Hydrogen Evolution Process Research Articles

Electrochemical and piezocatalysis properties of Bi0.5(Na0.9K0.1)0.5TiO3 ceramic

Piezocatalysis activity was examined for poled and unpoled Bi0·5(Na0·9K0.1)0.5TiO3 (BNKT) ceramic. BNKT was synthasized using solid state routes and was thoughly characterized using X-ray diffraction, Scanning electron microscopy,and XPS. BNKT was examined for piezocatalysis inder ultrasonication for Rhodamine B (RB) dye. Poling was performed using Corona poling setup and piezoelectric nature was evaluated using d33. d33 was found to be ±45pC/N for sintered sample. The effect of electric poling was significant in view of dye degradation performance. Poled BNKT sample degraded ∼90% the RB dye solution in 180 min which was segnificanly higher than that of unpoled sample. The influence of electric poling on the oxygen reduction and hydrogen evolution process in alkaline fuel cells and electrolyzer is also reported.

Induction-Diffusion-Adsorption Process of Malachite Green for Cobalt Superconformal Electrodeposition

Cyclic voltammetry (CV), chronopotentiometry and quartz crystal microbalance were used to study the effect of Malachite Green (MG) on bottom-up growth of cobalt. The addition of MG not only inhibited the reduction of Co2+ but also accelerated the hydrogen evolution process. The metal reduction process was enhanced as well as the current efficiency was higher with the increase of pH. The bottom-up growth of cobalt can be achieved with the potential of −1.20 V. Induction-diffusion-adsorption superconformal electrodeposition mechanism was proposed to illustrate the synergistic effect of MG and pH on the growth of cobalt. On one hand, the MG concentration gradient and pH gradient could be formed to achieve a growth rate difference within blind vias so as to obtain bottom-up growth (diffusion-adsorption effect). On the other hand, the growth rate difference was intensified due to the accelerating effect of MG on HER so as to boost the cobalt superfilling (induction effect).

Electrocatalytic performance of copper selenide as structural phase dependent for hydrogen evolution reaction

A cost-effective, efficient and stable electrocatalyst is a remarkable and significant prospect for hydrogen evolution reaction. By adjusting the copper contents, the Hexagonal and Tetragonal phases of the copper selenide have been synthesized using the solvo-hydrothermal process. Hexagonal phased-based copper selenide has exhibited a greater current density than the Tetragonal phase. However, the augmented structure, lower Gibbs Free energy, greater electrical conductivity and electrochemical surface promoted the electrocatalytic behavior of Hexa-CuSe-1.04 nanosheets. Hexa-CuSe-1.04 nanosheets exhibit a good overpotential of 61 mV at the state of art current density of 10 mAcm−2 along with Tafel slope of 59 mV dec−1 in 1 M KOH, which is better than the other Hexagonal phase structure, Hexa-CuSe-1.67 nanosheets and Tetra-Cu2Se-1.30 phase of the copper selenides. The electrocatalyst Hexa-CuSe-1.04 maintains the current density for a long duration and exhibits a similar linear sweep voltammetry curve in 1 M KOH during the chronoamperometry test. Moreover, Hexa-CuSe-1.04 nanosheets show a good Tafel slope of 26 mV dec−1 with a good turnover frequency of 72.40 m s−1 in 0.5 M H2SO4 and follow the Tafel phenomenon. Optimized density functional theory reveals that Hexa-CuSe-1.04 exhibits the lower Gibbs of 1.04 eV, free energy, which promotes the desorption and recombination process of the active hydrogen atoms at the active sites and enhanced the hydrogen evolution process. All results indicate the leading potential application of the Hexagonal phase of Hexa-CuSe-1.04 for hydrogen evolution reaction.

