Materials For Hydrogen Evolution Reaction Research Articles

Trimetallic CuO/Ag/NiO supported with silica nanoparticles based composite materials for green hydrogen production

Production and utilization of grey and blue hydrogen is responsible for emission of millions of tons of carbon dioxide (CO2) across the globe. This increased emission of CO2 has severe repercussions on the planet earth and in particular on climate change. Here in, we explored advance bimetallic (BM) CuO/Ag and trimetallic (TM) CuO/Ag/NiO based nanoporous materials supported with silica nanoparticles (SiNPs) via sol–gel route. The explored nanocatalysts were characterized by Powder X-ray diffraction (P-XRD), scanning electron microscopy (SEM), transmittance electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and Raman spectroscopic techniques. These advance nanocatalysts were evaluated for the green hydrogen production through electrocatalysis and photocatalysis. The catalysts exhibited an exceptional catalytic performance, the onset potential for hydrogen evolution reaction (HER) was determined to be − 0.9 V BMSiNPs-GCE and − 0.7 V (vs Ag/AgCl) for TMSiNPs-GCE, whereas η@10 for BMSiNPs-GCE and TMSiNPs-GCE is − 1.26 and − 1.00 V respectively. Significantly, the TMSiNPs composite and the BMSiNPs composite exhibited superior photochemical H2 evolution rates of 1970.72 mmol h−1 g−1 and 1513.97 mmol h−1 g−1, respectively. The TMSiNPs catalyst presents a highly promising material for HER. This study reveals a cost-effective approach to develop sustainable and resourceful electrocatalysts for HER.

Corrosion behavior of electrodeposited nickel-based coatings with W, Mo, and TiOx

The corrosion behavior of electrodeposited nickel-based coatings with W, Mo, and TiOx as potential catalytic material for hydrogen evolution reaction (HER) in highly aggressive media, 0.5 M H2SO4 and 6 M KOH, is presented. A wide range of electrochemical and spectroscopic methods have been used, such as linear sweep voltammetry, open-circuit potential (OCP), electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) to characterize the coatings before and after a residence time of 336 h in the model corrosion environment. The NiW alloy and the NiWTiOx composite coating demonstrate the best corrosion resistance in an acidic environment due to the stable tungstate phase formation (H0.33O3W and H2O4W) on the surface. In alkaline environments, all the systems studied show enviable resistance, but the alloys containing molybdenum stand out.

ELECTROLYTIC CATALYSTS BASED ON TUNGSTEN AND CARBON COMPOUNDS FOR THE HYDROGEN EVOLUTION REACTION

The hydrogen evolution reaction (HER) is one of the most promising methods of obtaining high-purity hydrogen. However, the high cost and limited resources of materials with low cathodic hydrogen evolution overvoltage values, such as platinum group metals, are the main obstacles to the use HER for obtaining hydrogen on an industrial scale. Therefore, it is necessary to develop new alternative materials and methods of their production. One of the promising materials are catalysts based on refractory metals, in particular tungsten carbides. Metal tungsten can also be used for these purposes. In our opinion, high-temperature electrochemical synthesis (HTES) in molten salts can be a promising method of obtaining materials with properties that meet the requirements for effective catalysts, namely: ultra-dispersity, high specific surface area, mesoporosity and defective structure, high chemical and electrochemical stability. Therefore, the purpose of this work is to evaluate the electrocatalytic activity of a group of materials for HER, which are obtained by HTES in melts. Four samples of electrolytic materials were chosen for the study: tungsten, carbon, tungsten mono- and semi-carbides (WC and W2С). All samples were characterized in detail using X-ray diffraction (phase composition), SEM (morphology), Raman spectroscopy (structure of carbon phases), DTG (free carbon content).
 Based on the analysis of the obtained data, it was established that all samples can be used as catalysts: crystallites have a nanometer size and a large number of structural defects; morpho­logy provides increased surface area; tungsten carbide particles are covered with a layer of free carbon, which prevents oxidation of carbide to WO3, which has a lower catalytic acti­vity; carbon particles are nanosized (20–30 nm) and contain a large number of structural defects; tungsten carbide-based samples contain free carbon, which increases the specific surface area, but does not cause clogging of pores.
 Polarization measurements were carried out at room temperature at a polarization rate of 5 mV/s in a standard three-electrode cell with an Ag|AgCl reference electrode. 1N H2SO4 was used as a base solution, which was bubbled with high-purity argon. Onset potentials for all samples are -0.05 – -0.25 V (in order WC/C – W2C/WC/C – C – W). The overvoltage and Tafel slope were calculated and WC/C composite was shown to have the lowest values of -0.2 V and -75 mV, respectively.
 Electrolytic composite of tungsten carbide/carbon have demonstrated the best characteristics, so we plan to continue the development of synthesis method of carbide compounds, which will allow us to reveal even greater potential of carbide catalysts and pave the way for their wide application in catalytic processes.

