Molybdenum Selenide Electrocatalysts for Electrochemical Hydrogen Evolution Reaction

Research Advances of Cathode Materials for Rechargeable Aluminum Batteries

Rechargeable aluminum ion batteries (AIBs) have recently gained widespread research concern as energy storage technologies because of their advantages of being safe, economical, environmentally friendly, sustainable, and displaying high performance. Nevertheless, the intense Coulombic interactions between the Al3+ ions with high charge density and the lattice of the electrode body lead to poor cathode kinetics and limited cycle life in AIBs. This paper reviews the recent advances in the cathode design of AIBs to gain a comprehensive understanding of the opportunities and challenges presented by current AIBs. In addition, the advantages, limitations, and possible solutions of each cathode material are discussed. Finally, the future development prospect of the cathode materials is presented.

Recent Advancements on Sustainable Electrochemical Water Splitting Hydrogen Energy Applications Based on Nanoscale Transition Metal Oxide (TMO) Substrates

The development of green hydrogen generation technologies is increasingly crucial to meeting the growing energy demand for sustainable and environmentally acceptable resources. Many obstacles in the advancement of electrodes prevented water electrolysis, long thought to be an eco-friendly method of producing hydrogen gas with no carbon emissions, from coming to fruition. Because of their great electrical conductivity, maximum supporting capacity, ease of modification in valence states, durability in hard environments, and high redox characteristics, transition metal oxides (TMOs) have recently captured a lot of interest as potential cathodes and anodes. Electrochemical water splitting is the subject of this investigation, namely the role of transition metal oxides as both active and supportive sites. It has suggested various approaches for the logical development of electrode materials based on TMOs. These include adjusting the electronic state, altering the surface structure to control its resistance to air and water, improving the flow of energy and matter, and ensuring the stability of the electrocatalyst in challenging conditions. In this comprehensive review, it has been covered the latest findings in electrocatalysis of the Oxygen Evolution Reaction (OER) and Hydrogen Evaluation Reaction (HER), as well as some of the specific difficulties, opportunities, and current research prospects in this field.

FeSe2 and Its Composites for Pollutants Removal: Synthesis, Mechanisms, and Application Potential

In recent years, the research of FeSe2 and its composites in environmental remediation has been gradually carried out. And the FeSe2 materials show great catalytic performance in photocatalysis, electrocatalysis, and Fenton-like reactions for pollutants removal. Therefore, the studies and applications of FeSe2 materials are reviewed in this work, including the common synthesis methods, the role of Fe and Se species as well as the catalyst structure, and the potential for practical environmental applications. Hereinto, it is worth noting in particular that the lower-valent Se (Se2-), unsaturated Se (Se-), and Se vacancies (VSe) can play different roles in promoting pollutants removal. In addition, the FeSe2 material also demonstrates high stability, reusability, and adaptability over a wider pH range as well as universality to different pollutants. In view of the overall great properties and performance of FeSe2 materials compared with other typical Fe-based materials, it deserves and needs further research. And finally, this paper presents some challenges and perspectives in future development, looking forward to providing helpful guidance for the subsequent research of FeSe2 and its composites for environmental application.

A toluidine blue/porous organic polymer/2D MoSe2 nanocomposite as an electrochemical signaling platform for a sensitive label-free aflatoxin B1 bioassay in some crops

A label-free electrochemical immunosensor using a toluidine blue (TB)/porous organic polymer (POP)/two-dimensional molybdenum diselenide (2D MoSe2) nanocomposite is developed for highly sensitive detection of aflatoxin B1 (AFB1) in selected crops. A POP/2D MoSe2 composite material is employed to modify the surface of a screen-printed carbon electrode (SPCE). Subsequently, TB is adsorbed on the modified SPCE surface, and the resulting TB/POP/2D MoSe2 composite is then used to construct a biosensor. The new POP/2D MoSe2 nanocomposite offers a high surface-to-volume area and is a good electroactive and biocompatible adsorbent for loading TB probe and capture antibodies. Adsorbed TB onto the POP/2D MoSe2 nanocomposite is utilized as a redox probe for the signal amplification unit. This TB/POP/2D MoSe2 nanocomposite provides good electron transfer properties of TB redox probe, good electrical conductivity, good biocompatibility, and likable adsorption ability, thus obtaining a sufficient immobilization quantity of antibodies for the sensor construction. After immobilization of the anti-AFB1 antibody and blocking with BSA on the composite surface, the immunosensor is obtained for the detection of AFB1. Under optimum conditions, the sensor shows a linear logarithmic range of 2.5-40 ng mL-1 with a limit of detection (LOD) of 0.40 ng mL-1. The developed sensor provides several advantages in terms of simplicity, low cost, short analysis time, high selectivity, stability, and reproducibility. Additionally, the proposed immunosensor is successfully validated by the detection of AFB1 in rice, corn, and peanut samples. Utilizing the TB/POP/2D MoSe2 nanocomposite, this label-free electrochemical immunosensor demonstrates outstanding sensitivity and selectivity in detecting AFB1, making it a valuable tool for ensuring the safety of agricultural products and enhancing food security.