Fullerene Lattice‐Confined Ru Nanoparticles and Single Atoms Synergistically Boost Electrocatalytic Hydrogen Evolution Reaction

AbstractThe design and construction of electrocatalysts with high efficiency, low cost and large current output suitable for industrial hydrogen production is the current development trend for water electrolysis. Herein, a lattice‐confined in situ reduction effect of the 3D crystalline fullerene network (CFN) is developed to trap Ru nanoparticle (NP) and single atom (SA) via a solvothermal‐pyrolysis process. The optimized product (RuNP‐RuSA@CFN‐800) exhibits outstanding electrocatalytic performance for alkaline hydrogen evolution reactions. To deliver a current density of 10 mA cm−2, the RuNP‐RuSA@CFN‐800 merely required an overpotential of 33 mV, along with a robust electrocatalytic durability for 1400 h. Even at large current densities of 500 and 1000 mA cm−2, the overpotentials are only 154 and 251 mV, respectively. Density function theorey calculation results indicated that the electronic synergetic effect between Ru NP and SA enable to regulate the charge distribution of RuNP‐RuSA@CFN‐800 and reduce the Gibbs free energy of intermediate species for water dissociation process, thereby accelerating the hydrogen evolution process. Moreover, the robust CFN matrix render this strategy patulous to other transition metals, e.g., Cu, Ni, and Co. The present study provides a new clue for the construction of novel electrocatalyst in the field of energy storage and conversion.

Chemical and Electrochemical Studies on Expired Lioresal Drugs as Corrosion Inhibitors for Carbon Steel in Sulfuric Acid

Lioresal is a muscle relaxer and an antispasmodic agent, known as Lioresal. The active ingredient is β-(Aminomethyl)-p-chlorohydrocinnamic acid, a racemic mixture of the R,(-) and S, (+) isomers. It affects directly the spinal cord with adverse effects including drowsiness, dizziness, weakness, fatigue, headache, trouble sleeping, nausea and vomiting, urinary retention, or constipation. Therefore, the accumulation of expired or unused Lioresal in our home is so dangerous and harmful for our children. The present work introduces an idea for using expired Lioresal as a corrosion inhibitor for steel in 1.0 M H2SO4. The effect of both concentration and temperature were studied. The inhibition efficiency was found to increase with concentration and decreased with rising temperature. Chemical, electrochemical, and analytical techniques, namely, gravimetric, thermometric, gasometric, acidimetric, AAS, and potentiodynamic polarization were used to evaluate the inhibition action of the expired Lioresal drugs. The inhibition performance is due to the adsorption and adhesion of drugs constituent molecules on the steel surface. The adsorption was found to obey Langmuir isotherm. The surface area available for the anodic dissolution of iron and cathodic hydrogen evolution process diminishes without changing the reaction mechanism. The values of Ecorr. readings slowly decrease to negative values, showing that these inhibitors are mixed-type inhibitors mainly cathodic inhibitors. The data obtained from different techniques are in good agreement with each other. Electrochemical and analytical Techniques are efficient and accurate in the determination of the corrosion rate and inhibition performance of expired drugs in an aqueous medium.

Insights into the mechanisms of H2S adsorption and dissociation on CdS surfaces by DFT-D3 calculations

The adsorption and dissociation of H2S on CdS surfaces is investigated using dispersion-corrected density functional theory (DFT-D3) to provide quantum-level insights into their (photo)catalytic performance for H2S splitting. Calculations of structural parameters, electronic properties and energies of intermediates adsorption on perfect CdS surfaces indicate that the (110) facet is the most stable surface, while the most active surface (100) is quickly covered by sulfur formed during the reaction, unfavorable for catalyst stability and reuse. Calculations of CdS (110) surfaces with an S vacancy demonstrate that the vacancy serves as an electron donor center and atomic S∗ capture center, favoring the adsorption of dissociative species, and significantly reducing the energy barriers and reaction energies for the hydrogen evolution process, hence increasing the CdS surface catalytic performance. These theoretical results complement and reinforce available experimental studies, guiding the rational design of efficient photocatalysts for hydrogen production from H2S splitting.

Multifold Fermions and Fermi Arcs Boosted Catalysis in Nanoporous Electride 12CaO·7Al2 O3.

Topological materials have been recently regarded as ideal catalysts for heterogeneous reactions due to their surface metallic states and high carrier mobility. However, the underlying relationship between their catalytic performance and topological states is under debate. It has been discovered that the electride 12CaO·7Al2 O3 (C12A7:4e- ) hosts multifold fermions and Fermi arcs on the (001) surface near the Fermi level due to the interstitial electrons. Through the comparison of catalytic performance under different doping and strain conditions, based on the hydrogen evolution process, it has been demonstrated that the excellent catalytic performance indeed originates from topological properties. A linear relationship between the length of Fermi arcs, and Gibbs free energy (ΔGH* ) has been found, which not only provides the direct evidence to link the enhanced catalytic performance and surface Fermi arc states, but also fully clarifies the fundamental mechanism in topological catalysis.

