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Based on the experimentally reported stable and conductive two-dimensional covalent organic frameworks with copper phthalocyanine (CuPc) as building block and cyan substituted phenyl as connector (CuCOF-CN) as an electrocatalyst for CO2 reduction reaction (RR), first principle calculations were performed on CuCOF-CN and its analog with the CN being replaced by H (CuCOF). Comparatively studied on the crystal structures, electronic properties, and CO2RR performance of the two catalysts found that CuCOF has reduced crystal unit size, more positive charge on Cu and CuPc segments, smaller band gap, and lower reaction barrier for CO2 RR than CuCOF-CN. CuCOF is proposed to be good potential electrocatalyst with good environment friendliness. The substituent effect and structure-property-performance relationship would help for designing and fabricating new electrocatalysts. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting for green hydrogen production necessitates effective electrocatalysts. Currently, commercial catalysts are primarily platinum-based. Therefore, finding catalysts with comparable catalytic activity but lower cost is essential. This paper describes spinel-structured catalysts containing nickel cobaltite NiCo2O4, graphene, and additionally doped with heteroatoms. The structure and elemental composition of the obtained materials were analyzed by research methods such as TEM, SEM-EDX, XRD, XPS, and Raman spectroscopy. The electrochemical measurements showed that hybrid materials containing nickel cobaltite NiCo2O4 doped with graphene are highly active catalysts in the hydrogen evolution reaction (Tafel slopes = 91 mV dec−1, overpotential = 468 mV and onset potential = -339 mV), while in the oxygen evolution reaction (Tafel slopes = 51 mV dec−1, overpotential = 1752 mV and onset potential = 370 mV), bare NiCo2O4 without the addition of carbon has a worse activity (for HER: Tafel slopes = 120 mV dec−1, overpotential - does not achieve and onset potential = -404 mV, for OER: Tafel slopes = 54 mV dec−1, overpotential = 1796 mV and onset potential = 410 mV). In terms of stability, comparable results were obtained for each synthesized compound for both the HER and OER reactions. [ABSTRACT FROM AUTHOR]

Developing cutting-edge catalysts for oxygen evolution reaction (OER) is crucial for enhancing the efficiency of water splitting. Spinel-type materials have gained recognition for their exceptional catalytic performance in OER activity. The excessive OER overpotential is the significant obstacle that hinders the use of spinel-type materials. In this work, polyaniline (PANI) was incorporated to significantly enhance the performance of spinel SnFe2O4 material by straightforward hydrothermal method. SnFe2O4@PANI catalyst demonstrated an impressive overpotential of 198 mV at 10 mA cm–2 and a 33 mV dec–1 Tafel slope with higher OER activity. The electrochemical surface area (ECSA) of SnFe2O4@PANI catalyst was determined to be 2348.53 cm2, with higher cyclic stability of 25 h after 5000th cycles with minimal impedance characteristics (Rct = 0.18 Ω). In addition, the findings showed that the inclusion of PANI led to expansion of the surface area to improve the conductivity, resulting in notable enhancement of the catalysts' OER activity. This modification has resulted in an improved OER catalyst, making it highly sought after for various applications in the water-splitting field. Highlights: SnFe2O4@PANI catalyst was synthesized through hydrothermal route for improved OER activity. The SnFe2O4@PANI catalyst displays a reduced overpotential of 198 mV and Tafel slope of 33 mVdec−1. SnFe2O4@PANI catalyst demonstrates remarkable cycling stability of 25 h. SnFe2O4@PANI catalyst exhibits significantly lower impedance of Rct = 0.18 Ω. [ABSTRACT FROM AUTHOR]

Hydrogen production from water splitting is considered the most environment-friendly and sustainable method to acquire energy. Alkaline water electrolysis has been widely employed for hydrogen production, but it is still challenging to prepare non-precious metals electrocatalysts to replace the noble-metal-based catalysts. Here we proposed electroless method to prepare a NiCoP nanocrystalline thin flim as efficient electrocatalysts. The morphology and mechanisms of the 45-minute alloy films deposited on Cu substrate were characterized by SEM, XRD, and XPS techniques, moreover, LSV, EIS, and CP were applied to analyze the electrochemical behavior. The nanocrystalline NiCoP45min alloy exhibits higher hydrogen evolution reaction (HER) activity than platinum sheet. An overpotential of -98 mV and a Tafel slope of 47.94 mV·dec−1 at 10 mA·cm−2 was achieved with the catalyst during HER in an alkaline medium. Additionally, its excellent catalytic activity is confirmed by a low Rt value 2.48 Ω. Remarkably, this catalyst also exhibits high HER stability for about 45 h in an alkaline electrolysic solution. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The development of high-performance and low-cost bifunctional electrocatalysts is crucial for industrial-scale hydrogen production through water electrolysis. In this study, bimetallic FexCo1−xP nanosheet array electrocatalyst was prepared successfully by a hydrothermal method on the three-dimensional porous nickel foam substrate, which not only retains the excellent HER performance of CoP, but also effectively reduces the activation energy barrier during the OER process by incorporating Fe. This composite structure adjusts the local electronic structure, thereby enhancing the adsorption capacity of reaction intermediates at the active sites. Consequently, the nanosheet-like FexCo1−xP electrocatalyst without noble metal doping exhibits outstanding catalytic performance. Specifically, at the current density of 20 mA·cm− 2 in 1.0 M KOH electrolyte, the overpotentials of Fe0.2Co0.8P nanosheet for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are significantly lower than those of most electrocatalysts, measuring 162 mV and 234 mV, respectively. The results demonstrate the synergistic effect among the Fe, Co, and P elements, which facilitate the electrocatalytic process. Moreover, the synthesized Fe0.2Co0.8P nanosheet array electrocatalyst possesses a large active surface area and good conductivity, effectively promoting the kinetics of the electrocatalytic reactions. This work provides an effective approach for synthesizing efficient and inexpensive bifunctional electrocatalysts. [ABSTRACT FROM AUTHOR]

MXenes are a class of two-layered progress metal carbides/nitrides that offer unique properties for diverse applications, including electrocatalysis, supercapacitors, biosensors, water refinement, and many more. Here, we demonstrate a novel MXene@Bi2O3 heterostructure with boosted electrocatalytic activity for OER. Furthermore, pictures captured by electron microscopy demonstrated MXene's strong cooperation with Bi2O3. Additionally, the 2D MXene cooperation created extra pathways for mass transport during OER. Distinctive structure and the synergistic interaction between its components, MXene@Bi2O3 demonstrates remarkable electrocatalytic activity and durability in alkaline environments. With constant current density of 10 mAcm–2, the MXene@Bi2O3 catalyst showed outstanding catalytic activity and an overpotential of around 278 mV, which is 85 mV lower than the pure Bi2O3 catalyst. Combining Ti3C2Tx MXene with Bi2O3 led to increased intrinsic activity and accelerated charge transfer kinetics. This study proposes an effective approach for creating metal oxides and MXene hybrids with distinctive structures for electrocatalytic water splitting. The composite's exceptional electrochemical activity and durability suggest its potential as a very efficient electrocatalyst for water-splitting. Furthermore, this work's design and synthesis of hybrid composites with MXene-based nanomaterials opens up new opportunities for developing novel and efficient electrocatalysts in electrochemical applications. [ABSTRACT FROM AUTHOR]