Synthesis of Palladium Nanoparticles Supported over Fused Graphene-like Material for Hydrogen Evolution Reaction

The search for a clean abundant energy source brought hydrogen gas into the limelight; however, the explosive nature of the gas brings up issues with its storage. A way to mitigate this danger is through the storing of hydrogen in a hydrogen feedstock material, which contains a large percentage of its weight as hydrogen. Sodium borohydride is a feedstock material that gained a lot of attention as it readily reacts with water to release hydrogen. This study explored a novel composite composed of palladium nanoparticles supported on a sugar-derived fused graphene-like material support (PdFGLM) for its ability to catalyze the reaction of sodium borohydride in water. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were used to characterize and determine the size and shape of the catalyst used in this study. The XRD study detected the presence of palladium nanoparticles, and the EDS date confirmed the presence of 3% palladium nanoparticles. The TEM result shows the palladium nanoparticles of 5.5 nm incorporated to the graphene-like material layers. The composite contained approximately 3% palladium. In the hydrogenation reactions, it was observed that optimal reaction conditions included lower pHs, increased temperatures, and increased dosages of sodium borohydride. The reaction had the greatest hydrogen generation rate of 0.0392 mL min−1 mgcat−1 at pH 6. The catalyst was tested multiple times in succession and was discovered to increase the volume of hydrogen produced, with later trials indicating the catalyst becomes more activated with multiple uses. The activation energy of the reaction as catalyzed by PdFGLM was found to be 45.1 kJ mol−1, which is comparable to other catalysts for this reaction. This study indicates that this catalyst material has potential as a sustainable material for the generation of hydrogen.

One-Dimensional Selenidostannates Based on an Infrequent Tetrameric Cluster [Sn4Se12] Exhibiting Electro-Catalytic Properties.

The discovery of low-cost and efficient electro-catalytic materials for hydrogen evolution reaction (HER) is very desirable in hydrogen energy technology. Here, a new type of one-dimensional (1-D) organic hybrid selenidostannate [Ni(en)3]n[Sn2Se5]n (SnSe-1, en = ethylenediamine) with an in situ [Ni(en)3]2+ complex was achieved by the solvothermal reaction of Sn, Se, and NiCl2·6H2O in a mixed solvent of en and triethanolamine at 160 °C for 10 days. The crystal structure of SnSe-1 contains a unique 1-D [Sn2Se52-]n chain built up from the sharing-edge connection of a hitherto-unknown tetrameric [Sn4Se12] cluster, which is separated by discrete [Ni(en)3]2+ complexes. SnSe-1 is first combined with Ni nanoparticles supported on conductive porous Ni foam (NF) to constitute a Ni/SnSe-1/NF electrode as the HER electro-catalyst, displaying superior electro-catalytic activity in near-neutral conditions.

