Review—Recent Developments in the Applications of 2D Transition Metal Dichalcogenides as Electrocatalysts in the Generation of Hydrogen for Renewable Energy Conversion

There has never been a more pressing need to develop sustainable energy systems as dramatic climate changes emerge across the World. Some of these effects can be alleviated by the development of efficient devices that are capable of producing hydrogen gas in an environmentally acceptable manner, which in turn can be employed as a clean fuel. In this context, the splitting of water is especially attractive. However, this technology requires the design of new cost-effective electrocatalytic materials. In this review, the progress made in the development of transition metal dichalcogenides (TMDs) and their composites as electrocatalysts for both acidic and alkaline electrolysis cells and as photocatalysts for the formation of hydrogen is described and discussed. Following a short introduction to the mechanisms of the electrochemical hydrogen and oxygen evolution reactions and the photoelec- trochemical generation of hydrogen, an introduction to TMDs, their relevant general properties and the methods used in their synthesis are described. Then, the performance of various TMD-based materials in the electrochemical splitting of water is discussed, with a final brief overview of the application of TMDs in photoelectrochemical devices. Although challenges clearly remain, TMD-based materials are emerging as promising electrocatalysts and photoelectrocatalysts for the production of hydrogen. © 2022 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cite

Insight into the synergistic effect of 2D/2D layered metal selenides wrapped nickel boride nanoparticles based ternary heterostructure for constructing asymmetric supercapacitors with excellent energy density

Tuning the structural and electronic properties of layered metal selenides is a highly feasible approach for developing high-performance asymmetric supercapacitors (ASCs). In this work, a ternary heterostructure of yttrium diselenide/molybdenum diselenide (YSe2/MoSe2) with amorphous nickel boride nanoparticles (NixB NPs) was prepared by a simple hydrothermal method followed by a liquid phase route. Interestingly, this ternary heterostructure consists of multiple layers of YSe2/MoSe2 nanosheets uniformly wrapped by NixB NPs over the entire surface. The characterization results by X-ray diffraction, Raman, and X-ray photoelectron spectroscopy showed that the strong synergism between YSe2/MoSe2 and NixB NPs indicates an obvious electron transfer from NixB to the YSe2/MoSe2 hybrid, which contributes to the enhancement of the electrical conductivity of the electrode. Due to its exclusive heterostructure network, the single YSe2/MoSe2/NixB electrode achieved a specific capacitance of 893.3 F/g at 1 A/g and a capacity retention of 128.17% over 5000 cycles. In addition, the asymmetric YSe2/MoSe2/NixB||rGO device with a working potential of 1.6 V showed an impressive energy density of 39.5 Wh kg− 1 with a power density of 800 W kg− 1 and excellent cycling stability with 85.60% capacity retention after 5000 cycles in aqueous electrolyte. This result of the designed ASC device encourages the development of a new platform for the design of electrode materials based on metal selenides and metal boride

Flower-like strontium molybdate anchored on 3D N-rich reduced graphene oxide aerogel composite: An efficient catalyst for the detection of lethal pollutant nitrobenzene in water samples

Nitrobenzene (NB) is a carcinogenic water pollutant that can have dangerous effects on humans, animals, and the environment even in trace amounts. It can persist in contaminated sites and leach into the adjacent aquatic environment. Therefore, the detection of trace amounts of NB is of great interest. To address this challenge, we have fabricated strontium molybdate microflowers (SrMoO4, SMO MFs) grown on nitrogen-rich, porous three-dimensional (3D) reduced graphene oxide aerogels (SMO/N-rGO) for sensitive detection of NB in water samples. The 3D N-rGO and SMO/N-rGO composites were prepared by simple hydrothermal and precipitation methods. The fabricated SMO/N-rGO composites exhibited a porous and 3D structure with a strong synergistic effect between the SMO MFs and the N-rich porous rGO sheets with open voids that facilitate the diffusion of NB. The electrochemical detection of NB at the SMO/N-rGO modified electrode was significantly enhanced. Using amperometry (i-t), the modified SMO/N-rGO sensor was shown to have two linear response ranges in the sensing of NB, with the lower linear concentration range from 7.1 nM to 1.0 mM and the higher linear concentration range varying from 1.1 mM to 2.5 mM. In addition, the limit of detection (LOD) was calculated to be 2.1 nM using the amperometric (i-t) technique. Common nitro derivatives, biomolecules, and cations often found in water systems had no influence on the detection of NB. At the same time, a good recovery of 96.1–99.6% was obtained for real-time monitoring analysis in tap and lake water samples. In this work, new electrochemical sensors for monitoring various pollutants are developed based on anchoring conductive metal oxide electrocatalysts on porous 3D carbon aerogels

Mesoporous carbon-based materials and their applications as non-precious metal electrocatalysts in the oxygen reduction reaction