Cobalt metal–organic framework derived cobalt–nitrogen–carbon material for overall water splitting and supercapacitor

Metal-organic frameworks (MOFs) have been the subject of intensive structural tuning via methods like pyrolysis for superior performance in electrocatalytic oxygen and hydrogen evolution processes (OER and HER) and supercapacitors. Here, a Co-MOF based on 2-methylimidazole was synthesized using a precipitation approach, and its electrochemical characteristics were tuned via pyrolysis at different temperatures, including 600, 700, and 800 °C. Characterization findings corroborated the formation of Co–N–C moieties from Co-MOF, and XPS analyses indicated that 700 °C was the optimal temperature for achieving a high density of Co–N–C moieties. The optimized Co-MOF-700 sample displayed remarkable HER and OER performance in terms of lower overpotentials of 75 mV and 370 mV as well as small Tafel slopes of 118 mV/dec and 79 mV/dec, respectively. Furthermore, at a current density of 1 A/g, the Co-MOF-700 sample had a specific capacitance of 210 F/g. The enhanced electrochemical properties of Co-MOF-700C as compared to other samples can be attributed to the availability of a high density of Co–N–C sites for catalytic reaction and its porous architecture. This study will expand the knowledge of how compositional and morphological changes in MOFs affect their utility in energy conversion and storage applications.

ALD-Deposited NiO Approaches the Performance of Platinum as a Hydrogen Evolution Cocatalyst on Carbon Nitride

The photocatalytic hydrogen evolution reaction is one of the most promising approaches to utilize solar energy and produce hydrogen as an alternative energy source to traditional fossil fuels. In this work, we focused on further exploring the cocatalyst potential of the transition metal nickel and prepared nickel oxide/carbon nitride (NiO/CNx) heterojunctions through thermal polymerization as well as plasma-enhanced atomic layer deposition (PEALD). The optimal NiO loading thickness on the surface of the CNx was found to be 6.5 nm, prepared from 65 cycles of ALD. This NiO(65)/CNx had a photocatalytic hydrogen evolution rate of 3.9 μmol h–1 in a 2 mg mL–1 aqueous photocatalyst solution (195 μmol h–1 g–1), corresponding to an AQY of 3.1% and exhibiting 54% of the activity of 3 wt % Pt/CNx under 405 nm light illumination with a sacrificial reagent. A 3 wt % Ni/CNx prepared through a photodeposition process from a dispersion of CNx and simple NiCl2 had a photocatalytic hydrogen evolution rate of 2.8 μmol h–1 (140 μmol h g–1) and an AQY of 2.2% with 2 mg mL–1 photocatalyst in the reactant solution, corresponding to 39% of the activity of 3 wt % Pt/CNx. An induction period at the beginning of the hydrogen evolution process was found in all Ni-based photocatalysts, which we related to a Ni in situ photoreduction from NiII to Ni0 and the reverse reaction. In addition, the reproducibility of the induction period even in an oxygen-free environment suggests that electrons flow back from reduced Ni species to CNx under dark conditions. Furthermore, a large population of trap states was detected in the bulk CNx materials via photoinduced absorption spectroscopy, and the trapping severely hinders cocatalysts (even the benchmark Pt cocatalyst) from extracting charges from CNx for subsequent interfacial redox reactions. We conclude that not only does the surface/interface engineering of the photocatalyst/catalyst heterojunctions need to be considered but also trap states in CNx that severely limit the transfer of photogenerated charges to cocatalysts.