Hierarchical nanocomposite of cobalt sulfide nanoflakes-decorated reduced graphene oxide for enhancing the electrocatalytic hydrogen evolution reaction

The hydrogen evolution reaction (HER) driven by electrocatalytic water splitting is attaining prevalent attention for the manufacturing of clean and green hydrogen energy. Herein, we report the simple one-step hydrothermal synthesis of cobalt sulfide nanoflakes decorated with reduced graphene oxide (CoS/rGO) nanocomposites as an effective electrode material for HER. The CoS/rGO nanocomposites exhibited the rGO nanosheet-decorated hierarchically interconnected CoS nanoflakes structure. The CoS/rGO nanocomposites exhibited an excellent HER activity with a low overpotential of 371 mV and a small Tafel slope of 103 mV/dec. More interestingly, the catalytic stability of CoS/rGO nanocomposites is comparatively higher than the pristine CoS NFs. These results suggest that the facile nanocomposites of CoS/rGO could be a prominent catalytic material for effective green hydrogen production.

Ni(II) and Cu(II) grafted porphyrin-pyrene based conjugated microporous polymers as bifunctional electrocatalysts for overall water splitting

The development of a robust, sustainable and inexpensive bifunctional material for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) via electrochemical overall water splitting is very challenging and essential for energy generation and conversion processes. Herein, we have developed two 3d transition metals Ni(II) and Cu(II)-porphyrin based conjugated microporous polymeric electrocatalysts having high specific surface areas (1400 and 1350 m2g−1). Both catalysts showed good performance towards overall water splitting under alkaline pH conditions. These metal-coordinated porous polymers Ni-Por-Py and Cu-Por-Py are well characterized using different analytical instruments. Ni-Por-Py and Cu-Por-Py displayed a low overpotential of 213 mV and 250 mV, respectively to attend a current density of 10 mA/cm2 for HER using Ni-foam as substrate. The OER activity under alkaline condition with an overpotentials of 164 and 170 mV for Ni-Por-Py and Cu-Por-Py, respectively were achieved to drive a current density of 10 mA/cm2 under similar conditions. The excellent electrocatalytic activity of Ni-Por-Py and Cu-Por-Py could be attributed to the presence of transition metal coordinated porphyrin building blocks in the π-conjugated polymer skeletons, which facilitates the electron transfer processes along with inherent microporosity and high surface areas.

Electrodeposited Heterostructures of Cobalt Sulfide/Molybdenum Sulfide Trigger both Acidic and Alkaline HER

MoS2 has attracted significant attention as a non-platinum group electrocatalyst for the hydrogen evolution reaction (HER). There have been extensive efforts demonstrating that by doping MoS2 with various transition metals, such as Co, the HER activity of the catalyst is enhanced. In particular, this work has shown that various cobalt sulfide phases can act as a co-catalyst with MoS2. Here, we report on the electrodeposition of a c-CoSx/MoS2 heterostructure catalyst for the HER reaction in both acidic and alkaline conditions. Using Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy, it is demonstrated that depending on the precursor concentrations, various morphologies, grain size, and c-CoSx phases can be achieved, all of which have an impact on the activity and stability of the c-CoSx/MoS2 catalysts. The most promising catalyst composition demonstrated excellent stability in both acidic and alkaline conditions with low overpotentials to reach 10 mA cm−2 of 112 mV and 60 mV and with Tafel slopes of 113 mV dec−1 and 81 mV dec−1, respectively. This report demonstrates that the c-CoSx/MoS2 heterostructure is one of the most catalytically active materials for HER, especially in alkaline conditions.