Low-Cost Hydrogen Production from Alkaline/Seawater over a Single-Step Synthesis of Mo3 Se4 -NiSe Core-Shell Nanowire Arrays

The rational design and steering of earth-abundant, efficient, and stable electrocatalysts for hydrogen generation is highly desirable but challenging with catalysts free of platinum group metals (PGMs). Mass production of high-purity hydrogen fuel from seawater electrolysis presents a transformative technology for sustainable alternatives. Here, a heterostructure of molybdenum selenide-nickel selenide (Mo3 Se4 -NiSe) core-shell nanowire arrays constructed on nickel foam by a single-step in situ hydrothermal process is reported. This tiered structure provides improved intrinsic activity and high electrical conductivity for efficient charge transfer and endows excellent hydrogen evolution reaction (HER) activity in alkaline and natural seawater conditions. The Mo3 Se4 -NiSe freestanding electrodes require small overpotentials of 84.4 and 166 mV to reach a current density of 10 mA cm-2 in alkaline and natural seawater electrolytes, respectively. It maintains an impressive balance between electrocatalytic activity and stability. Experimental and theoretical calculations reveal that the Mo3 Se4 -NiSe interface provides abundant active sites for the HER process, which modulate the binding energies of adsorbed species and decrease the energetic barrier, providing a new route to design state-of-the-art, PGM-free catalysts for hydrogen production from alkaline and seawater electrolysis.

Electrospun cobalt-doped 2D-MoSe2/polypyrrole hybrid-based carbon nanofibers as electrochemical sensing platforms

A novel cobalt-doped two-dimensional molybdenum diselenide/polypyrrole hybrid-based carbon nanofiber (Co/MoSe2/PPy@CNF) was prepared using the hydrothermal method followed by electrospinning technique. The structural and morphological properties of the 2D-TMD@CNF-based hybrids were characterized through X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), and transmission electron microscopy (TEM). The Co-MoSe2/PPy@CNF exhibited large surface area, porous structure, and improved active sites due to the synergistic effect of the components. The electrochemical and electrocatalytic characteristics of the 2D-TMD@CNF-modified electrodes were also investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The Co/MoSe2/PPy@CNF electrode was used as an electrochemical sensor for simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) and showed enhanced catalytic activity and sensitivity. Using DPV measurements, the Co/MoSe2/PPy@CNF demonstrated wide linear ranges of 30-3212 μM for AA, 1.2-536 μM for DA, and 10-1071 μM for UA with low detection limits of 6.32, 0.45, and 0.81 μM, respectively. The developed sensor with the Co/MoSe2/PPy@CNF-modified electrode was also applied to a human urine sample and gave recoveries ranging from 94.0 to 105.5% (n = 3) for AA, DA, and UA. Furthermore, the Co/MoSe2/PPy@CNF-based sensor exhibited good selectivity and reproducibility for the detection of AA, DA, and UA.

Facile Synthesis of Microsphere-like Co0.85Se Structures on Nickel Foam for a Highly Efficient Hydrogen Evolution Reaction

Microsphere-shaped cobalt selenide (Co0.85Se) structures were efficiently synthesized via a two-step hydrothermal process. Initially, cobalt hydroxide fluoride (Co(OH)F) microcrystals were prepared using a hydrothermal method. Subsequently, Co0.85Se microsphere-like structures were obtained through selenization. Compared to Co(OH)F, the microsphere-like Co0.85Se structure exhibited outstanding catalytic activity for the hydrogen evolution reaction (HER) in a 1.0 M KOH solution. Electrocatalytic experiments demonstrated an exceptional HER performance by the Co0.85Se microspheres, characterized by a low overpotential of 148 mV and a Tafel slope of 55.7 mV dec-1. Furthermore, the Co0.85Se electrocatalyst displayed remarkable long-term stability, maintaining its activity for over 24 h. This remarkable performance is attributed to the excellent electrical conductivity of selenides and the highly electroactive sites present in the Co0.85Se structure compared to Co(OH)F, emphasizing its promise for advanced electrocatalytic applications.

