Phase Engineering of Dual Active 2D Bi2O3-based Nanocatalysts for Alkaline Hydrogen Evolution Reaction Electrocatalysis

Hydrogen evolution from electrochemical water splitting under alkaline conditions is an ongoing challenge for the requirement of a simultaneous balance to be achieved between the water dissociation step and the...

Electrochemical Reaction and Dissociation of Glycerol on PdAu Surface Catalyst

Direct Glycerol Fuel Cell is one of the alternative energy that can produce electricity without burning. The production of electricity without combustion can reduce the use of fossil fuel as well as reduce environmental pollution. A new catalyst of PdAu has been synthesized in this study to increase the activity of the glycerol oxidation reaction. Morphologies analysis was performed on CNF-supported synthesized PdAu. FESEM and TEM image show the PdAu supported on the CNF surface. Both PdAu and CNF has a diameter size of 4-6 nm and 80-130 nm, respectively. In CV analysis, PdAu/CNF has produced an oxidation peak and current density at -0.9 V vs. SCE and 70 mA/cm2, respectively. Each mechanism of glycerol dissociation step during glycerol oxidation, different atomic active sites are required in PdAu. For example, for glycerol adsorption, Au atom as an active site while for *C3H7O3 requires Pd atom and Au atom as the active site. The Au catalyst model shows better adsorption as Au/CNF has a slightly more negative oxidation peak than PdAu. Nevertheless, the Au catalyst showed less durability compared to PdAu.

Targeted Assembly of Ultrathin NiO/MoS2 Electrodes for Electrocatalytic Hydrogen Evolution in Alkaline Electrolyte

The development of non-noble metal catalysts for hydrogen revolution in alkaline media is highly desirable, but remains a great challenge. Herein, synergetic ultrathin NiO/MoS2 catalysts were prepared to improve the sluggish water dissociation step for HER in alkaline conditions. With traditional electrode assembly methods, MoS2:NiO-3:1 exhibited the best catalytic performance; an overpotential of 158 mV was required to achieve a current density of 10 mA/cm2. Further, a synergetic ultrathin NiO/MoS2/nickel foam (NF) electrode was assembled by electrophoretic deposition (EPD) and post-processing reactions. The electrode displayed higher electrocatalytic ability and stability, and an overpotential of only 121 mV was needed to achieve a current density of 10 mA/cm2. The improvement was ascribed to the better catalytic environment, rather than a larger active surface area, a higher density of exposed active sites or other factors. DFT calculations indicated that the hybrid NiO/MoS2 heterostuctured interface is advantageous for the enhanced water dissociation step and the corresponding lower kinetic energy barrier—from 1.53 to 0.81 eV.

Electrochemically Induced In-Situ Generated Co(OH)2 Nanoplates to Promote the Volmer Process Toward Efficient Alkaline Hydrogen Evolution Reaction

<p>Hydrogen production via alkaline water electrolysis is of significant interest. However, the additional water dissociation step makes the Volmer step a relatively more sluggish kinetics and consequently leads to a slower reaction rate than that in acidic solution. Herein, we demonstrate an effective strategy that Co(OH)₂ can promote the Volmer process by accelerating water dissociation and enhance the electrocatalytic performance of CoP toward alkaline hydrogen evolution reaction. The Co(OH)₂ nanoplates are electrochemically induced in-situ generated to form a nanotree-like structure with porous CoP nanowires, endowing the hybrid electrocatalyst with superior charge transportation, more exposed active sites, and enhanced reaction kinetics. This strategy may be extended to <a></a><a>other phosphides and chalcogenides </a>and provide insight into the design and fabrication of efficient alkaline HER catalysts.</p>

Electrochemically Induced In-Situ Generated Co(OH)2 Nanoplates to Promote the Volmer Process Toward Efficient Alkaline Hydrogen Evolution Reaction

<p>Hydrogen production via alkaline water electrolysis is of significant interest. However, the additional water dissociation step makes the Volmer step a relatively more sluggish kinetics and consequently leads to a slower reaction rate than that in acidic solution. Herein, we demonstrate an effective strategy that Co(OH)₂ can promote the Volmer process by accelerating water dissociation and enhance the electrocatalytic performance of CoP toward alkaline hydrogen evolution reaction. The Co(OH)₂ nanoplates are electrochemically induced in-situ generated to form a nanotree-like structure with porous CoP nanowires, endowing the hybrid electrocatalyst with superior charge transportation, more exposed active sites, and enhanced reaction kinetics. This strategy may be extended to <a></a><a>other phosphides and chalcogenides </a>and provide insight into the design and fabrication of efficient alkaline HER catalysts.</p>

