Electrocatalysis is a potential method for sustainable hydrogen production, and the development of non-noble metal-based effective electrocatalysts for electrochemical water splitting is the core of exploiting and utilizing renewable energy. Herein, a stupendous electrocatalyst with multiheterostructure interfaces and 3D porous structure is synthesized, and the mechanisms of enhanced electrocatalytic activity combining multicharacterizations and density functional calculations are clarified. Especially, the fabricated Co 2 P/N@Ti 3 C 2 T x @NF (denoted as CPN@TC) exhibits an ultralow overpotential of 15 mV to arrive at a current density of 10 mA cm −2 with the long-term durability and a small Tafel slope of 30 mV dec −1 in 1 m KOH, which even compares with noble metal catalysts favorably. The outstanding HER activity is ascribed to multiheterointerfaces for adsorbing H 2 O and H*, fine conductivity for the electronic transmission, and well-designed structure for rapid transport of ions and gases. It is reasonable to think that the synthetic strategy of CPN@TC can be extended to the preparation of transition-metal-based phosphides for enhanced catalytic performance.
Preparation of high-activity and earth-abundant bifunctional catalysts for efficient electrochemical water splitting are crucial and challenging. Herein, Co-doped Ni 3 N nanosheets loaded on nickel foam (Co−Ni 3 N) were synthesized. The as-prepared Co−Ni 3 N exhibits excellent catalytic activity toward both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in alkaline media. Density functional theory (DFT) calculation reveals that Co−Ni 3 N with redistribution of electrons not only can facilitate the HER kinetics but also can regulate intermediates adsorption energies for OER. Specifically, the Co−Ni 3 N exhibits high efficiency and stable catalytic activity, with an overpotential of only 30 and 270 mV at a current density of 10 mA cm −2 for the HER and OER in 1 M KOH, respectively. This work provides strong evidence to the merit of Co doping to improve the innate electrochemical performance in bifunctional catalysts, which might have a common impact in many similar metal− metal nitride electrocatalysts.
In this study, effectively conductive rGO (reduced graphene oxide) was used as the supporter both to promote charge transfer and to refine particle size of WC, to realize efficient and stable HER performance.
It
still is a challenge to create a superior and easily coupled
bifunctional electrocatalyst for water splitting impelled by a low
voltage. In this work, the controlled growth of Co2P NAs
on the surface of a MXene (Ti3C2T
x
)-modified self-supporting electrode is demonstrated
as a competent and reliable bifunctional electrocatalyst for efficient
water splitting. The heterointerface in Co2P@Ti3C2T
x
with an optimized adsorption
free energy of H*, H2O, and better conductivity can give
enhanced HER (hydrogen evolution reaction) activity, with a low overpotential
(42 mV) at 10 mA cm–2. Additionally, the OER (oxygen
evolution reaction) activity has also been similarly strengthened
by the synergy of Co2P and MXene with an overpotential
of 267 mV to arrive at 10 mA cm–2. Furthermore,
the excellent bifunctional electrode (Co2P@Ti3C2T
x
∥Co2P@Ti3C2T
x
) exhibits
efficient engineering water-splitting performance (1.46 V@10 mA cm–2) in alkaline solution. This simple design can propose
a promising approach to exploit precious-metal-free catalysts for
energy conversion.
Abstract:The heterogeneous structure of Al alloys renders them susceptible to localized corrosion due to the different electrochemical properties existing in the Al-rich solid solution matrix and secondary phase particles. The galvanic interactions between these two phases can result in pit formation either through dissolution of the particles or corrosion of the matrix adjacent to the particles. This detrimentally localized corrosion behavior is closely related to the corrosion properties of the particles and the Al-rich matrix. The comprehensive characterization of this behavior under various and varying conditions is critical to understanding the mechanism of pit formation, selecting appropriate inhibitors, and developing protection strategies. The corrosion properties (corrosion potential, pitting potential and corrosion rate) of both secondary phase particles and Al-solid solutions in Al alloys are summarized in this review, aiming to provide a database for corrosion research applicable to the localized corrosion of Al alloys.
Developing highly efficient non-precious electrocatalytic materials for H 2 production in an alkaline medium is attractive on the front of green energy production. Herein, we successfully designed an electrocatalyst with superb hydrophilicity, high conductivity, and a kinetically beneficial structure using Ni 2 P/MXene over a 3D Ni foam (NF) for the alkaline hydrogen evolution reaction (HER) based on the laboratory and computational research works. The designed self-supported and highly effective electrocatalyst achieves a huge boost in the HER activity compared with that of pristine Ni 2 P nanosheets owing to the distinctive structure and synergy of coupling Ti 3 C 2 T x and Ni 2 P. More specifically, Ni 2 P/Ti 3 C 2 T x /NF produces an electric current density of 10 mA•cm −2 under a low overpotential (135 mV) and shows excellent durability under alkaline (1 M KOH) conditions, and the observed performance degradation is negligible. The outstanding HER activity makes the synthetic strategy of Ni 2 P/Ti 3 C 2 T x /NF a potential approach to be extended to other transition-metal-based electrocatalysts for enhanced catalytic performance.
In this work, a label-free and sensitive electrogenerated chemiluminescence (ECL) aptasensing scheme for K(+) was developed based on G-rich DNA aptamer and chitosan/Ru(bpy)3(2+)/silica (CRuS) nanoparticles (NPs)-modified glass carbon electrode. This ECL aptasensing approach has benefited from the observation that the G-rich DNA aptamer at the unfolded state showed more ECL enhancing signal at CRuS NPs-modified electrode than the binding state with K(+), which folds into G-quadruplex structure. As such, the decreasing ECL signals could be used to detect K(+). Compared to other aptasensing K(+) approaches previously reported, the proposed ECL sensing scheme is a label-free aptasensing strategy, which eliminates the labeling, separation, and immobilization steps, and behaves in a simple, low-cost way. More importantly, because the proposed ECL sensing mechanism utilizes the nanosized ECL active CRuS NPs to sense the nanoscale conformation change from the aptamer binding to target, it is specific. In addition, due to the great conformation changes of the aptamer's G-bases on CRuS NPs and the excellent ECL enhancing effect of guanine bases to the Ru(bpy)3(2+) ECL reaction, a 0.3 nM detection limit for K(+) was achieved with the proposed ECL method. On the basis of these advantages, the proposed ECL aptasensing method was also successfully used to detect K(+) in colorectal cancer cells.
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