Understanding the injection process of hydrogen on Pt1-TiO2 surface for photocatalytic hydrogen evolution

Observing and understanding the surface changes of catalysts during reactive process can provide imperative insights into the mechanism study. Here, we investigated several different surface behaviors based on Pt/TiO2 catalysts during photocatalytic hydrogen evolution process. We found the single Pt atoms on TiO2 surface (Pt1-TiO2) could induce the hydrogen injection into the TiO2 subsurface to generate self-hydrogenated shell. This hydrogenated configurations in subsurface can serve as dominated locations for hydrogen formation and desorption process, which greatly boost the catalytic rate. Electron energy loss spectroscopy and in-situ experiments further confirm the as-formed amorphous shell contains reduced Ti ions and oxygen defects. Density functional theory calculations verify that high-concentrated hydrogenated shell on Pt1-TiO2 surface can significantly reduce the desorption energies of H2 formation. Our discovery thus provides important insight for the fundamental understanding of hydrogen evolution reactions and is also expected to open up a new way to design highly effective photocatalysts.

Progress on Electrodeposition of Metals and Alloys Using Ionic Liquids as Electrolytes

The electrodeposition process of metals and their alloys is widely used in the automotive, space, electronics, computing, jewelry, and other consumer items industries. Over the years, the search for new coatings with more suitable characteristics for their application led to the use of ionic liquids (ILs) as electrolytic solutions. In addition to having good conductive properties, the growing interest in these solvents has environmental appeal due to their low toxicity. Furthermore, the ability of these electrolytes to dissolve compounds containing less soluble metals makes them potential substitutes for environmentally harmful solvents. In this sense, this review describes the current state and the innovations concerning the electrodeposition of metals and alloys using ILs as electrolytes in the last five years. Metals were classified into five groups (common, light, noble, rare earth, and others), highlighting not only the ability to form a smooth, homogeneous, and anti-corrosive deposit, but also the reactive capacity of metals in hydrogen evolution and catalytic processes.

Pulsed laser induced synthesis of graphitic carbon nitride-cadmium selenide nanocomposite for photo-catalytic degradation of organic dyes, and electro-catalytic hydrogen evolution reaction

Graphitic carbon nitride (g-C3N4) is a visible light active photo-catalyst, but its photo-catalytic efficiency is hampered by rapid recombination of the photo-induced charge carriers in g-C3N4. This adverse charge recombination of g-C3N4 is efficiently retarded by compositing g-C3N4 with cadmium selenide (CdSe). The energy band gap of CdSe is narrower than that of g-C3N4, and also its band positions are compatible with g-C3N4 in order to carry out the lateral intersystem crossing of the photo-induced electrons from the conduction band of g-C3N4 to that of CdSe. In this work, g-C3N4/CdSe nanocomposites with four different CdSe mass loading (1%, 2.5%, 5%, and 10%) were synthesized by pulsed laser induced method, where laser fragmentation (LFL), and laser defect engineering (LDL) are the underlying processes. The structural, morphological, and elemental characterizations using XRD, TEM, FE-SEM, and EDX confirmed the proper anchoring of CdSe nanoparticles on the g-C3N4 polymeric surface. The modified band structure in the g-C3N4/CdSe nanocomposite not only enhanced the visible light absorption, but also effectively retarded the photo-induced charge recombination, which are reflected in the optical absorption spectra, and the photoluminescence spectra respectively. Photo-catalytic degradations of Rhodamine B (RhB), and methylene blue (MB) dyes under visible light in the presence of four different variants of g-C3N4/CdSe nanocomposites were estimated, and bench marked with pure g-C3N4. As anticipated, the photo-catalytic degradation efficiency of all the variants of g-C3N4/CdSe nanocomposites is significantly higher than that with pure g-C3N4. The highest photo-catalytic degradation rate constant of 0.0222 min−1, 0.0178 min−1 respectively for MB and RhB were achieved using g-C3N4/CdSe nanocomposite with 2.5% CdSe mass content. As a second application, g-C3N4/CdSe nanocomposite was also used in the electrocatalytic hydrogen evolution process in the acidic medium. Thin this study, the observed over potential recorded was lower for g-C3N4/CdSe nanocomposite than that with pure g-C3N4, indicating the higher hydrogen evolution capability of this nanocomposite as the electro-catalyst.