Carbon is truly astonishing and the only element that can form so many different compounds and materials. In recent years, numerous nanostructured carbon-based materials have emerged and within this family, meso- porous and ordered mesoporous carbon have attracted considerable attention. In this paper, we review the recent developments in the applications of mesoporous carbon as an electrocatalyst for the oxygen reduction reaction (ORR). The ORR is one of the most studied electrochemical reactions with applications in the energy and environmental sectors. Following a short introduction to the methodologies employed in the fabrication of mesoporous and ordered mesoporous carbon, the performance of these materials in the ORR is reviewed. Initially, metal free heteroatom doped mesoporous carbon electrocatalysts are described, highlighting the roles of N, S and B as dopants. Next, mesoporous carbon materials with Fe, Co, Mn and Ni, as isolated single atom catalysts, are introduced. The role of mesoporous carbon as a support for nanostructured electrocatalysts is then discussed. Finally, the selectivity of the mesoporous carbon-based electrocatalysts for the four and two-electron ORR is discussed. While further developments and advancements are needed, it is clear that these mesoporous carbon-based materials have the potential to give highly efficient electrocatalysts for both the four and two electron ORR. Indeed, many of the reported electrocatalysts can outperform the commercial Pt/carbon electrocatalysts in alkaline solutions

Facile synthesis of cellulose microfibers supported palladium nanospindles on graphene oxide for selective detection of dopamine in pharmaceutical and biological samples

The cost-effective synthesis of novel functional nanomaterials has received significant attention in the physical and chemical sciences due to their improved surface area, high catalytic activity along with unique morphological features. This paper reports a facile and eco-friendly synthesis of spindle-like palladium nanostructures (PdSPs) on graphene oxide-cellulose microfiber (GO-CMF) composite for the first time. The GO-CMF/PdSPs composite was synthesized by an electrochemical method without the use of additional surfactants and capping agents. The synthesized materials were characterized and confirmed by using transmission electron microscopy, high-resolution scanning electron microscopy, X-ray diffraction spectroscopy, Raman spectroscopy and Fourier-transform infrared spectroscopy. As-synthesized GO-CMF/PdSPs composite modified electrode was used as a selective electrocatalyst for the oxidation of dopamine (DA). The electrochemical redox behaviors of DA were investigated using cyclic voltammetry (CV). The CV results revealed that the GO-CMF/PdSPs composite modified electrode has 10 folds enhanced oxidation current response to DA than GO, PdSPs and GO-CMF modified GCEs. Under optimized conditions, the GO-CMF/PdSPs composite sensor exhibits a linear response to DA in the concentration range from 0.3 to 196.3 μM with the lower detection limit of 23 nM. The nanocomposite electrode also shows promising features towards the reliable and selective detection of DA, which includes high stability, reproducibility and high selectivity towards the commonly interfering species such as ascorbic acid, uric acid, and dihydroxybenzene isomers. The sensor was successfully tested for the real-time detection of DA in the commercial DA injections and human serum samples

Review—Recent Developments in the Applications of 2D Transition Metal Dichalcogenides as Electrocatalysts in the Generation of Hydrogen for Renewable Energy Conversion

There has never been a more pressing need to develop sustainable energy systems as dramatic climate changes emerge across the World. Some of these effects can be alleviated by the development of efficient devices that are capable of producing hydrogen gas in an environmentally acceptable manner, which in turn can be employed as a clean fuel. In this context, the splitting of water is especially attractive. However, this technology requires the design of new cost-effective electrocatalytic materials. In this review, the progress made in the development of transition metal dichalcogenides (TMDs) and their composites as electrocatalysts for both acidic and alkaline electrolysis cells and as photocatalysts for the formation of hydrogen is described and discussed. Following a short introduction to the mechanisms of the electrochemical hydrogen and oxygen evolution reactions and the photoelec- trochemical generation of hydrogen, an introduction to TMDs, their relevant general properties and the methods used in their synthesis are described. Then, the performance of various TMD-based materials in the electrochemical splitting of water is discussed, with a final brief overview of the application of TMDs in photoelectrochemical devices. Although challenges clearly remain, TMD-based materials are emerging as promising electrocatalysts and photoelectrocatalysts for the production of hydrogen. © 2022 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/ by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cite

Electrocatalytic Studies of Coral-Shaped Samarium Stannate Nanoparticles for Selective Detection of Azathioprine in Biological Samples

An electrochemical sensor was developed based on the pyrochlore-type binary metal oxide samarium stannate nanoparticles (Sm2Sn2O7 NPs). The Sm2Sn2O7 NPs were prepared using the co-precipitation technique, and they were subjected to physiochemical characterizations such as X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The morphological and elemental information was interpreted by field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) analysis. The electrocatalytic sensing of the pharmaceutical drug azathioprine (AZN) was exhibited using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over the Sm2Sn2O7/GCE (GCE - glassy carbon electrode). The Sm2Sn2O7/GCE had high electrocatalytic behavior for AZN determination with a limit of detection of 4 nM and superior sensitivity of 0.27 μA μM–1 cm–2, and it has a linear range from 0.01 to 948 μM. Furthermore, the Sm2Sn2O7/GCE exhibited excellent selectivity, long-term storage stability, good repeatability, and reproducibility for AZN detection. Additionally, the Sm2Sn2O7/GCE sensor possessed considerable importance for the sensing of AZN in biological fluids for practical applications. We believe that this pyrochlore-based Sm2Sn2O7 NP electrocatalyst can act as a prospective electrode material for the electrochemical determination of AZN in clinical biological applications