Regulation the electrocatalytic performance of Ni-MOF derived material by extending the organic ligand

The overuse of fossil fuels has accelerated the desire for clean energy. Hydrogen energy has become an important energy on the world energy stage in the 21st century. Hydrogen production technology has also become the focus of attention. Based on the previous reported Ni-bib (bib ​= ​1,4-bis(1H-imidazole-1-yl) benzene), Ni-bibp (bibp ​= ​4,4′-bi(1H-imidazole-1-yl)-1,1′-biphenyl) with longer ligand was designed and synthesized by solvothermal method. Its molecular formula is {[Ni4(bibp)4(SO42−)4(H2O)8]}n. Ni-bibp-900 derived from high temperature pyrolysis can be used as bi-functional electrode material for HER (hydrogen evolution reaction) and UOR (urea oxidation reaction). For HER, the overpotential is −297mV at a current density of 10 ​mA ​cm−2. The Tafel slope of the Ni-bibp-900 is 153.3 ​mV·dec−1. For UOR, the overpotential is 1.4 ​V when the current density is 10 ​mA ​cm−2. The Tafel slope of the Ni-bibp-900 is 97.53 ​mV·dec−1. The performance of UOR and HER is better than that of Ni-bib-T. In addition, we also studied the effect of different doping amounts of zinc ions on HER. The results show that the HER performance is improved after doping zinc ion, which may be attributed to the sublimation of zinc ions during the pyrolysis process.

Boosting highly active defect MoV sites for amorphous molybdenum sulfide from catalyst-substrate effect toward efficient hydrogen evolution

Simultaneously achieving abundant active sites and high intrinsic activity is a major challenge to developing highly efficient MoSx-based materials for hydrogen evolution reaction (HER) since there might be a contradictory relationship between loading amounts and intrinsic activity of amorphous molybdenum sulfide (MoSx). Herein, we have for the first time demonstrated a strategy for the electrochemical oxidation of carbon cloth (CC) followed by mild acidification employing (NH4)2MoS4 as the precursor to boost highly active defect MoV sites (DMSs) for MoSx toward efficient HER. In our strategy, a high potential at the anode results in a high concentration of O-containing groups on the surface of CC, which favors loading [Mo3S13]2− clusters or MoSx on CC (MoSx/CC) for achieving abundant DMSs. Impressively, such oxidation does not disrupt the sp2 hybridized carbon of the substrate. Hence, the excellent conductivity of CC guarantees high intrinsic activity of the as-synthesized MoSx/CC samples. On the other hand, excessively high potential stimulates excessive growth and accumulation of [Mo3S13]2− clusters for further increasing loading amounts of MoSx. Nevertheless, such loading is at the expense of DMSs, indicating a great decrease in the quantity of active sites. Furthermore, excessive oxidation leads to unsatisfactory conductivity of CC, owing to breaking the sp2-conjugated system of CC. At the same time, the theoretical prediction and experimental investigation reveal that the intrinsic activity of DMSs will significantly decrease at excessively high potential. By regulating electrochemical potential to 1.8 V, a balance between the loading amounts of MoSx and intrinsic activity of MoSx/CC is achieved to boost highly active DMSs for efficient HER. Consequently, the optimal MoSx/CC exhibit the most excellent HER activity among all counterparts, accompanied by reliable stability. This work presents a new strategy for realizing abundant active sites with high intrinsic activity for MoSx-based materials toward efficient HER from the catalyst-substrate effect.

Pristine fullerene (C24) metals (Mo, Fe, Au) engineered nanostructured materials as an efficient electro-catalyst for hydrogen evolution reaction (HER): A density functional theory (DFT) study

The use of inexpensive, eco-friendly and earth-abundant transition metal-based carbon-based nanostructured materials for hydrogen evolution reaction (HER), has significantly increased. Hence, we examined the Mo-encapsulated, Fe-doped, and Au-decorated (AuFeMoC) dependent HER activity of C24 engineered nanostructured materials as an efficient electro-catalyst for HER using the density functional theory (DFT) approach at the PBE0/gen/6-311++G(d,p)/LanL2DZ level of theory. Our results revealed that AuFeMoC and FeMoC engineered surfaces show the strongest catalytic activity and are promising candidates for hydrogen production in Hydrogen evolution reaction (HER). Our calculations show that, after encapsulation, the Mo atom binds to the pristine C24 fullerene surface with a binding energy of −0.768 eV while stronger binding energy (−2.591 eV) is observed after doping the Mo-encapsulated fullerene (MoC) surface with Fe atom in the formation of engineered FeMoC. The calculated ΔGH values for H@AuFeMoC, H@FeMoC, H@MoC, and H@C is −0.0433, 0.1278, −0.0949, and −0.7920 eV, respectively. Based on the calculated ΔGH values, it is clear that H@AuFeMoC has the best catalytic activity of all engineered fullerene surfaces because it has ΔGH value closest to zero.

