the synthesis of nonprecious metal catalysts for heterogeneous selective hydrogenation reactions including thermocatalytic hydrogenation/transfer hydrogenation, photocatalytic hydrogenation and electrocatalytic reduction. In addition, we also aim to provide a clear picture of the recent design strategies and proposals for the nonprecious metal catalysed hydrogenation reactions. Finally, we discuss the current challenges and future research opportunities for the precise design and synthesis of nonprecious metal catalysts for selective hydrogenation reactions.

Molybdenum Disulfide-Based Catalysts in Organic Synthesis: State of the Art, Open Issues, and Future Perspectives

In the field of heterogeneous organic catalysis, molybdenum disulfide (MoS2) is gaining increasing attention as a catalytically active material due to its low toxicity, earth abundance, and affordability. Interestingly, the catalytic properties of this metal-based material can be improved by several strategies. In this Perspective, through the analysis of some explicative examples, the main approaches used to prepare highly efficient MoS2-based catalysts in relevant organic reactions are summarized and critically discussed, namely: i) increment of the specific surface area, ii) generation of the metallic 1T phase, iii) introduction of vacancies, iv) preparation of nanostructured hybrids/composites, v) doping with transition metal ions, and vi) partial oxidation of MoS2. Finally, emerging trends in MoS2-based materials catalysis leading to a richer organic synthesis are presented.

A General Synthesis Method for Covalent Organic Framework and Inorganic 2D Materials Hybrids

Two-dimensional (2D) inorganic/organic hybrids provide a versatile platform for diverse applications, including electronic, catalysis, and energy storage devices. The recent surge in 2D covalent organic frameworks (COFs) has introduced an organic counterpart for the development of advanced 2D organic/inorganic hybrids with improved electronic coupling, charge separation, and carrier mobility. However, existing synthesis methods have primarily focused on few-layered film structures, which limits scalability for practical applications. Herein, we present a general synthesis approach for a range of COF/inorganic 2D material hybrids, utilizing 2D inorganic materials as both catalysts and inorganic building blocks. By leveraging the intrinsic Lewis acid sites on the inorganic 2D materials such as hexagonal boron nitride (hBN) and transition metal dichalcogenides, COFs with diverse functional groups and topologies can grow on the surface of inorganic 2D materials. The controlled 2D morphology and excellent solution dispersibility of the resulting hybrids allow for easy processing into films through vacuum filtration. As proof of concept, hBN/COF films were employed as filters for Rhodamine 6G removal under flow-through conditions, achieving a removal rate exceeding 93%. The present work provides a simple and versatile synthesis method for the scalable fabrication of COF/inorganic 2D hybrids, offering exciting opportunities for practical applications such as water treatment and energy storage.

Humidity activated ultra-selective room temperature gas sensor based on W doped MoS2/RGO composites for trace level ammonia detection

The lack of highly efficient, cost effective and stable ammonia gas sensors functionable at room temperature even in extreme humid environments poses significant challenge for the future generation gas sensors. The prime factors that impede the development of such next generation gas sensors are the strong interference of humidity and sluggish selectivity. Herein, we fabricated tungsten doped molybdenum disulphide/reduced graphene oxide composite by an in-situ hydrothermal method to exploit the adsorption, dissolution (solubility), ionization and transmission process of ammonia and thereby to effectuate its trace level detection even in indispensable humid environments. The protype based on 5 at.% Tungsten doped MoS2/RGO (W5) gas sensor exhibited 3.8-fold increment in its response to 50 ppm of ammonia when the relative humidity varied from 20 % to 70 % with ultra-high selectivity at room temperature. The as prepared gas sensor revealed a practical detection limit down to 1 ppm with a substantial response and rapid recovery time. Furthermore, W5 gas sensor exhibited a 42-fold increment in response to 50 ppm of ammonia relative to its pristine (MoS2/RGO) MG composite with a RH of 70 %. The proton hopping mechanism accountable for such an enormous enhancement in ammonia sensing and its potential for breath sensor are briefly annotated.

Unsupported MoS2-Based Catalysts for Bio-Oil Hydrodeoxygenation: Recent Advances and Future Perspectives

In recent years, unsupported MoS₂-based catalysts have been reported as promising candidates in the hydrodeoxygenation (HDO) of bio-oil. However, preparing MoS₂-based catalysts with both high activity and good stability for HDO reaction is still challenging and of great importance. Hence, this mini-review is focused on the recent development of unsupported MoS₂-based HDO catalysts from the understanding of catalyst design. The three aspects including morphology and defect engineering, metal doping, and deactivation mechanism are highlighted in adjusting the HDO performance of MoS₂-based catalysts. Finally, the key challenges and future perspectives about how to design efficient catalysts are also summarized in the conclusions.

Brønsted acid-enhanced CoMoS catalysts for hydrodeoxygenation reactions

Brønsted solid acids greatly promote the hydrodeoxygenation activity of CoMoS catalysts through weakening Car–O bonds by protonation of the OH group.