Tailored nitrogen-defect induced by diels-alder reaction for enhanced electrochemical hydrogen evolution reaction

Electrocatalytic water splitting in an alkaline medium is recognized as the promising technology to sustainably generate clean hydrogen energy via hydrogen evolution reaction (HER), while the sluggish water dissociation and subsequent *H adsorption steps greatly retarded the reaction kinetics and efficiency of the overall hydrogen evolution process. Whilst nitrogen (N)-doped carbon-based materials are attractive candidates for promoting HER activity, the facile fabrication and gaining a deeper insight into the electrocatalytic mechanism are still challenging. Herein, inspired by the Diels-Alder reaction, we precisely tailored six-membered pyridinic N and five-membered pyrrolic N sites at the edge of the carbon substrates. Comprehensive analysis validates that the participation of pyridinic N (electron-withdrawing) and pyrrolic N (electron-releasing) will induce the charge rearrangements, and further generate local electrophilic and nucleophilic domains in adjacent carbon rings, which guarantees the occurrence of water dissociation to generate protons and the subsequent adsorption of *H intermediates through electrostatic interactions, thereby facilitating the overall reaction kinetics. To this end, the optimal NC-ZnCl2-25 % electrocatalysts present excellent alkaline HER activity (η10 = 45 mV, Tafel slop of 37.7 mV dec-1) superior to commercial Pt/C.

Cobaltous selenide/g-C3N4 heterojunction photocatalyst based on double-electron migration mechanism promotes hydrogen production and tetracycline hydrochloride degradation

Regulating photogenerated charge carrier transfer kinetics in multi-component heterostructure by surface-interface design is of great significance for accelerating efficiently photocatalytic hydrogen evolution reaction. Herein, a novel binary CoSe2/CNNS composite is successfully fabricated by a successive high-temperature calcination method of g-C3N4 followed by in-situ hot injection process of CoSe2 for the first time. The optimal 7.5% CoSe2/CNNS heterostructure reaches moderate hydrogen production rate of 1386.8 μmol·g−1·h−1 and exhibits good mineralization efficiency for tetracycline hydrochloride (40.6%) within 120 min under light irradiation, respectively. The photogenerated charge migration behaviors, the generation process and function of various radical species (H2O2, ·OH and ·O2−) are detailedly analyzed. Moreover, photocatalytic hydrogen evolution reaction process and the intermediates and active species for tetracycline hydrochloride degradation can also be discussed. Such significantly enhanced photocatalytic activity can be resulting from good light trapping ability, rapid photocarriers transfer efficiency and accelerated H2O2 decomposition ability via a continuous two-electron/two-step reduction route. This work provides an effective strategy to control and understand the charge migration kinetics as well as to suppress H2O2 production during photocatalytic hydrogen evolution process.

Efficient Photocatalytic Hydrogen Production over NiS-Modified Cadmium and Manganese Sulfide Solid Solutions.

In this work, new photocatalysts based on Cd1-xMnxS sulfide solid solutions were synthesized by varying the fraction of MnS (x = 0.4, 0.6, and 0.8) and the hydrothermal treatment temperature (T = 100, 120, 140, and 160 °C). The active samples were modified with Pt and NiS co-catalysts. Characterization was performed using various methods, including XRD, XPS, HR TEM, and UV-vis spectroscopy. The photocatalytic activity was tested in hydrogen evolution from aqueous solutions of Na2S/Na2SO3 and glucose under visible light (425 nm). When studying the process of hydrogen evolution using an equimolar mixture of Na2S/Na2SO3 as a sacrificial agent, the photocatalysts Cd0.5Mn0.5S/Mn(OH)2 (T = 120 °C) and Cd0.4Mn0.6S (T = 160 °C) demonstrated the highest activity among the non-modified solid solutions. The deposition of NiS co-catalyst led to a significant increase in activity. The best activity in the case of the modified samples was shown by 0.5 wt.% NiS/Cd0.5Mn0.5S (T = 120 °C) at the extraordinary level of 34.2 mmol g-1 h-1 (AQE 14.4%) for the Na2S/Na2SO3 solution and 4.6 mmol g-1 h-1 (AQE 2.9%) for the glucose solution. The nickel-containing samples possessed a high stability in solutions of both sodium sulfide/sulfite and glucose. Thus, nickel sulfide is considered an alternative to depositing precious metals, which is attractive from an economic point of view. It worth noting that the process of photocatalytic hydrogen evolution from sugar solutions by adding samples based on Cd1-xMnxS has not been studied before.