Cobalt selenide with ordered cation vacancies for efficient oxygen reduction and frigostable Al-air batteries

Aluminum-air batteries are still inhibited by the sluggish cathodic oxygen reduction reactions, especially in low temperature conditions. Thus, it is urgent to develop efficient electrocatalysts for Al-air batteries to allow their use in extreme weather conditions. In this work, hexagonal Co0.85Se-decorated N,Se co-doped carbon nanofibers (Co0.85Se@N,Se-CNFs) were synthesized via facile carbonization/selenization of electrospun ZIF-67 nanocubes. The as-prepared metallic Co0.85Se with ordered structural cation vacancies endows Co0.85Se@N,Se-CNFs with remarkable oxygen reduction reaction activity, including high onset and half-wave potentials (0.93 V and 0.87 V vs. RHE, respectively). Consequently, the corresponding Al-air battery exhibits superior performance in a wide range of operating temperatures (-40-50 °C). For instance, this Al-air battery exhibits a voltage from 0.15-1.2 V with a peak power density of about 0.7 mW cm-2 at -40 °C. It is expected that TMSe-decorated N,Se co-doped carbon nanofibers could be applied in extensive energy fields.

Improving Catalytic Activity of "Janus" MoSSe Based on Surface Interface Regulation

The monolayer Janus MoSSe is considered to be a promising catalytic material due to its unique asymmetric structure. In order to improve its catalytic performance for hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs), many attempts have been made. In this work, a series of transition metal (TM) atoms were anchored on the Janus MoSSe surface to screen effective TM single-atom catalysts for HERs and OERs through density functional theory (DFT) calculations. Fe@MoSSe presents excellent HERs performance and Ni@MoSSe presents excellent catalytic performance for OERs with extremely low over-potential of 0.32 V. The enhanced activity is attributed to the modest energy level of the d band center of the transition metal atom, and the transition metal atom improves the conductivity of the original MoSSe and offers unoccupied states near the Fermi level. At the same time, the anchoring of transition metal atoms redistributes the charge in the MoSSe system, which effectively regulates the electronic structure of the material itself. The strain calculation shows that the activity of the catalyst can be improved by reasonably adjusting the value of the applied strain.

Superionic conductor Ag2Se modulated CoSe2 nanosheets prepared via monometallic cation release for efficient pH-universal water electrolysis into hydrogen

Superionic conductors regulated transition metal chalcogenides are the newly emerged electrocatalyst in water electrolysis into clean hydrogen and oxygen. However, there is still much room for the development of structural design, electronic modulation and heterogeneous interface construction to improve the overall water splitting performance in pH-universal solutions, especially in alkaline and neutral mediums. Herein, using β-cyclodextrin (β-CD) and citric acid (CA) organics with abundant hydroxyl (-OH) and carboxyl (-COOH), a special Ag₂Se nanoparticles-decorated CoSe₂ flower-like nanosheets loaded on porous and conductive nickel foam substrate (Ag₂Se-CoSe₂/NF) was successfully constructed by a new method of monometallic cation release of coordinated cobalt. The Ag₂Se phase exerts the nature characteristics of superionic conductors to modulate the morphological and electronic structures of CoSe₂ as well as improve its conductivity. The generated rich active interfaces and abundant Se vacancy defects facilitate numerous active sites exposure to accelerate the hydrogen ion transport and charge transfer. Compared to the single-phase Ag₂Se/NF-8 and CoSe₂/NF, the prepared Ag₂Se-CoSe₂/NF-8 with a two-phase synergistic effect achieves an outstanding pH-universal electrocatalytic hydrogen production performance by water electrolysis, as evidenced by a lower overpotential (60 mV, 212 mV and 85 mV vs RHE at 10 mA cm^-2 for pH = 0.36, 7.00 and 13.70, respectively). Only a voltage of 1.55 V at 10 mA cm^-2 is required to implement the overall water splitting in an alkaline electrolyzer. This work provides significant guidance for the future designation and practical development of transition metal chalcogenides with superionic conductors applied in the electrocatalytic field.