A Facile MOF Based Iron-Molybdenum Bimetallic Electrode Material Preparation for Hydrogen Evolution

Hydrogen energy has become the most potential energy source due to its high calorific value and environment-friendly combustion products. However, there are huge economic problems in hydrogen storage and transportation. Hydrogen can be prepared by catalysis in a way of reducing cost and speeding up speed which is the core idea of electrocatalytic water decomposition for hydrogen production. In this work, we developed an electrode material for Hydrogen evolution reaction (HER) bimetallic catalyst, and achieved that the hydrogen overpotential produced by acidic non-precious metal catalyst under acidic environment was only 275mV. More importantly, a good idea was provided for bimetallic co-catalysis of HER.

Heterointerface engineering of cobalt molybdenum suboxide for overall water splitting.

Highly active and earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are of great significance for sustainable hydrogen generation through alkaline water electrolysis. Here, with an aim to enhance the bifunctional electrocatalytic activity of cobalt molybdate towards overall water splitting, we demonstrate a simple method involving the modulation of the cobalt to molybdenum ratio and creation of phase-modulated heterointerfaces. Samples with varying Co/Mo molar ratios are obtained via a microwave-assisted synthesis method using appropriate starting precursors. The synthesis conditions are modified to create a heterointerface involving multiple phases of cobalt molybdenum suboxides (CoO/CoMoO3/Co2Mo3O8) supported on Ni foam (NF). Detailed electrochemical studies reveal that modulating the composition and hence the interface can tweak the bifunctional electrocatalytic activity of the material for HER and OER and thus improve the overall water splitting efficiency with very high durability over 500 h. To further evaluate the practical applicability of the studied catalyst in water splitting, an alkaline electrolyser is fabricated with the optimized cobalt molybdenum suboxide material (CMO-1.25) as a bifunctional electrocatalyst. A current density of 220 mA cm-2 @1.6 V and 670 mA cm-2 @1.8 V was obtained, and the device showed very good long-term durability.

Synthesis and photocatalytic activity evaluation of Au/g-C3N4 material for hydrogen evolution reaction

In this research, we report on the synthesis of Au/g-C3N4 material and study the effect of Au deposition on g-C3N4to optimize its photocatalytic performance. The presence of Au significantly enhances the light absorption and reduces the recombination rate of electron-hole pairs leading to improve the H2 evolution efficiency. The highly improved efficiency is also due to the efficient transfer of photoelectrons between the g-C3N4and Au molecules. The report indicates that the chemical reduction method to deposit gold nanoparticles on g-C3N4is an appropriate method with significant photocatalytic efficiency. The results open up another path for the synthesis of Au/g-C3N4for hydrogen evolution applications.

Construction of Ru, O Co‐Doping MoS2 for Hydrogen Evolution Reaction Electrocatalyst and Surface‐Enhanced Raman Scattering Substrate: High‐Performance, Recyclable, and Durability Improvement