Synthesis and Characterization of Pyrochlore-Type Praseodymium Stannate Nanoparticles: An Effective Electrocatalyst for Detection of Nitrofurazone Drug in Biological Samples

Apart from perovskites, the development of different types of pyrochlore oxides is highly focused on various electrochemical applications in recent times. Based on this, we have synthesized pyrochlore-type praseodymium stannate nanoparticles (Pr2Sn2O7 NPs) by using a coprecipitation method and further investigated by different analytical and spectroscopic techniques such as X-ray diffraction, Raman spectroscopy, field emission-scanning electron microscopy, high resolution-transmission electron microscopy, and X-ray photoelectron spectroscopy analysis. Followed by this, we have designed a unique and novel electrochemical sensor for nitrofurazone detection, by modifying the glassy carbon electrode (GCE) with the prepared Pr2Sn2O7 NPs. For that, the electrochemical experiments were performed by using cyclic voltammetry and differential pulse voltammetry techniques. The Pr2Sn2O7 NPs modified GCE exhibits high sensitivity (2.11 μA μM−1 cm−2 ), selectivity, dynamic linear ranges (0.01−24 μM and 32−332 μM), and lower detection limit (4 nM). Furthermore, the Pr2Sn2O7 NPs demonstrated promising real sample analysis with good recovery results in biological samples (human urine and blood serum) which showed better results than the noble metal catalysts. Based on these results, the present work gives clear evidence that the pyrochlore oxides are highly suitable electrode materials for performing outstanding catalytic activity toward electrochemical sensors

Mesoporous carbon-based materials and their applications as non-precious metal electrocatalysts in the oxygen reduction reaction

Carbon is truly astonishing and the only element that can form so many different compounds and materials. In recent years, numerous nanostructured carbon-based materials have emerged and within this family, meso- porous and ordered mesoporous carbon have attracted considerable attention. In this paper, we review the recent developments in the applications of mesoporous carbon as an electrocatalyst for the oxygen reduction reaction (ORR). The ORR is one of the most studied electrochemical reactions with applications in the energy and environmental sectors. Following a short introduction to the methodologies employed in the fabrication of mesoporous and ordered mesoporous carbon, the performance of these materials in the ORR is reviewed. Initially, metal free heteroatom doped mesoporous carbon electrocatalysts are described, highlighting the roles of N, S and B as dopants. Next, mesoporous carbon materials with Fe, Co, Mn and Ni, as isolated single atom catalysts, are introduced. The role of mesoporous carbon as a support for nanostructured electrocatalysts is then discussed. Finally, the selectivity of the mesoporous carbon-based electrocatalysts for the four and two-electron ORR is discussed. While further developments and advancements are needed, it is clear that these mesoporous carbon-based materials have the potential to give highly efficient electrocatalysts for both the four and two electron ORR. Indeed, many of the reported electrocatalysts can outperform the commercial Pt/carbon electrocatalysts in alkaline solutions

Investigation of the electrocatalytic activity of bismuth-substituted pyrochlore Y2Sn2O7 for the voltammetry determination of the antipsychotic drug

Pyrochlore oxides are considered active candidates for various electrochemical applications due to their cationic charges and anionic deficiency. At the same time, the cationic substitution of pyrochlore is a crucial parameter to improve the catalytic activity of electrode materials. Against this background, this article aims to synthesize bismuth-substituted defective pyrochlore-yttrium tin oxide nanoparticles (Bi0.6Y1.4Sn2O7; BYSO NPs) and construct an electrochemical sensor for the antipsychotic chlorpromazine (CHPMZ). The catalyst was prepared by co-precipitation technique followed by thermal treatment. The analytical methods, such as p-XRD, FT-IR, TGA, and XPS, confirmed the successful substitution of Y3+ by Bi3+. The morphology of the as-prepared catalysts was analyzed by the FE-SEM and TEM techniques, which shows that the size of nanoparticles is ⁓20–30 nm. From the CV results, the cationic substitution enhances the electrocatalytic oxidation of CHPMZ due to the intrinsic activity enhancement by the substitution with a large size cation and the anionic deficiency of the pyrochlore structure. Moreover, the heterogeneous rate constant of CHPMZ on BYSO/SPCE was calculated to be 4.49 × 10−3 cm/s, indicating that the oxidation of CHPMZ on BYSO/SPCE is quasi-reversible. The electrode modified with BYSO NPs showed wider linear ranges (0.01–58.41 μM, 78.41–1158 μM), high sensitivity (1.03 μA/μM/cm2) with a low detection limit of 3 nM. The modified electrodes showed good selectivity, repeatability, and excellent stability for the detection of CHPMZ. Moreover, the constructed sensor showed promising results in practical analysis with good recovery in human blood serum and urine samples