Synergistic 2D MoSe2@WSe2 nanohybrid heterostructure toward superior hydrogen evolution and flexible supercapacitor

Two-dimensional (2D) transition metal dichalcogenide (TMDC) heterostructure is a new age strategy to achieve high electrocatalytic activity and ion storage capacity. The less complex and cost-effective applicability of the large-area TMDC heterostructure (HS) for energy applications require more research. Herein, we report the MoSe₂@WSe₂ nanohybrid HS electrocatalyst prepared using liquid exfoliated nanocrystals, followed by direct electrophoretic deposition (EPD). The improved catalytic activity is attributed to the exposure of catalytic active sites on the edge of nanocrystals after liquid exfoliation and the synergistic effect arises at HS interfaces between the MoSe₂ and WSe₂ nanocrystals. As predicted, the HS catalyst achieves a lower overpotential of 158 mV, a smaller Tafel slope of 46 mV dec^-1 for a current density of 10 mA cm^-2, and is stable for a long time. The flexible symmetric supercapacitor (FSSC) based on the HS catalyst demonstrates the excellent specific capacitance (C_sp) of 401 F g^-1 at 1 A g^-1, 97.20% capacitance retention after 5000 cycles and high flexible stability over 1000 bending cycles. This work presents a less complex and solution-processed efficient catalyst for future electrochemical energy applications.

Critical Review, Recent Updates on Zeolitic Imidazolate Framework-67 (ZIF-67) and Its Derivatives for Electrochemical Water Splitting

Design and construction of low-cost electrocatalysts with high catalytic activity and long-term stability is a challenging task in the field of catalysis. Metal-organic frameworks (MOF) are promising candidates as precursor materials in the development of highly efficient electrocatalysts for energy conversion and storage applications. This review starts with a summary of basic concepts and key evaluation parameters involved in the electrochemical water-splitting reaction. Then, different synthesis approaches reported for the cobalt-based Zeolitic imidazolate framework (ZIF-67) and its derivatives are critically reviewed. Additionally, several strategies employed to enhance the electrocatalytic activity and stability of ZIF-67-based electrocatalysts are discussed in detail. The present review provides a succinct insight into the ZIF-67 and its derivatives (oxides, hydroxides, sulfides, selenides, phosphide, nitrides, telluride, heteroatom/metal-doped carbon, noble metal-supported ZIF-67 derivatives) reported for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and overall water splitting applications. Finally, this review concludes with the associated challenges and the perspectives on developing the best economic, durable electrocatalytic materials.

Electronic wastes: A near inexhaustible and an unimaginably wealthy resource for water splitting electrocatalysts

E-wastes comprise complex combinations of potentially toxic elements that cause detrimental effects of the environmental contamination; besides their posing threat, most of the products also contain valuable and recoverable materials (Li, Au, Ag, W, Se, Te, etc.), which make them distinct from other forms of industrial wastes. Most of these value-added elements which are primarily employed in electronic goods are disposed of by incineration and land-filling. This is a serious issue besides just environmental pollution, as IUPAC recognized that such ignorance of or poor attention to e-waste recycling has put several elements in the periodic table to the list of endangered elements. Recycling these wastes utilized for electrocatalytic water splitting to produce H₂. These recovered e-wastes materials are used as electrocatalysts for the water-splitting, additives to enhance reaction kinetics, and substrate electrodes as well. Recycling and recovery of value-added materials in the view of applying them to electrocatalytic water splitting with endangered elements' perspective have not been covered by any recent review so far. Hence, this review is dedicated to discussing the opportunities available with recycling e-wastes, types of value-added materials that can be recovered for water splitting, strategies exploited, and prospects are discussed in details.

Single Ir atom anchored in pyrrolic-N4 doped graphene as a promising bifunctional electrocatalyst for the ORR/OER: a computational study

The development of highly-efficient electrocatalysts with bifunctional catalytic activity for oxygen reduction reaction (ORR) and oxygen evolution reaction. (OER) still remains a great challenge for the large-scale application of renewable energy conversion and storage technologies. Herein, by means of comprehensive density functional theory (DFT) computations, we systematically explored the potential of pyrrolic-N doped graphene (pyrrolic-N₄-G) supported various transition metal atoms (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Pd, W, Os, Ir, and Pt) as electrocatalysts for the ORR and OER. Our results revealed that these TM/pyrrolic-N₄-G candidates exhibit high electrochemical stability due to their positive dissolution potentials. Especially, the Ir/pyrrolic-N₄-G can perform as a promising bifunctional electrocatalyst for both ORR and OER with the low overpotentials (η^ORR = 0.34 V and η^OER = 0.32 V). Interestingly, multiple-level descriptors, including energy descriptor (ΔG_OH* - ΔG_O*), (ΔG_OH*), structure descriptor (φ), and d-band center (ε) can well rationalize the origin of the high catalytic activity of Ir/pyrrolic-N₄-G for the ORR/OER. Our findings not only further enrich the SACs, but also open a new avenue to develop novel 2D materials-based SACs for highly efficient oxygen electrocatalysts.