Platinum-group metal ruthenium (Ru) is considered an ideal substitute for platinum (Pt) in the hydrogen evolution reaction (HER) due to its excellent electrocatalytic performance and cost that is 20 times lower than Pt. Herein, we prepared Ru-doped WO3 nanosheets array on carbon cloth (CC) using the hydrothermal method, followed by successful high-temperature nitridation to obtain Ru-WN/CC nanoarray electrocatalysts. As prepared Ru-doped WN nanosheets exhibit a highly porous structure, providing abundant active sites for HER. Electrochemical performance tests demonstrate that compared to pristine WN/CC, 7% Ru-WN/CC exhibits a reduced overpotential of 94 mV at a current density of 10 mA cm-2, with a Tafel slope of only 51.4 mV dec-1 and an Rct of 6.08 Ω. Moreover, it maintains high catalytic activity for at least 24 hours under acidic conditions. The superior electrocatalytic activity of Ru-WN/CC is attributed to the significant acceleration of the kinetic rate of WN electrocatalysts by Ru doping, the reduction of electronic transfer resistance in WN, and the enlargement of the electrochemically active surface area of WN. This study provides an important reference for the development of novel low noble metal-doped electrocatalytic materials and has guiding significance for the application of metal nitrides in water splitting for hydrogen production. [ABSTRACT FROM AUTHOR]

The design of low-cost and high-performance anodic electrocatalyst is essential in proton exchange membrane water electrolysis (PEMWE) application. Herein, we design and synthesize a core–shell structure with Ir-rich shell and AuIr alloy core by using a simple liquid phase reduction method, which exposed a large number of active sites. The d-band center of Ir active sites, merely 2 nm in size, was shifted by the electronegativity difference between the Au and Ir atoms at the core–shell interface. The strong electronic effect can inhibit the dissolution and corrosion of Ir active sites under acidic and high potential conditions. As a result, Irx@Au0.25Ir0.75−x catalyst shows merely 235 mV overpotential at the current density of 10 mA cm−2, 75 mV lower than the commercial Ir black catalyst, and 2.6-fold higher mass activity than the commercial Ir black catalyst. Furthermore, when Irx@Au0.25Ir0.75−x was used as the anionic catalyst, the electrolysis voltage at 1 A cm−2 is 1.7 V in PEMWE, and this activity was maintained for more than 100 h and had exhibited excellent stability, indicating its ideal prospects as an electrocatalyst. AuIr alloy with Ir-rich core and AuIr alloy shell exposed numerous active sites and improved the utilization efficiency of electrocatalyst. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The preparation of highly active, rare earth, non-platinum-based catalysts for hydrogen evolution reactions (HER) in alkaline solutions would be useful in realizing green hydrogen production technology. Perovskite oxides are generally regarded as low-active HER catalysts, owing to their unsuitable hydrogen adsorption and water dissociation. In this article, we report on the synthesis of Li2ZrO3 perovskites substituted with samarium and terbium cations at A-sites for the HER. LSmZrO3 (LSmZO) and LTbZrO3 (LTbZO) perovskite oxides are more affordable materials, starting materials in abundance, environmentally friendly due to reduced usage of precious metal and moreover have potential for several sustainable synthesis methods compared to commercial Pt/C. The surface and elemental composition of the prepared materials have been confirmed by X-ray photoelectron spectroscopy (XPS). The morphology and composition analyses of the LSmZO and LTbZO catalysts showed spherical and regular particles, respectively. The electrochemical measurements were used to study the catalytic performance of the prepared catalyst for hydrogen evolution reactions in an alkaline solution. LTbZO generated 2.52 mmol/g/h hydrogen, whereas LSmZO produced 3.34 mmol/g/h hydrogen using chronoamperometry. This was supported by the fact that the HER electrocatalysts exhibited a Tafel slope of less than 120 mV/dec in a 1.0 M alkaline solution. A current density of 10 mA/cm2 is achieved at a potential of less than 505 mV. The hydrogen production rate of LTbZO was only 58.55%, whereas LSmZO had a higher Faradaic efficiency of 97.65%. The EIS results demonstrated that HER was highly beneficial to both electrocatalysts due to the relatively small charge transfer resistance and higher capacitance values. [ABSTRACT FROM AUTHOR]

In this article, we have studied the influence of the heat treatment in an inert atmosphere on the structure and catalytic activity of the PtCu/C catalysts with an architecture of bimetallic nanoparticles obtained by a multi-step synthesis method. The transformation of the structure obtained by a multi-step synthesis method into a solid solution during the heat treatment at 350 °C has been shown by the methods of high-resolution TEM and XPS. It has been found that regardless of the type of a carbon support used, the heat treatment leads to an increase in the specific mass activity by 1.4–1.6 times. The increase in the catalytic activity after the heat treatment is achieved due to a change in the chemical composition of the surface and an increase in the degree of alloying of metal components. Due to the combination of the heat treatment and the use of a nitrogen-doped carbon support, we have succeeded in obtaining the PtCu/C catalyst, the ORR activity of which is 6.4 times higher than that of the commercial analog. Testing of the most promising samples as part of the MEA has confirmed the high quality of the materials obtained, the maximum power being 696 W/g (Pt) for the PtCu/C catalyst after the heat treatment. [ABSTRACT FROM AUTHOR]

The electrochemical water splitting to produce hydrogen converts electric energy into clean hydrogen energy, which is a groundbreaking concept of energy optimization. To achieve high efficiency, numerous strategies have been developed to enhance the performance of electrocatalysts. Among these, interface engineering with molecules/ions/groups, serves as a versatile approach for optimizing the performance of electrocatalysts in water splitting. On the basis of numerous achievements in high-performance electrocatalysts engineered through molecules/ions/groups at interface, a comprehensive understanding of these advancements is crucial for guiding future progress. Herein, after providing a concise overview of the background, the interface engineering via molecules/ions/groups for electrocatalytic water splitting is demonstrated from three perspectives. Firstly, the engineering of electronic state of electrocatalysts by molecules/ions/groups at interface to reduce the Gibbs free energy of the corresponding reactions. Secondly, the modification of local microenvironment surrounding electrocatalysts via molecules/ions/groups at interface to enhance the transfer of reactants and products. Thirdly, the protection of electrocatalysts with molecule/ion/group fences improves their durability, including protecting active sites from leaching and defending them against harmful species. The fundamental principles of these three aspects are outlined for each, along with pertinent comments. Finally, several research directions and challenges are proposed. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) plays an important role in the field of renewable energy conversion. It is imminent to develop a highly active, inexpensive and easily available electrocatalyst. Here, we used hydrothermal method and calcination process to combine graphene aerogel with cobalt-copper-based oxide, and obtained two kinds of composite aerogel materials (CuCo2O4/GA) with different (needle spherical and sheet spherical) nanoarray morphology for catalyzing the oxygen evolution reaction. Compared with commercial catalyst Ir/C (338mV) and sheet spherical nanoarray CuCo2O4/GA (GCA-2) (292 mV), the needle spherical nanoarray CuCo2O4/GA (GCA-1) exhibits a lower overpotential (269 mV) to drive a current density of 10 mA/cm2. At the same time, the Tafel slope of CGA-1 (87 mV dec−1) is similar to Ir/C (88 mV dec−1) and has the best kinetics of oxygen evolution reaction. Moreover, both the needle and sheet spherical nanoarray CuCo2O4/GA have excellent durability of 8 h. The optimized nanoarray CuCo2O4/GA has excellent electrocatalytic activity due to the successful combination of graphene aerogel substrate and cobalt-copper-based oxide, which together promotes the reversible reaction of the electrode-electrolyte interface during the oxygen evolution reaction. The electron conduction rate is increased, and the accessible reactive sites are increased. This article provides a simple and efficient morphological engineering strategy for designing and exploring electrocatalysts for oxygen evolution reactions. [ABSTRACT FROM AUTHOR]