Two-Dimensional Transition Metal-Hexaaminobenzene Monolayer Single-Atom Catalyst for Electrocatalytic Carbon Dioxide Reduction.

Electrocatalytic reduction of CO2 to valuable fuels and chemicals can not only alleviate the energy crisis but also improve the atmospheric environment. The key is to develop electrocatalysts that are extremely stable, efficient, selective, and reasonably priced. In this study, spin-polarized density function theory (DFT) calculations were used to comprehensively examine the catalytic efficacy of transition metal-hexaaminobenzene (TM-HAB) monolayers as single-atom catalysts for the electroreduction of CO2. In the modified two-dimensional TM-HAB monolayer, our findings demonstrate that the binding of individual metal atoms to HAB can be strong enough for the atoms to be evenly disseminated and immobilized. In light of the conflicting hydrogen evolution processes, TM-HAB effectively inhibits hydrogen evolution. CH4 dominates the reduction byproducts of Sc, Ti, V, Cr, and Cu. HCOOH makes up the majority of Zn's reduction products. Co's primary reduction products are CH3OH and CH4, whereas Mn and Fe's primary reduction products are HCHO, CH3OH, and CH4. Among these, the Ti-HAB reduction products have a 1.14 eV limiting potential and a 1.31 V overpotential. The other monolayers have relatively low overpotentials between 0.01 V and 0.7 V; therefore, we predict that TM-HAB monolayers will exhibit strong catalytic activity in the electrocatalytic reduction of CO2, making them promising electrocatalysts for CO2 reduction.

Kinetically Controlled Mn Doping Effect on Composition Tuned CoMn Hydroxide Nanoflakes for Overall Water Splitting Application

AbstractThe research on cobalt‐based bimetallic hydroxides has led to their emergence as an effective electrocatalyst for oxygen (OER) and hydrogen evolution processes (HER) to split water and replace state‐of‐the‐art efficient noble metals. It is imperative to conduct both the OER and HER in the same electrolyte, hence it is necessary to adjust the material‘s characteristics to be compatible for this application. Due to the Co3+ active site, Co(OH)2 is electrochemically oxidized to CoOOH and exhibits outstanding OER kinetics. The incorporation of Mn into the cobalt hydroxide matrix increases the surface area while balancing the ratio of *OH to *O radicals to increase electrocatalytic activity. The complementary effects of the two metal hydroxides (Co and Mn) reveal a fresh perspective on the next‐generation electrocatalyst. The OER and HER reactions are both optimized using an easy electrodeposition method. The best HER and OER as two‐electrode electrolyzers displayed a cell voltage of 1.69 V at 10 mA/cm2 in alkaline electrolyte. Interestingly, when the state of art material Pt deposited on nickel foam substrate used for HER and the best CoMn hydroxide used for OER exhibits a cell voltage of only 1.55 V to drive the current density of 10 mA/cm2.

Enhanced hydrogen evolution performance by nanoarchitectonics of Fe/Co alloy electrode beyond Fe/Co/Ni alloy electrode

With the increasing global energy demand, hydrogen production from electrolytic water became the main way to prepare efficient and clean hydrogen energy. Transition metal catalyst were promising hydrogen evolution catalyst for low cost, stable performance and high catalytic activity. In this study, Fe–Co–Ni, Co–Fe, Ni–Fe and Co–Ni alloy electrodes were prepared by electrodeposition. Among the four alloys, Co–Fe showed the best hydrogen evolution performance. The surface of Co–Fe alloy electrode coating was composed of round small particles of different sizes closely combined to form a large complex. In the alloy, Co was accounted for 62.2% and Fe was accounted for 37.8%. The increase of Co content increased the specific surface area of the electrode, provided a large number of catalytic active sites, and improved the hydrogen evolution performance. In the Co–Fe alloy electrode, Fe was existed in the form of Fe2+ and Fe3+, Co was existed in the form of Co2+. The electrochemical test results showed that Co–Fe alloy electrode had the highest electrocatalytic activity. Since the conductivity of cobalt hydroxide and iron hydroxide generated in the strong alkali environment, which was stronger than that of nickel hydroxide, the internal resistance of the Co–Fe alloy electrode in the hydrogen evolution process was reduced. Under the same conditions, the Co–Fe alloy electrode needed only 1483 mV overpotential to drive a current density of 0.1 A/cm2. The Tafel slope of Co–Fe alloy electrode was the smallest, only 144.04 mV/dec, and the electron transmission efficiency was the highest. Co–Fe alloy electrode had the lower electron conduction resistance and better electrochemical hydrogen evolution performance.