AbstractMolybdenum disulfide (MoS2) is a promising non‐precious material for hydrogen evolution reaction (HER) electrocatalysts and surface‐enhanced Raman scattering (SERS) substrates. However, its inert basal plane, poor active sites, and limited stability hamper their commercial prospects. Herein, Ru, O co‐doped MoS2 (MSORx) for accelerating the charge transfer and building more active sites using one‐step hydrothermal method is designed to address these obstacles. The outstanding HER performances of the MSOR1 with low overpotentials at 10 mA cm−2 in both acidic (197 mV) and alkaline solution (43 mV), which even rivals that of commercial Pt/C. Meanwhile, this MSOR1 is also used as SERS substrate that has excellent sensitivity with the enhancement factor of 1.7 × 106. Additionally, label‐free detection of bilirubin using MSOR1 with a detection limit of 10−10 m has been demonstrated, also better than that of most previously reported semiconductors. Superior HER and SERS activity, universality in wide PH range and long‐term stability are achieved based on the introduction of Ru and O. This study provides guidance for the synthesis of highly active catalysts and SERS substrate, and holds considerable promise for low‐cost HER over the whole pH and clinical translation in accurate diagnosis of jaundice.

Empirical analysis and recent advances in metal-organic framework-derived electrocatalysts for oxygen reduction, hydrogen and oxygen evolution reactions

Developing ecofriendly electrocatalysts with high electrocatalytic performance is pivotal but remains a critical challenge in the efficient energy conversion technologies (including overall water splitting, hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). Metal−organic framework (MOF)-derived electrocatalyst materials have become a rapidly rising research area for solving the challenges associated with energy conversion technologies. This is due to unique features of MOF materials such as unique composition, structural diversity, large surface area, tunability, highly porous nature, and the secondary building units. They are often crystalline, ordered, and uniform solids, which are beneficial to engineering valuable features in rational ways. These advantages over other electrocatalysts have enabled MOFs to be notably utilized to overcome the sluggish kinetics and intrinsic thermodynamic barriers. Based on this, numerous attention has been devoted to the employment of various MOFs in HER, OER, ORR and water splitting. However, a comprehensive dataset showing the empirical analysis of these electrocatalysts for these applications becomes necessary to understand how closer or farther to industrial/commercial applications. The realization of this will enable the development of novel electrocatalysts and electrolyte media to successfully overcome the intrinsic barriers of meeting the industrial and commercial expectations in the field. To efficiently describe this empirical analysis, this study started by presenting the value of data with the momentous needs and reasons for this analysis. Since the study uses the electrocatalytic performance of different MOF-derived electrocatalysts, different experimental parameters for evaluating the performance of these MOF-derived were described. It critically compares different MOF-derived electrocatalysts based on the mechanistic criteria for energy-conversion involving rate-determining steps (RDS) using Tafel, Heyrovsky, and Volmer slopes of ∼30, ∼40, and ∼120 mV/dec, respectively. The overpotential or half-wave potential of these catalysts was also evaluated for further recommendations. A borderline of 50 h stability tests was drawn to gain more insight into the stability/durability performance and prospects of MOF-derived materials for HER, OER and ORR, which reflects that many of these materials performed below 50 h steady-state (durability) tests. This study further discussed some features of stability and stability under electrochemical conversion conditions. Also, in term of electrolytes for research on energy conversion, 1 M KOH, 0.1 M KOH, 0.5 M H2SO4, and 1 M KOH were prevalent, accounting for 73.53%, 88.24%, 58.49%, and 67.39% for OER, ORR, HER, and overall water splitting, respectively. To corroborate the empirical analysis, an overview of recent development on the electrocatalytic MOF-derived materials for HER, OER, and ORR was also discussed. Finally, the prospect of commercializing the MOF-derived electrocatalysts, the way forward in electrocatalysis, challenges and knowledge gap were discussed.