In this study, we explore the multifaceted applications of poly(methyl acrylate) (PMAc)-based composites, specifically focusing on their use as an efficient electrocatalyst for water splitting and a high-capacity supercapacitor. After a synthesis step, a characterization study (SEM, TEM, XRD, and Raman spectroscopy) was performed, and based on TEM results, a consistent pattern of small, uniform, and narrowly distributed Pd NPs within the range of 5–10 nm was observed. Also, other analyses confirmed the successful synthesis of PMAc-based composites. Through meticulous experimentation, the electrocatalytic performance of Pd/PMAc-graphene-carbon nanotube (Pd/PMAc-g-CNT) composites was evaluated against that of traditional Pd/PMAc catalysts. Tafel slope analysis was conducted to assess the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) efficiencies, where Pd/PMAc-g-CNT composites demonstrated significantly lower Tafel slopes of 274.53 mV dec⁻1 for OER and 389.91 mV dec⁻1 for HER. This indicates a superior electrocatalytic activity, enhancing the water splitting process. Furthermore, the same composite showcased an impressive specific capacitance of 132.3 F g⁻1 at a current density of 0.5 A/g, markedly surpassing the performance of the Pd/PMAc catalyst. This exceptional capacitance underlines its potential as a high-efficiency energy storage material. The novelty of this research lies in the synergistic integration of PMAc with graphene and carbon nanotubes to fabricate a dual-functional material. This composite not only excels in electrochemical catalysis for energy conversion but also demonstrates remarkable energy storage capabilities. The Pd/PMAc-g-CNT composite, therefore, emerges as a promising candidate for advancing supercapacitor technology and the electrocatalytic efficiency of water splitting, highlighting its dual utility in renewable energy systems. [ABSTRACT FROM AUTHOR]

The development of efficient and durable catalysts for the hydrogen evolution reaction (HER) is essential for sustainable energy research. Cobalt sulfides (CoSx) have attracted significant interest as prospective catalysts for the HER owing to their promising catalytic activity and high stability. In this study, CoSx nanocrystals embedded in nitrogen-doped carbon frameworks (NC) are fabricated using a zeolite imidazole framework precursor via a two-step pyrolysis-sulfurization process, followed by combination with carbon black (CB) to create CoSx-NC/CB as an efficient electrocatalyst for the HER. Interestingly, this catalyst displays a higher HER activity than that of the investigated materials, with an overpotential of 282 mV at a current density of 10 mA cm− 2, along with a Tafel slope of 57.6 mV dec− 1 in an acidic solution. This performance is attributed to the synergistic effect of CoSx nanoparticles, nitrogen-doped carbon, and highly conductive CB, which improves the number of active sites, electron transfer, and electrochemical surface area. This outcome has significant potential for the development of economically viable catalysts for water splitting. [ABSTRACT FROM AUTHOR]

CoSe is one of the chalcogenides attracting much attention due to its excellent hydrogen evolution reaction (HER) activity and low price. However, CoSe prepared by electrodeposition generally shows lower HER activity and stability under acidic conditions than those prepared by other methods. In this study, it was assumed that the cause of the low HER performance of electrodeposited CoSe is mainly due to the dissolution of Co and Se, which do not form a stable alloy, and annealing of electrodeposited CoSe was introduced to demonstrate this. We compared the HER activity and stability of non-annealed and annealed CoSe in 0.5 M H2SO4 electrolyte and investigated the dissolution behaviors of the two catalysts during HER. As a result, it was found that Co and Se, which did not form a stoichiometric CoSe2 alloy, were found to be vulnerable in acidic conditions. The annealing induced additional CoSe2 formation, improving the HER activity and stability of electrodeposited CoSe. The annealed CoSe exhibited an overpotential of 175 mV at 10 mA cm−2, 27 mV lower than that of non-annealed one, and was stable for 48 h at 10 mA cm−2. [ABSTRACT FROM AUTHOR]

Enhancing the performance of ruthenium (Ru)-based electrocatalysts for the alkaline hydrogen evolution reaction (HER) presents a significant challenge. Herein, titanium dioxide nanowire arrays decorated with ruthenium clusters were grown on carbon cloth (Ru-TiO2 NWAs/CC) via a two-step hydrothermal method. The nanowire array structure increases the surface area of the substrate, allowing for more Ru clusters to be decorated, thereby improving catalytic activity. The resulting Ru3–TiO2 NWAs/CC catalyst exhibits prominent HER performance in 1.0 M KOH with overpotentials of 61 at 10 mA cm−2 and a Tafel slope of only 47.4 mV dec−1. Furthermore, it maintains outstanding stability under alkaline conditions for more than 10 h. The Ru clusters decoration enhances the TiO2/CC kinetic, more active sites were exposed on nanowires of the surface and accelerated electron transport, thus reducing the charge transfer barrier. After the electrochemical test, the morphology and structure of Ru3–TiO2/CC remained largely unchanged, and the valence states of the elements remained stable. This work paves the road to exploiting highly active and cost-efficient electrocatalysts for alkaline hydrogen evolution. [ABSTRACT FROM AUTHOR]

Graphene with high-density defects was generated by one-step gaseous detonation method, designated as DG. The DG exhibits a highly hydrogen evolution reaction (HER) performance in terms of its lower onset potential of 223 mV and smaller Tafel slope of 120 mV·dec−1, which are superior to those of commercial counterpart (CG). Furthermore, the value of DG acted as an excellent support of active materials was verified by successfully hybridizing the MoS2 with DG and the improvement of DG on the HER performance of MoS2. This work provides a simple, economical, energy-saving and high yield to prepared DG with highly HER electrocatalytic activity and advantages as an excellent support material, making it of great value in practical applications. [ABSTRACT FROM AUTHOR]

A crucial aspect of an oxygen evolution reaction is the improvement of electrocatalysts in an alkaline solution. Owing to their highly intrinsic activity and porous nature, perovskites (ABO3) served as potential catalysts for OER. Transition-metal-oxides such as SrO2, MnO2, FeO, Co3O4 and NiO are considered potential catalysts for OER; strontium and manganese base oxides are efficient and have low cost. These catalysts have gained massive attention because of their structure, morphology and polyvalency. Herein, the crystalline perovskite SrMnO3-rGO was fabricated using the hydrothermal method and analyzed using different physical and electrochemical characterizations. Different physical techniques were applied to study crystal structure, morphology and lattice vibration. The scanning electron microscopic analysis confirmed the homogeneous and small-sized structure of pristine SrMnO3 and SrMnO3-rGO composite. Moreover, composite showed a greater surface area (68 m2 g−1) according to the Brunauer Emmett Teller analysis. Then, the developed material was observed to determine stability, Tafel slope and overpotential. Further, the electrochemical characteristics of nickel foam (NF) are also analyzed which displays an overpotential of 378 mV and a Tafel value (80 mV dec−1). In comparison, the prepared SrMnO3-rGO composite showed an overpotential (198 mV) at standard current density (10 mA cm−2) and Tafel plot (37 mV dec−1) with higher durability (30 hours) at 4000th CV cycles. EIS was used to analyze the material's resistance, which showed minimum Rct (0.3 Ω) for composite. The present study expands perovskite-oxides with rGO performance as a catalyst, making it highly efficient for OER electrocatalysts. It can be applied at an industrial scale in the future. Highlights: The SrMnO3-rGO was fabricated by hydrothermal method. Fabricated material was analyzed by various physical and electrochemical techniques. SrMnO3-rGO composite shown a low overpotential (198 mV) and a small Tafel slope (37 mV dec−1) at current density (10 mA cm−2). The composite shown minimum Rct by EIS analysis. SrMnO3-rGO demonstrated the greater stability as evaluated by chronoamperometry. [ABSTRACT FROM AUTHOR]