Enhanced Electrocatalytic Activity for Hydrogen Evolution Reaction from Electrophoretically-Deposited BiSbSe3 Nanoparticles

For the development of renewable energy conversion and storage systems, it is vital to investigate earth-abundant, noble-metal-free, and highly efficient electrocatalysts for the hydrogen evolution process (HER). Platinum and other precious metals-based electrocatalysts show better HER activity in acidic conditions than other electrocatalysts due to their fast kinetics and lower Tafel slope.[1] However, because they are rare and costly, they are challenging to deploy in practical applications. As a result, there has been an ongoing search for low-cost and earth-abundant materials that may be used as an efficient alternative for platinum-based electrocatalysts, with the goal of developing more cost-effective and inexpensive H2 manufacturing processes. The layered 2D nanomaterials have sparked a lot of scientific attention because of their tremendous potential for both fundamental and practical investigations. Natural minerals of the group V-VI (V = Bi, Sb; VI = S, Se) have exceptional optical and electrical characteristics.[2] Because of their availability, low cost, and tunable characteristics, antimony/bismuth-based chalcogenides are garnering a lot of attention as potential candidates as electrocatalysts for acidic HER. We have shown an efficient and straightforward approach for the electrochemical exfoliation of BiSbSe3 nanostructures from the ball-milled BiSbSe3 sample; the process parameters were adjusted in terms of time and applied voltage. Furthermore, a simple and straightforward electrophoretic deposition process was used to synthesize BiSbSe3 nanoparticles from exfoliated BiSbSe3 nanostructures. A DC voltage was supplied between the two inert electrodes in an aqueous electrolyte for the electrophoretic deposition of BiSbSe3 nanostructures directly onto a gold substrate. Charged particles or sheets suspended in the electrolyte are activated to migrate toward the electrode and deposit when a voltage is applied. The BiSbSe3 nanoparticles were deposited onto the positive electrode because the exfoliated BiSbSe3 nanostructures in water had a negative zeta potential. BiSbSe3 nanostructures prepared through electrochemical exfoliation method are electrophoretically deposited onto the gold substrate to obtain BiSbSe3 nanoparticles, were investigated as active electrocatalysts for HER in 0.5 M H2SO4 solution using a three-electrode set up. The optimized BiSbSe3 catalyst (10V10M-Au-7.5) is identified as highly active HER activity, having a low overpotential of 72 mV @ 10 mA cm−2 and a low Tafel slope of 31.6 mV dec-1, which far better than the antimony/bismuth chalcogenide system and very close to the state-of-the-art Pt/C catalyst. We demonstrate that the electrocatalytic HER activity is enhanced by highly active edge sites, large available surface active sites, defects created and partial oxidization of material during electrodeposition, and a synergistic effect between BiSbSe3 and the substrate.

A Nanoneedle Ni12P5 Array for Hydrogen Evolution Reaction with High Efficiency over a Wide pH Range

AbstractTransition metal phosphides (TMP) with high conductivity and better H* intermediate adsorption energy have attracted great attention in hydrogen evolution process. Herein, a Ni12P5 nanoneedle array was synthesized by a facile one‐step phosphorization method. As expected, the obtained Ni12P5 nanoneedle arrays exhibits high HER performance, and low overpotentials of 59, 117, and 148 mV are need to drive hydrogen evolution at current densities of 10, 50, and 100 mA cm−2 in 1 mol/L KOH electrolyte, respectively. Meanwhile, the obtained electrode exhibits excellent hydrogen evolution activity in both acidic and neutral media. Excellent electrochemical performances demonstrate that the nickel phosphide could be a candidate for high‐performance water electrolysis over a wide pH range.