Oxygen vacancy-engineered Fe2O3 porous microspheres with large specific surface area for hydrogen evolution reaction and lithium-sulfur battery

Iron oxide (Fe2O3) with intrinsic catalytic activity and desirable theoretical capacity are expected to be promising active materials for hydrogen evolution reaction (HER) and lithium-sulfur (Li-S) batteries. Nevertheless, the sluggish electrons transfer accompanied with limited active sites impede their large-scale application. Generally, the silicon dioxide (SiO2) is employed as sacrificial template to regulate morphological structure of target products. However, selecting SiO2 as sacrificial shell may be a novel method to overcome the limitations and further optimize the performance of Fe2O3. Hence, a novel self-activation strategy along with reduction treatment is presented to prepare oxygen vacancy-engineered Fe2O3 porous microspheres featured with high specific surface area (SA-Fe2O3 (Ov)). Specifically, the simultaneously formation of rich oxygen vacancies and porous configuration could regulate electronic configuration, expose numerous active sites and enhance electrons transfer, leading to superior achievement for HER and Li-S batteries. Remarkably, the elaborately designed SA-Fe2O3 (Ov) achieves low overpotential and relatively small Tafel slopes. Furthermore, SA-Fe2O3 (Ov) holds great promise serving as sulfur host in the field of Li-S batteries with reversible capacity and impressive durability. This work contributes new insights into the self-activation strategy coupled with reduction synthesis of oxygen vacancy-engineered porous oxides with large specific surface area and raises the understanding of multifunctional energy applications.

Controlled Growth Interface of Charge Transfer Salts of Nickel-7,7,8,8-Tetracyanoquinodimethane on Surface of Graphdiyne

Controlled Growth Interface of Charge Transfer Salts of Nickel-7,7,8,8-Tetracyanoquinodimethane on Surface of Graphdiyne

Ni3Mo3N coupled with nitrogen-rich carbon microspheres as an efficient hydrogen evolution reaction catalyst and electrochemical sensor for H2O2 detection

Hydrogen evolution reaction (HER) and electrochemical analysis are two important fields of electrochemical research at present. We found that both HER and some electrochemical analytical reactions relied on the concentration of hydrogen ions (H+) in solution, so we intended to develop an electrode material that is sensitive to H+ and can be used for both HER and some electrochemical analyses. In this work, we synthesized Ni3Mo3N coupled with nitrogen-rich carbon microspheres (Ni3Mo3[email protected] MSs) as highly efficient electrode material for HER and detection of Hydrogen peroxide (H2O2), which plays an important role in physiological processes. Here the aniline was used as the nitrogen and carbon sources to synthesize Ni3Mo3[email protected] The Ni3Mo3[email protected] MSs showed high performance for HER in 1 M KOH solution with a small overpotential of 51 mV at 10 mA cm−2 and superior stability. For H2O2 detection, a detection limit of 1 μM (S/N = 3), sensitivity of 120.3 μA·mM−1 cm−2 and linear range of 5 μM–40 mM can be achieved, respectively. This work will open up a low-cost and easy avenue to synthesize transition metal nitrides coupled with N-doped carbon as bifunctional electrode material for HER and electrochemical detection.

Structural engineering of ultrathin vertical NbS2 on carbon cloth by chemical vapor deposition for hydrogen evolution reaction

Layered transition metal dichalcogenides (TMDs) with rich chemistry and diverse properties are considered promising candidates for applications in nanoscale electronics and energy conversion. Among the wide range of TMDs, niobium dichalcogenides (NbS[Formula: see text] are ubiquitously considered to be a great promise material for hydrogen evolution reaction (HER) due to its metallic 2D feature with good conductivity. However, a few reports focus on the systematic structural optimization of NbS2 nanosheets on conductive substrates by chemical vapor deposition (CVD) towards HER. Here, vertical NbS2 nanoflowers are designed and constructed on carbon cloth using CVD. Systematic growth experiments are carried out to investigate the structure variation of the nanostructures. By tuning the growth temperature, the architecture with dense exposed basal planes is achieved, which exhibits highly structure-sensitive properties for HER. The results show NbS2 microflowers with maximized edge and plane sites exhibited optimal catalytic performance. The growth mechanism of NbS2 nanoplates on carbon cloth is further explored. These findings provide a guideline for optimization of microstructure and electrocatalytic activity for NbS2 and broaden our vision for improving HER performance of novel 2D TMDs.