Developing effective and durable electrocatalysts for long-term energy conversion technologies is still an ongoing problem for researchers. For this purpose, perovskite oxides have attracted significant interest as effective electrocatalysts for oxygen evolution reactions (OER) in response to their highly adjustable catalytic and electrical properties associated with their compositions. This study presents a novel hydrothermal approach to fabricate SrSnO3/rGO composite in order to accelerate the four electron transfer mechanisms. Moreover, the physical analyses show that cubic-shaped SrSnO3 are irregularly dispersed in the form of spherical on the nanosheets of rGO. Compared with pristine, the BET study shows that composite exhibits a greater surface area (59 m2 g−1). To evaluate the catalytic kinetics, conductivity and stability, the electrochemical evaluation of the electrode material (SrSnO3/rGO) was performed in alkaline media with Ni foam (NF) as substrate. The exceptional electrocatalytic performance of the material in the OER could be associated with its unique structure, many active sites, and favorable conductivity. This performance is characterized by fast reaction rates, as indicated by a minimal Tafel constant (33 mV dec−1) along with reduced overpotential (199 mV) at 10 mA cm−2. Moreover, the chronoamperometry (CA) investigation of the SrSnO3/rGO composite indicates 35 h of long-term stability. This study presents a viable approach for producing high-performing perovskite composites for effective OER electrocatalysis. Highlights: The facile SrSnO3/rGO nanocomposite was synthesized using a hydrothermal technique. The physical analysis revealed that SrSnO3/rGO nanocomposite exhibit 59 m2 g−1 surface area. The electrochemical results confirmed the fabrication of SrSnO3/rGO nanocomposite with low overpotential (199 mV) and Tafel slope (33 mV dec−1) at a Current density (Cd) 10 mA cm−2. Chronoamperometry study shows that nanocomposite is highly stable for 35 h. [ABSTRACT FROM AUTHOR]

Investigating efficient electrocatalysts for the oxygen evolution reaction (OER) is an essential aspect of numerous energy revolution systems that involve water electrolysis. Spinel structure has garnered substantial interest as OER catalysts due to their abundance in the Earth, and ability to adjust electronic properties. As the doping plays a decisive role in fine-tuning the structure and controlling size, ultimately enhancing intrinsic activities. Herin, the performance of spinel SnMn2O4 was significantly improved by incorporating Sm doping during the synthesis process, which was done using a cost-effective and efficient hydrothermal method. Nano-flakes morphology exhibited higher surface area which provide higher number of active sites. Sm-doped SnMn2O4 catalyst showed a remarkable over potential of 212 mV at 10 mA cm−2 and a Tafel slope of 37 mV dec–1. Sm-doped SnMn2O4 catalyst exhibited exceptional stability after 5000th cycle and less impedance characteristics. Moreover, results indicated that the addition of Sm dopant caused an increase in surface area and conductivity with significant development in OER activity of catalysts. This study offers enhanced OER catalysts with a broader perspective on the relation between the structure and activity of spinel for more effective energy generation devices for real-life applications. [ABSTRACT FROM AUTHOR]

The production and use green hydrogen fuel is attracted significantly in recent years owing to its high energy density and zero carbon emission. In this paper, Fe2V4O13 nanoparticles of size 22 nm are coated on the nickel foam substrate and this modified electrode is used as electrode towards the electrocatalysis of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolyte. The Fe2V4O13 nanoparticles exhibit high electrochemical active surface area of 2652 cm− 2 which is about ~ 2 and ~ 100 times higher than that of RuO2 (1302 cm− 2) and bare nickel foam (22.5 cm− 2). The observed high electrochemical active surface area for Fe2V4O13 nanoparticles results in enhanced OER and HER performance where it requires an overpotentials of 310 mV in OER and − 181 mV in HER to deliver the high current density of 100 mA cm− 2. The electrochemical activity of the proposed Fe2V4O13 nanoparticles evidenced as a competitive electrocatalyst for both OER and HER. [ABSTRACT FROM AUTHOR]

Nowadays, due to the increase in the diversity and extent of environmental pollutants compared to before, the need for high-performance multifunctional semiconductors is felt more than ever to reduce costs and remove several different environmental pollutants at the same time. In the present research, the positive-copper oxide (p-CuO)/negative-zinc titanate (n-ZnTiO3) as a novel multifunctional heterojunction semiconductor with photocatalytic, electrocatalytic, and antimicrobial capabilities to remove several different environmental pollutants such as rhodamine B (RhB) and methylene blue (MB) organic dyes, 4-chlorophenol antibiotic, and Escherichia coli and Staphylococcus aureus bacteria was synthesized. The crystal phase, morphology and particle size, and particle distribution were analyzed by XRD, FT-IR, Raman, SEM, and EDX/Map analyses. In addition, photocatalytic activity and surface porosity of p-copper oxide/n-zinc titanate semiconductor was analyzed by UV–visible, DRS, and BET devices. The UV–visible analysis indicated a photodegradation yield of 66.67 and 57.14% for rhodamine B (RhB) and methylene blue (MB) dye, respectively, in the presence of light irradiation in optimum experiment conditions of pH:7, temperature: 65 °C, mixing speed: 200 rpm, retention time: 5 h, p-copper oxide/n-zinc titanate value; 1 g/l, dyes value; 10 mg/l and distance between the irradiation source and solution surface: 10 cm. Electrocatalytic activity of p-copper oxide/n-zinc titanate semiconductor for degradation of 4-chlorophenol pollutant with a concentration of 0.0001 M was evaluated by cyclic voltammetry (CV) device in optimal conditions of N-icosane binder percentage: 5%, p-copper oxide/n-zinc titanate modifier value: 20%, pH 7, and scan speed: 300 mv/s. Also, after drawing the cyclic voltametric calibration curve of the 4-chlorophenol pollutant, the target sensor showed a linear behavior with a correlation coefficient of 0.9912. The response range of the sensor was 1.3–1000 μM and the limit of detection (LOD) was 0.93 μM. For the reproducibility of the measurements, the percentage of relative standard deviation (%RSD) was determined, which was measured to be 27.9% at a concentration of 0.75 μM. The increase in the intensity of the 4-chlorophenol oxidation current and the displacement of its oxidation potential in the obtained results indicated the electrocatalytic properties of p-copper oxide/n-zinc titanate semiconductor. Finally, the antimicrobial property of p-CuO/n-ZnTiO3 semiconductor was investigated at concentrations of 0.15–70 mg/ml on E. coli and S. aureus bacteria. Based on the obtained results, the effective concentration of the desired p-copper oxide/n-zinc titanate semiconductor in inhibiting E. coli and S. aureus bacteria was determined at about 1.09 and 2.18 mg/ml, respectively. Eventually, the p-CuO/n-ZnTiO3 multifunctional heterojunction semiconductor showed structural stability and reusability even after 5 cycles of continuous use. Also, the p-CuO/n-ZnTiO3 multifunctional heterojunction semiconductor showed suitable performance and higher efficiency than other similar semiconductors synthesized in recent years.Article Highlights: The p-CuO/n-ZnTiO3 semiconductor was studied as a new multifunctional catalyst. The p-CuO/n-ZnTiO3 showed suitable photocatalytic properties under visible light. The p-CuO/n-ZnTiO3 showed good electrocatalytic oxidation for 4-chlorophenol. The p-CuO/n-ZnTiO3 showed high antimicrobial properties for the types of bacteria. [ABSTRACT FROM AUTHOR]

It is of great importance to design and develop electrocatalysts that are both long-lasting and efficient for seawater oxidation. Herein, a three-dimensional porous cauliflower-like Ni3S2 foam on Ni foam (Ni3S2 foam/NF) is proposed as a high-performance electrocatalyst for the oxygen evolution reaction in alkaline seawater. The as-synthesis Ni3S2 foam/NF achieves exceptional efficacy, achieving a current density of 100 mA·cm−2 at mere overpotential of 369 mV. Notably, its electrocatalytic stability extends up to 1000 h at 500 mA·cm−2. [ABSTRACT FROM AUTHOR]