Tuning the Water Reduction Through Controlled Nanoconfinement Within an Organic Liquid Matrix

<p>The growing hydrogen-economy requires accelerating the hydrogen evolution reaction. The water dissociation step (Volmer step) has been proposed as a main kinetic limitation, but the mechanisms at play in the electrochemical double-layer are poorly understood. This is due to the ambivalent role of water: it acts both as a reactant and as a solvent. Here we propose to confine water inside an organic liquid matrix in order to isolate the sole role of water as a reactant. We observe the formation of aqueous-rich nanodomains, which size can be tuned by changing the supporting electrolyte, and found that the reactivity of the system significantly varies with its nanostructure. Depending on the conditions, it is dominated by either the strength of short-range cation-water interactions or the formation of long chains of water molecules. This understanding paves the way toward the development of more efficient and selective electrocatalysts for the water, CO₂, O₂ or N₂ reduction.</p>

Tuning the Water Reduction Through Controlled Nanoconfinement Within an Organic Liquid Matrix

<p>The growing hydrogen-economy requires accelerating the hydrogen evolution reaction. The water dissociation step (Volmer step) has been proposed as a main kinetic limitation, but the mechanisms at play in the electrochemical double-layer are poorly understood. This is due to the ambivalent role of water: it acts both as a reactant and as a solvent. Here we propose to confine water inside an organic liquid matrix in order to isolate the sole role of water as a reactant. We observe the formation of aqueous-rich nanodomains, which size can be tuned by changing the supporting electrolyte, and found that the reactivity of the system significantly varies with its nanostructure. Depending on the conditions, it is dominated by either the strength of short-range cation-water interactions or the formation of long chains of water molecules. This understanding paves the way toward the development of more efficient and selective electrocatalysts for the water, CO₂, O₂ or N₂ reduction.</p>

Tuning the Water Reduction Through Controlled Nanoconfinement Within an Organic Liquid Matrix

<p>The growing hydrogen-economy requires accelerating the hydrogen evolution reaction. The water dissociation step (Volmer step) has been proposed as a main kinetic limitation, but the mechanisms at play in the electrochemical double-layer are poorly understood. This is due to the ambivalent role of water: it acts both as a reactant and as a solvent. Here we propose to confine water inside an organic liquid matrix in order to isolate the sole role of water as a reactant. We observe the formation of aqueous-rich nanodomains, which size can be tuned by changing the supporting electrolyte, and found that the reactivity of the system significantly varies with its nanostructure. Depending on the conditions, it is dominated by either the strength of short-range cation-water interactions or the formation of long chains of water molecules. This understanding paves the way toward the development of more efficient and selective electrocatalysts for the water, CO₂, O₂ or N₂ reduction.</p>

Tungsten-doped Ni–Co phosphides with multiple catalytic sites as efficient electrocatalysts for overall water splitting

The design of electrocatalysts including precious and nonprecious metals for the hydrogen evolution reaction (HER) in alkaline media remains challenging due to the sluggish reaction kinetics caused by the additional water dissociation step.

The activity of indenylidene derivatives in olefin metathesis catalysts

The first turnover event of an olefin metathesis reaction using a new family of homogenous Ru-based catalysts bearing modified indenylidene ligands has been investigated, using methoxyethylene as a substrate. The study is carried out by means of density functional theory (DFT). The indenylidene ligands are decorated with ortho-methyl and isopropyl groups at both ortho positions of their phenyl ring. DFT results highlight the more sterically demanding indenylidenes have to undergo a more exothermic first phosphine dissociation step. Overall, the study emphasises advantages of increased steric hindrance in promoting the phosphine release, and the relative stability of the corresponding metallacycle over classical ylidene ligands. Mayer bond orders and steric maps provide structural reasons for these effects, whereas NICS aromaticity and conceptual DFT confirm that the electronic parameters do not play a significant role.