A study on the high efficiency reduction of p-nitrophenol (4-NP) by a Fe(OH)3/Fe2O3@Au composite catalyst

Precious metal nanometric catalysts are widely used in the removal of harmful substances. In the process of synthesis and catalytic reaction, it is particularly important to study green and simple synthesis methods and high catalytic efficiency. In this paper, a green one-step method was used to synthesize the Fe(OH)₃/Fe₂O₃@Au composite catalyst, in which Au was single atom-dispersed. The removal of 4-nitrophenol (4-NP), a typical dangerous chemical widely existing in factory waste gas, waste water and automobile exhaust gas, was catalysed by Fe(OH)₃/Fe₂O₃@Au. The catalytic performance of Fe(OH)₃/Fe₂O₃@Au with different synthesis conditions (different amounts of MES, NaBH₄, FeSO₄, Au and Pt) on the 4-NP reduction reaction were systematically studied. Finally, the stability and recyclability of Fe(OH)₃/Fe₂O₃@Au composite nanocatalyst were investigated thoroughly.

Interfacial Mo-N-C Bond Endowed Hydrogen Evolution Reaction on MoSe2@N-Doped Carbon Hollow Nanoflowers

Molybdenum diselenide (MoSe₂) has been considered as promising electrocatalysts for catalyzing the hydrogen evolution reaction (HER) due to its narrow band gap and appropriate adsorption free energy. However, its catalytic performance is still impeded by inferior electrical conductivity and insufficient active sites, thus leading to unsatisfactory HER performance. Herein, MoSe₂@N-doped carbon (NC) hollow nanoflowers with interfacial Mo-N-C bonds were controllably fabricated through the in situ selenization of the self-polymerized Mo-polydopamine precursor. Benefiting from the unique hollow structure, NC protective layer, and intimate interfacial interaction, the optimal MoSe₂@NC displays good HER performance with low overpotentials (175 and 183 mV) and long-term stability (up to 12 h at -10 mA cm^-2) in 0.5 M H₂SO₄ and 1.0 M KOH solutions, respectively. The theoretical results show that Mo-N-C bonds at the interface of MoSe₂@NC give rise to relatively low unoccupied e_g orbital density of states and ideal H₂ adsorption free energy. This work presented here highlights the critical role of interfacial chemical bonds in regulating the electronic structure of nanomaterials and further improving the HER performance.

2D coordination polymer-derived CoSe2-NiSe2/CN nanosheets: the dual-phase synergistic effect and ultrathin structure to enhance the hydrogen evolution reaction

The evolution of cost-effective hydrogen evolution reaction (HER) electrocatalysts is of great significance for the development of clean energy. Exploring effective synthesis strategies to optimize the performance of non-noble metal electrocatalysts has always attracted our attention. Herein, ultrathin coordination polymers were used as precursors to controllably synthesize two-dimensional (2D) ultrathin dual-phase transition metal selenide (TMSs)/carbon-nitrogen (CN) composites (CoSe2-NiSe2/CN) by a two-step method (first a low temperature hydrothermal method for selenization, and then high temperature calcination selenization). Benefiting from its large specific surface area (49 m2 g-1), abundant catalytically active sites and synergistic effects, CoSe2-NiSe2/CN can significantly enhance the HER catalytic activity and exhibits good electrocatalytic activity with an overpotential of 150 mV at -10 mA cm-2, and a small Tafel slope of 42 mV dec-1 in an acidic electrolyte for the HER. This work provides a new strategy for optimizing the HER catalytic activity of TMSs by preparing 2D ultrathin dual-phase TMS composite materials.