Given the inherent potential of seawater, industrial wastewater, and residential water as inherent feedstocks for hydrogen production through water electrolysis, there is a critical demand for the exploration of robust and stable hydrogen-evolving catalysts that can operate effectively across a diverse range of pH conditions. However, the pursuit of hydrogen-evolving electrocatalysts that demonstrate both good stability and high efficiency over a wide pH range remains a formidable challenge. Here we report the rational design and synthesis of an outstanding nanoporous hybrid electrocatalyst consisting of intermetallic cobalt-molybdenum alloy particles anchoring on MoO2 cuboid arrays, which demands very low overpotentials of 72, 123 and 134 mV to deliver a current density of −100 mA·cm−2 for hydrogen evolution reaction under alkaline, neutral and acidic conditions, respectively. These catalytic activities are superior to most non-precious-metal-based catalysts documented in the literatures, and are even comparable to noble metal catalysts. In particular, this alloy electrocatalyst exhibits excellent stability at 50 or 300 mA·cm−2 without obvious activity degradation, which is further supported by the undetectable changes in the surface chemical valence states on the basis of in-situ X-ray photoelectron spectroscopic studies. This study provides an innovative strategy for the design and synthesis of effective non-noble intermetallic catalysts for pH-universal hydrogen evolution over a wide pH range. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) is a viable alternative to the finite fossil fuels to meet the escalating energy demands. Water splitting is a cleaner way of producing H2, which can effectively generate electricity via fuel cells. The slower oxygen evolution reaction (OER) with large overpotential hinders the practicality of the electrocatalytic water-splitting process to generate H2. Cobalt titanate (CoTiO3) and graphitic carbon nitride (g-C3N4) are promising candidates for OER catalysts. The composite of CoTiO3 supported on phosphorous doped g-C3N4 substrate (CoTiO3/P-C3N4) has been synthesized and demonstrated as an excellent electrocatalyst with enhanced charge transport properties exhibiting a lower overpotential of 310.0 mV, a lower charge transfer resistance (Rct) and faster OER kinetics. The synergistic interaction of CoTiO3 and P-C3N4 at the hetero-interface has resulted in enhancing the conductivity and the accessible active sites. The composite also exhibited appreciable operational stability and Faradaic efficiency. CoTiO3/P-C3N4 was thus proved to be competent to substitute the unstable and expensive benchmark catalysts in terms of cost, activity, and stability. [ABSTRACT FROM AUTHOR]

The corrosion method offers a viable means to fabricate efficient electrocatalysts for electrochemical reactions, ensuring strong adhesion between the substrate and the formed material and minimizing resistance between the catalyst and the electrode. This study introduces a method for synthesizing a high-performance oxygen evolution reaction (OER) catalyst by cultivating a transition metal-based multimetallic hydroxide on Ni foam via corrosion. The hydroxide, comprising Ni, Fe, Co, Mn, and Cr, uniformly coated the Ni foam, ensuring even distribution of each transition metal within the catalyst. The resultant NiFeCoMnCr hydroxide catalyst demonstrated enhanced OER performance, evidenced by reduced overpotential and improved stability, outperforming binary, ternary, and quaternary hydroxides. [ABSTRACT FROM AUTHOR]

Hydrogen evolution reaction (HER) stands out among conventional hydrogen production processes by featuring excellent advantages. However, the uncompetitive production cost due to the low energy efficiency has hindered its development, necessitating the introduction of cost-effective electrocatalysts. In this study, we introduced samarium doping as a high-potential approach to improve the electrocatalytic properties of nickel phosphide (Ni2P) for efficient HER. Samarium-doped Ni2P was synthesized via a facile two-step vapor–solid reaction technique. Different physical and electrochemical analyses showed that samarium doping significantly improved pure Ni2P characteristics, such as particle size, specific surface area, electrochemical hydrogen adsorption, intrinsic activity, electrochemical active surface area, and charge transfer ability in favor of HER. Namely, Ni2P doped with 3%mol of samarium (Sm0.03Ni2P) with a Tafel slope of 67.8 mV/dec. and overpotential of 130.6 mV at a current density of 10 mA/cm2 in 1.0 M KOH solution exhibited a notable performance, suggesting Sm0.03Ni2P and samarium doping as a remarkable electrocatalyst and promising promoter for efficient HER process, respectively. [ABSTRACT FROM AUTHOR]

Large surface area of electrocatalyst plays significant role in achieving high performance of water splitting. In this work, palladium–ruthenium (PdRu) binary alloys have been prepared via liquid phase deposition technique at low temperature. PdRu alloy with two dimensional nanosheets has been prepared at the growth temperature of 42 °C. The alloy is crystalline with the existence of minor phase of PdRu. The EDS mapping verifies the presence of Pd and Ru element in the alloy. The X-ray photoelectron spectroscopy (XPS) confirms the formation of PdRu. The sample tested in acidic solution yielded the highest current density and the lowest tafel slope value due to the lowest of charge transfer resistance with the value of 6 Ω. According to LSV measurement, the highest current density of 11.76 mA was yielded at the applied potential of 161 mV. The reduction current increases with the scanning rate with the highest reduction current of 1.8 mA cm−2 was obtained at the scanning rate of 10 mV/s. The electrocatalytic results of this work signify that PdRu nanosheets have potential to be utilized as efficient electrocatalyst for water splitting. [ABSTRACT FROM AUTHOR]

In order to advance sustainable energy technologies like fuel cells and metal-air batteries, it is crucial to use an electrocatalyst that is very efficient for the process of oxygen evolution. The production of Co3O4 nanostructures led to the creation of a multiporous nanostructure. The research used an approach that utilised a simple, cost-effective, and low-temperature synthesis procedure. The catalytic activity of Co3O4 nanostructures, which have a high degree of porosity and include mesoporous nanostructures, was shown to be substantial. The catalyst has the ability to enhance the highly reactive oxygen reactions at the anode, hence increasing the combined effect of charge transfer at the interface and the porous structure of Co3O4 nanostructures. The results of this study demonstrate that Co3O4 nanostructures exhibit a significant overpotential value of 321 mV at 10 mA/cm2, a Tafel slope of 72 mV Dec−1, and excellent stability when used as electrocatalysts for the oxygen evolution process (OER) in real-world situations. [ABSTRACT FROM AUTHOR]

To improve the performance of the system, it is of great importance to develop efficient catalysts for ethanol (EtOH) electro-oxidation. Pd/B electrocatalyst was synthesized using a sonochemical method. Structural and electrochemical properties of the prepared nanomaterial were investigated using electrochemical and physical techniques such as Raman spectroscopy, electrochemical impedance spectroscopy (EIS), x-ray diffraction (XRD), zetersizer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and energy-dispersive x-ray spectroscopy (EDS) and cyclic voltammetry (CV). FTIR confirmed all the functional groups of carbon black, Pd/C, borophene, and Pd/B, and the crystallinity was investigated using XRD. EIS showed that Pd/B has a faster charge transfer and, through investigation using CV, Pd/B showed a more negative onset potential and higher current (−0.76 V vs. Ag|AgCl; 0.07 mA) than Pd/C (−0.65 V vs. Ag|AgCl; 0.05 mA), indicating a more catalytic behavior and tolerance of Pd/B. The active sites could be attributed to the addition of borophene. During the anodic sweeping direction of Pd/B electrocatalyst, it was observed that the ratio of backward peak current (Ibwd) to forward peak current (Ifwd), (Ibwd/Ifwd) of in a 2 M of NaOH + 2 M of EtOH is almost equal to (Ibwd/Ifwd) 1 which shows excellent tolerance of Pd/B to poisoning by ethanol intermediate species. The electron transfer rate (Ks) values for Pd/B at 0.1 M, 0.5 M, 1 M, 1.5 M, and 2 M were estimated to be 4.50 × 10−13 s−1, 1.08 × 10−12 s−1, 4.28 × 10−13 s−1, 5.25 × 10−14 s−1 and 9.35 × 10-14 s−1. At 2 M there is a faster electron transfer than at other concentrations which is also evidenced by the obtained diffusion values (D) of the system which were found to be 2.92 × 10−7 cm2 s−1, 4.72 × 10−8 cm2 s−1, 4.82 × 10−8 cm2 s−1, 1.22 × 10−7 cm2 s−1, and 9.12 × 10−8 cm2 s−1. The electrochemically active surface area (ECSA) is strongly related to intrinsic activity, Pd/B (1.85 cm2/mg × 10−5 cm2/mg) denotes the highest Pd-O stripping charge than Pd/C (1.13 cm2/mg × 10−5 cm2/mg). [ABSTRACT FROM AUTHOR]

Recent development and expansion in electrochemical water splitting processes have driven the research community to explore an efficient, economical and eco-friendly electrocatalyst. Within this domain, the electrocatalytic oxygen evolution reaction (OER) presents a notable challenge due to its inherent inefficiency arising from a sluggish four-electron transfer process. In the present study, we investigated a hydrothermal technique for synthesizing an electrocatalyst featuring MnO-embedded CoFe2O4 spinel oxide, which is firmly anchored onto a nickel foam (NF) substrate. The electrocatalyst demonstrated impressive performance, exhibiting exceptional stability over an 82-h endurance test. A significantly smaller overpotential was required for OER, achieving a notable decrease of 179 mV. Furthermore, it displayed a Tafel value of approximately 68 mV dec−1 at current density of 10 mA cm−2 for OER, underscoring its exceptional electrocatalytic performance. In light of these compelling findings, the current research has introduced a feasible, environmentally friendly, and potentially high-impact strategy towards the development of cost-effective transition metal-based catalysts, highly suitable for use as electrodes in electrochemical water splitting applications. [ABSTRACT FROM AUTHOR]

In this work, the CeO2 nanoparticles were dispersed onto the surface of graphene oxide (GO), followed by electrodeposition of Pt–Pd alloy nanoparticles on the CeO2 surface to fabricate Pt–Pd@CeO2/graphene oxide composites (Pt–Pd@CeO2/GO). Morphological investigation was conducted using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The results of morphological characterization revealed that CeO2 nanoparticles acted as cores, while Pt–Pd alloy nanoparticles formed shells. The electrocatalytic oxidation performance of Pt–Pd@CeO2/GO composites for methanol electro-oxidation reaction (MOR) was systematically investigated. The mass activity for MOR on Pt1Pd1.3@CeO2/GO electrocatalyst was 1128 mA·mgPt+Pd−1, which was 5.0-fold higher than that of Pt/C catalysts. The synergistic effect between Pt and Pd, along with the active oxygen-containing species of CeO2 effectively enhanced catalytic activity. This work presents a novel approach to developing catalysts with high catalytic performance for MOR. [ABSTRACT FROM AUTHOR]

As one of the major greenhouse gases, CO2 is significantly influencing global climate change. Efficient utilization of CO2 is considered an important approach to address the current environmental and energy challenges. In particular, using CO2 as a raw material for the production of hydrocarbons is an attractive strategy for reducing carbon emissions while ensuring a stable energy supply. In this study, fluorine (F) doped ZnLa layered double hydroxide (F-ZL-LDH) and F-doped ZnCe layered double hydroxide (F-ZC-LDH) were prepared using a hydrothermal synthesis method. The materials' structural composition and morphology were analyzed using X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The research results demonstrate that both catalysts exhibit abundant active sites, high selectivity, and excellent electrocatalytic performance for CO2RR to generate CO, with Faradaic efficiencies reaching 89.29% and 89.87% for F-ZL-LDH and F-ZC-LDH, respectively. The doping of fluorine results in the presence of numerous defects and pore structures on the surfaces of F-ZC-LDH and F-ZL-LDH, increasing the surface active area and enhancing charge transfer rates. Meanwhile, F doping facilitates CO2 adsorption and mass transfer on the electrode surface. Moreover, F doping in the catalysts also restricts the adsorption and desorption of *H during the competing hydrogen evolution reaction (HER) process. The effective management and rapid conversion of CO2 to various organic compounds and chemical fuels to facilitate carbon cycle and reduce atmospheric CO2 concentration have become a hot topic in current technological advances worldwide. Among the various electrocatalytic CO2 reduction reaction (CO2RR) products, carbon monoxide (CO) is the product with the highest kinetic accessibility. In this paper, F-ZL-LDH and F-ZC-LDH composite materials were prepared using a hydrothermal synthesis method. Based on preliminary studies, a molar ratio of M2+:M3+ of 3:1 was determined to provide better catalytic performance,and ammonium fluoride content of 30% of the cation molar ratio of M2+ + M3+. The introduction of fluorine (F) improves the catalytic performance of both materials, with a greater enhancement observed for ZL-LDH. At − 1.3V vs. RHE potential, The research results demonstrate that both catalysts exhibit abundant active sites, high selectivity, and excellent electrocatalytic performance for CO2RR to generate CO, with Faradaic efficiencies reaching 89.29% and 89.87% for F-ZL-LDH and F-ZC-LDH, respectively. the fluorination treatment of ZC-LDH and ZL-LDH catalysts significantly enhances their electrocatalytic activity for the CO2 reduction reaction, particularly for the production of CO. These findings contribute to the development of efficient catalysts for CO2 electrochemical reduction and hold promise for advancing the field of CO2 utilization and renewable energy conversion. [ABSTRACT FROM AUTHOR]

Advancing efficient and affordable electrocatalysts to boost the oxygen evolution reaction (OER) is pivotal for sustainable green hydrogen production. Herein, we propose the fabrication of nickel-iron alloy nanoparticles-encapsulated on N-doped vertically aligned graphene array on carbon cloth (NiFe@NVG/CC) as a highly active three-dimensional (3D) catalyst electrode for OER. In 1 M KOH, such NiFe@NVG/CC demonstrates outstanding catalytic performance, necessitating merely overpotential of 245 mV for achieving a current density of 10 mA·cm−2, a remarkably low Tafel slope of 36.2 mV·dec−1. Furthermore, density functional theory calculations validate that the incorporate of N species into graphene can reinforce the electrocatalytic activity though reducing the reaction energy barrier during the conversion of ⋆O to ⋆OOH intermediates. The outstanding performance and structural benefits of NiFe@NVG/CC offer valuable insights for the development of innovative and efficient electrocatalysts for water oxidation. [ABSTRACT FROM AUTHOR]

The development of renewable energy technologies, such as fuel cells and metal-air batteries, relies heavily on the availability of highly efficient electrocatalysts for the oxygen evolution reaction (OER). In this study, a mesoporous Fe3O4-ZnO nanocomposites was synthesized using a simple and economically viable approach at a relatively low temperature. The observed catalytic activity of the prepared Fe3O4-ZnO nanocomposites mesoporous nanostructure was found to be remarkable. Additionally, the nanostructure exhibited a high tolerance to methanol and demonstrated durability towards oxygen evolution reaction (OER) in alkaline media. In the course of the experiment, it was observed that the catalyst exhibited noteworthy activity in the oxygen evolution reaction (OER) when compared to the commercially available RuO2 catalyst. This was evident through a more negative onset potential and higher current. The catalyst's notable capacity for high oxygen reaction activity may potentially enhance the synergistic effect resulting from the combination of defect sites and the porous structure of Fe3O4-ZnO nanocomposites. The findings of this study indicate that the Fe3O4-ZnO nanocomposites exhibit promising attributes as an electrocatalyst with overpotential and Tafel slope value of 350 mV and 62 mVdec−1 for the oxygen evolution reaction (OER) in real-world scenarios. [ABSTRACT FROM AUTHOR]