1 T-MoSe2 monolayer supported single Pd atom as a highly-efficient bifunctional catalyst for ORR/OER

The development of highly-efficient catalysts for oxygen reduction reaction (ORR) or oxygen evolution reaction (OER) is highly crucial for the commercial applications of some novel energy-related devices. Herein, using comprehensive first-principles computations, the potential of a variety of single metal-based catalysts supported by MoSe₂ nanosheet to boost the ORR or OER process was evaluated. The computations revealed that these considered metal atoms can be more stably anchored on 1 T-MoSe₂ than those of on 2H-MoSe₂. In particular, the supported Ni and Pd catalysts on 1 T-MoSe₂ exhibit high OER activity due to their quite low overpotential (0.47 and 0.49 V). Meanwhile, the anchored Pd atom on 1 T-MoSe₂ also displays excellent ORR performance with an ultra-low overpotential of 0.32 V, thus implying its superior bifunctional activity for ORR/OER. Our results provide a quite promising avenue to design a new class of MoSe₂-based single atom catalysts for fuel cells, which also further enriches the application fields of MoSe₂ nanosheets in advanced catalysis.

Synthesis of Ultrathin and Grid-Structural Carbon Nanosheets Coupled with Mo2 C for Electrocatalytic Hydrogen Production

Molybdenum carbide possessing a Pt-like d-band electronic structure is considered as one of potential candidates of electrocatalysts and it shows intrinsic catalytic property. However, a high carbonizing temperature easily leads to the coalescence of nanoparticles (NPs). Here, we propose a simple sol-gel route to achieve high dispersity of carbide NPs by designing a Mo-involved xerogel. The results show that molybdenum carbide NPs are dispersed and anchored on the nitrogen-doped carbon nanosheets (Mo₂ C@NC). Ultrathin carbon layers resemble graphene and the network structures act as a support of carbide NPs, which can hinder NPs' coalescence effectively. Nanpoparticles cross-coupled on network-structure nanosheets display the grid shapes. Electrochemical studies indicate that Mo₂ C@NC material exhibits outstanding hydrogen evolution performance in alkaline electrolyte.

Transition Metal Chalcogenides as a Versatile and Tunable Platform for Catalytic CO2 and N2 Electroreduction

Group VI transition metal chalcogenides are the subject of increasing research interest for various electrochemical applications such as low-temperature water electrolysis, batteries, and supercapacitors due to their high activity, chemical stability, and the strong correlation between structure and electrochemical properties. Particularly appealing is their utilization as electrocatalysts for the synthesis of energy vectors and value-added chemicals such as C-based chemicals from the CO₂ reduction reaction (CO₂R) or ammonia from the nitrogen fixation reaction (NRR). This review discusses the role of structural and electronic properties of transition metal chalcogenides in enhancing selectivity and activity toward these two key reduction reactions. First, we discuss the morphological and electronic structure of these compounds, outlining design strategies to control and fine-tune them. Then, we discuss the role of the active sites and the strategies developed to enhance the activity of transition metal chalcogenide-based catalysts in the framework of CO₂R and NRR against the parasitic hydrogen evolution reaction (HER); leveraging on the design rules applied for HER applications, we discuss their future perspective for the applications in CO₂R and NRR. For these two reactions, we comprehensively review recent progress in unveiling reaction mechanisms at different sites and the most effective strategies for fabricating catalysts that, by exploiting the structural and electronic peculiarities of transition metal chalcogenides, can outperform many metallic compounds. Transition metal chalcogenides outperform state-of-the-art catalysts for CO₂ to CO reduction in ionic liquids due to the favorable CO₂ adsorption on the metal edge sites, whereas the basal sites, due to their conformation, represent an appealing design space for reduction of CO₂ to complex carbon products. For the NRR instead, the resemblance of transition metal chalcogenides to the active centers of nitrogenase enzymes represents a powerful nature-mimicking approach for the design of catalysts with enhanced performance, although strategies to hinder the HER must be integrated in the catalytic architecture.

Gd doped molybdenum selenide/carbon nanofibers: an excellent electrocatalyst for monitoring endogenous H2S

Design and synthesis of Gd doped molybdenum selenide/carbon nanofibers for monitoring H₂S.

Recent progress in transition metal selenide electrocatalysts for water splitting

The urgent demand of scalable hydrogen production has motivated substantial research on low cost, efficient and robust catalysts for water electrolysis. In order to replace noble metals and their derivatives, transition metal (Fe, Co, Ni, Mo, Cu, etc.) selenides have demonstrated promising catalysis on both hydrogen and oxygen evolutions. Very recently, a number of reports have presented a variety of approaches to enhance their electrocatalytic activity. This review summarizes the most recent progress in transition metal selenide electrocatalysts for HER, OER, and overall water splitting. The merits and limitations of metal selenides are also discussed in the aspects of structure and composition. Moreover, we highlight new strategies and future challenges for design and synthesis of high performance electrocatalysts.