The development of renewable and affordable energy is crucial for building a sustainable society. In this context, establishing a sustainable infrastructure for renewable energy requires the integration of energy storage, specifically use of renewable hydrogen. The hydrogen evolution reaction (HER) of electrochemical water splitting is a promising method for producing green hydrogen. Recently, two-dimensional nanomaterials have shown great promise in promoting the HER in terms of both fundamental research and practical applications due to their high specific surface areas and tunable electronic properties. Among them, molybdenum disulfide (MoS2), a non-noble metal catalyst, has emerged as a promising alternative to replace expensive platinum-based catalysts for the HER because MoS2 has a high inherent activity, low cost, and abundant reserves. At present, greatly improved activity and stability are urgently needed for MoS2 to enable wide deployment of water electrolysis devices. In this regard, efficient strategies for precisely modifying MoS2 are of interest. Herein, the progress made with MoS2 as an HER catalyst is reviewed, with a focus on modification strategies, including phase engineering, morphology design, defect engineering, heteroatom doping, and heterostructure construction. It is believed that these strategies will be helpful in designing and developing high-performance and low-cost MoS2-based catalysts by lowering the charge transfer barrier, increasing the active site density, and optimizing the surface hydrophilicity. In addition, the challenges of MoS2 electrocatalysts and perspectives for future research and development of these catalysts are discussed. [ABSTRACT FROM AUTHOR]

The growing energy demand and environmental issues have encouraged the development of novel and sustainable energy. Hydrogen is one of the cleanest and most sustainable energy sources that provides an environmentally friendly alternative future fuel. The recent development in hydrogen production through electrocatalytic water-splitting is somewhat high-performance. The potential electrocatalysts play an essential role in hydrogen evolution reactions (HER) for electrochemical water splitting, where expensive and low-abundance platinum-based materials are the standard catalysts for HER. Herein, metal-free, low-cost, and naturally abundant chebulic myrobalan was employed as a source for the preparation of porous carbon by direct pyrolysis route, and the resulting porous carbon was utilized as an electrocatalyst for the production of hydrogen gas. The various analytical techniques confirmed the existence of sulfur, nitrogen, and oxygen in the prepared chebulic myrobalan-derived porous carbon (CM-PC). The presence of effective heteroatoms in the CM-PC may lead to interactive effects between the heteroatoms and porous carbon structures; this suggests the enhancement of the electrochemical performance of HER. The surface area of CM-PC was obtained as 675 m2 g−1 by BET measurement. The CM-PC exhibited a moderate degree of graphitization with hydrophilic functionalities. Based on these excellent properties, the CM-PC was used as an electroactive material to fabricate the working electrode and as a metal-free electrocatalyst for HER in a 0.5 M H2SO4 aqueous solution. The resulting CM-PC delivered a superior catalytic activity toward HER with a Tafel slope of ~ 79 mV decade–1 (Overpotential − 166 mVRHE at a current density of − 10 mA cm–2) and excellent long-term stability in an acidic medium. Importantly, these findings prove that the chebulic myrobalan (biomass) was turned into an effective electrocatalyst for hydrogen generation in the economical route, thereby challenging the uniqueness of platinum catalysts in the hydrogen economy. The result indicates that as-prepared catalysts (CM-PC) have excellent application value in energy and environment. [ABSTRACT FROM AUTHOR]

Controllable and scalable preparation of electrocatalyst materials holds significant importance for their practical application. Magnetron sputtering is a highly effective synthesis method, known for its producing uniform films and allowing easy control of component compositions. In this paper, we propose an in-situ synthesis method for layered double hydroxide (LDH) electrocatalysts through sacrificing magnetron sputtered films. The resulting FeCo-LDH catalyst demonstrated a low overpotential of only 300 mV at 10 mA·cm−2. Furthermore, we conducted spectroscopic analysis to investigate the surface changes of the catalysts during the oxygen evolution reaction (OER) process. Our findings indicated that the formation of Co oxyhydroxides plays a beneficial role in enhancing the catalytical performance of the FeCo-LDH for OER reaction. This restructuring strategy of converting a magnetron-sputtered sacrificial film into a catalytical LDH introduces a new avenue to the synthesis of transition metal-based electrocatalysts. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 reduction reaction (CO2RR) has received widespread attention as a promising method for producing sustainable chemicals and mitigating the global warming. Here, we demonstrate a general and facile synthetic route for the metal-nitrogen-carbon (M-N-C) type catalyst by simply calcinating metal acetate and urea with commercial carbon black, which have potential application in CO2RR. The synthesized Ni−NC−600 catalyst has the structure of single Ni atom coordinated with one N atom and three C atoms (Ni−N1C3), which is suggested by X-ray absorption spectroscopy. The Ni−NC−600 catalyst exhibits high CO2RR catalytic performance and a high CO Faraday efficiency above 98% in a wide potential range from −0.7 to −1.3 V (vs. reversible hydrogen electrode (RHE)), superior to most of the reported Ni−N−C catalysts. This work has developed a facile strategy to synthesize high performance CO2RR catalyst. [ABSTRACT FROM AUTHOR]

Constructing interfaces in heterostructures is effective for modulating the electronic properties of electrocatalysts. The hollow CoMoO4-Co3O4 heterostructure (HCMCH) was prepared as a bifunctional electrocatalyst for Li-O2 battery. The different components in CoMoO4-Co3O4 heterostructure presented the efficient coupling and enhanced the electrocatalytic activity for aprotic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), in which it improved the obviously reduced overpotential of 300 mV (compared with the pure Ketjen black (KB) electrode), enhanced reversibility of 80% capacity retention after 6 full cycles and the superior cyclability of more than 200 cycles with an optimized strategy. The battery performance of the HCMCH was not only associated with the unique hollow structure and rich active sites but also with coupling interface constructions synergetic effects attaching to the improving conductivity and optimized the discharge conversion. These results suggested that this HCMCH electrocatalyst was a promising candidate for the Li-O2 battery and it gave a novel insight for high performance electrocatalyst designing. [ABSTRACT FROM AUTHOR]

The development of non-platinum group metal (non-PGM) and efficient multifunctional electrocatalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) with high activity and stability remains a great challenge. Herein, by in-situ transforming silver manganese composite oxide heterointerface into boosted Mott-Schottky heterointerface through a facile carbon reduction strategy, a nanorod-like silver/manganese oxide with superior multifunctional catalytic activities for ORR, OER and HER and stability was obtained. The nanorod-like silver/manganese oxide with Mott-Schottky heterointerface (designated as Ag/Mn3O4) exhibits an ORR half-wave potential of 0.831 V (vs. RHE) in 0.1 M KOH, an OER overpotential of 338 mV and a HER overpotential of 177 mV at the current density of 10 mA·cm−2 in 1 M KOH, contributing to its noble-metal benchmarks comparable performance in aqueous aluminum-air (Al-air) battery and laboratorial overall water splitting electrolytic cell. Moreover, in-situ electrochemical Raman and synchrotron radiation spectroscopic measurements were conducted to further illustrate the catalytic mechanism of Ag/Mn3O4 Mott-Schottky heterointerface towards various electrocatalytic reactions. At the heterointerface, the Ag phase serves as the electron donor and the active phase for ORR and HER, while the Mn3O4 phase serves as the electron acceptor and the active phase for OER, respectively. This work deepens the understanding of the Mott-Schottky effect on electrocatalysis and fills in the gap in fundamental physical principles that are behind measured electrocatalytic activity, which offers substantial implications for the rational design of cost-effective multifunctional electrocatalysts with Mott-Schottky effect. [ABSTRACT FROM AUTHOR]

The determination of complex structure helps to explore its reaction mechanism and provides design strategies for guiding synthesis of high-performance hydrogen evolution reaction (HER) electrocatalysts. A new mononuclear Ni(II) complex, [Ni(p-MOPhH2IDC)2(H2O)2], was synthesized by the reaction of p-MOPhH3IDC (2-(4-methoxyphenyl)-1 H-imidazole-4,5-dicarboxylic acid) and Ni(NO3)2·6H2O under solvothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR and UV-vis spectroscopy. The structure analysis revealed that the nickel center was six-coordinated octahedron coordination geometry. The electrochemical properties of the Ni(II) complex-doped carbon paste electrode (Ni-CPE) were investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in 0.5 M H2SO4 electrolyte. The HER measurements show that the η10298K (overpotential, 10 mA cm–2) of the Ni-CPE was positively shifted by 265 mv compared with the bare-CPE (without complex). The Tafel slope of the Ni-CPE was 187 mV dec− 1. These indicated that the Ni-CPE was effective for HER electrocatalytic reaction. In addition, the electrochemical sensing performances of the Ni-CPE towards H2O2 were found to have a linear response from 0.5 µM to 4.0 mM with a detection limit of 0.036 µM. The above studies prove that the Ni(II) complex can be used as an effective bi-functional molecular electrocatalyst for HER and H2O2 sensing, and provide a new approach for designing efficient, non-precious metal electrochemical catalysts. A new mononuclear Ni(II) complex, [Ni(p-MOPhH2IDC)2(H2O)2], was synthesized under solvothermal conditions. The electrochemical properties of the Ni(II) complex-doped carbon paste electrode (Ni-CPE) were investigated. In the HER study, the Ni-CPE has more positive overpotentials (η10293K), smaller Tafel slopes and lower activation energies in the HER process compared to the bare-CPE, demonstrating that the Ni-CPE has effective electrocatalytic hydrogen evolution activity. Moreover, electrochemical sensing performance shows that Ni-CPE has good detection ability for H2O2 and exhibit good stability and anti-interference properties. Therefore, the Ni-CPE can be used as an effective bifunctional electrocatalyst. [ABSTRACT FROM AUTHOR]

Hydrogen is a clean fuel with high energy density, considered one of the alternative energy sources of the future. Hydrogen evolution reaction (HER) could produce pure hydrogen on a large scale while striving for effective electrocatalysts. Here, binary and ternary mixed transition metals (Mn, Co, and Ni) were synthesized by an electrodeposition method and employed as efficient HER electrocatalysts. It was found that the combination of transition metals could positively tune the corresponding morphology and activity rather than using single metals. Namely, NiMn electrocatalysts with an onset potential of 83 mV and a Tafel slope of 103 showed superior activity toward HER in alkaline media compared to the other developed electrocatalysts. This high activity was related to improved intrinsic activity, higher energy efficiency, and enhanced conductivity thanks to the synergy between manganese and nickel. NiMn electrocatalyst also displayed a durable and stable performance, rendering it a promising electrocatalyst for efficient electrocatalysis of HER. [ABSTRACT FROM AUTHOR]

The research aims to investigate the potential of using Ag/PMAc-g-CNT as a high-efficient catalyst for overall water splitting and supercapacitor applications. The results of Tafel slope measurements for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) showed that the Ag/PMAc-g-CNT catalyst had a lower Tafel slope of 22.62 mV dec−1 and 62.74 mV dec−1, respectively, compared to the other electrocatalysts. Additionally, the capacitance value of the Ag/PMAc-g-CNT catalyst was found to be 41.87 F at 0.5 A/g current density which is much higher than that of the Ag/PMAc catalyst. These results demonstrate that the Ag/PMAc-g-CNT catalyst has superior properties in terms of electrochemical activity, stability and energy storage capacity, making it a promising material for both water splitting and supercapacitor applications. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting stands as a promising method for harnessing energy from renewable sources. However, substantial overpotential required for sluggish oxygen evolution reaction (OER) hampers its widespread adoption. In this study, a CuSe@PPy hybrid is being created by hydrothermally layering polypyrrole on top of CuSe. This hybrid electrocatalyst outperforms both pure CuSe and PPy in terms of OER efficiency. Structural and morphological analyses, including powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller (BET), confirm that the synthesized CuSe@PPy composite exhibits high crystallinity, nanostructured granular morphology, and a hexagonal structure with a large surface area. Evaluation of its electrocatalytic performance for water oxidation in a 1 M KOH alkaline medium reveals CuSe@PPy hybrid's exceptional durability, achieving 35 mA cm−2 for 100 h. This durability is attributed to PPy coating on its surface, which facilitates efficient electron conduction. Coupling of PPy with CuSe leads to reduced overpotential (248 mV), a lower Tafel slope (30 mV/dec), and decreased charge transfer resistance (2.16 Ω), enhancing OER efficiency. By modifying surface of CuSe with a conducting polymer like PPy, this study underscores potential for improving performance in various applications, including photoelectron-catalytic research and stabilizing material activity. [ABSTRACT FROM AUTHOR]

The type of catalyst support affects platinum activity and durability in direct methanol fuel cells (DMFCs). In this study, Sb with 0, 4, 8 and 12% doped SnO2 on carbon cloth (CC) support at ultra-low platinum loading (0.04 mg cm−2) is prepared. The results show that the modification of support and the use of Sb-doped SnO2 improve the electrochemical activity of the prepared electrodes. Scanning electron microscopy (SEM) indicates that the doping of SnO2 with Sb decreases the average particle size of Pt. The X-ray diffraction (XRD) patterns show that incorporating Sb and Pt nanoparticles into SnO2 would not damage the tetragonal rutile structure. The highest electrochemical surface area (ECSA) of electrodes in the acidic environment is obtained in Sb of 4%. The highest current density of 15.5 mA cm−2 is obtained at the peak potential of 0.71 V for Pt@Sb4-SnO2-CC electrode in the methanol oxidation reaction while its value is 1.2 times higher than Pt@CC. The chronoamperometry analysis and CO stripping voltammetry show that this electrode has the highest tolerance to CO. The electrochemical impedance spectroscopy demonstrates that the minimum charge transfer resistance of 17.6 (Ω cm2) is acquired for the Pt@Sb4-SnO2-CC electrode. In the active DMFC test, the high power and current density of this electrode are 11 mW cm−2 and 66 mA cm−2, respectively, at the cell voltage of 0.2 V. [ABSTRACT FROM AUTHOR]

Nitrogen-containing disinfection by-products (N-DBPs) produced in the process of drinking water disinfection are widely concerning due to the high cytotoxicity and genotoxicity. It is due to the difficulty of natural degradation of N-DBPs in water and the fact that conventional treatment systems do not effectively treat N-DBPs in drinking water. In this study, N-nitrosopyrrolidine (NPYR) in water was electrocatalytically degraded by a three-dimensional electrode reactor (3DER). This system applied graphite plates as anode and cathode. The granular activated carbon (GAC) was used as third electrode. The degradation of NPYR using a continuous flow three-dimensional electrode reactor was investigated by examining the effects of flow rate, current density, electrolyte concentration, and pollutant concentration on the degradation efficiency, energy consumption, and reaction kinetics of GAC particle electrodes. The results showed that the optimal operating conditions were flow rate = 0.45 mL/min, current density = 6 mA/cm2, Na2SO4 concentration = 0.28 mol/L, and NPYR concentration = 20 mg/L. Under optimal conditions, the degradation of NPYR exceeded 58.84%. The main contributor of indirect oxidation was deduced from free radical quenching experiments. NPYR concentration was measured by GC–MS with DB-5 capillary column, operating in full scan monitoring mode for appropriate quantification of NPYR and intermediates. Based on the identification of reaction intermediates, a possible pathway for the electrochemical oxidation of NPYR on GAC particle electrodes was proposed. [ABSTRACT FROM AUTHOR]