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Research Article Issue
Confinement synergy at the heterointerface for enhanced oxygen evolution
Nano Research 2023, 16 (7): 8793-8799
Published: 30 March 2023
Downloads:51

Two-dimensional transition metal hydroxides with abundant reserves and low prices have played an indispensable role in energy catalytic applications. Recent reports indicated that the incorporation of Fe species into Co-based catalysts can synergistically enhance oxygen evolution reaction (OER) activity. Constructing a heterointerface on the surface of Co-based catalysts can provide a platform to investigate the role of heterointerface in reaction kinetics. Herein, we constructed a Fe-O-Co heterointerface without electronic effect by depositing FeOx clusters on the oxygen vacancies of CoOOH surface. FeOx/CoOOH exhibited excellent OER intrinsic activity, which can deliver the turnover frequency (TOF) of 4.56 s−1 at the overpotentials of 300 mV and the Tafel slope of 33 mV·dec−1. In-situ electrochemical impedance spectroscopy (EIS) and density functional theory (DFT) calculations demonstrated that the synergistic effect between Fe sites and Co sites confined at the Fe-O-Co heterointerface accelerated the charge transfer during OER and optimized the adsorption of oxygen intermediates, consequently enhancing OER.

Research Article Issue
Electrodeposited highly-oriented bismuth microparticles for efficient CO2 electroreduction into formate
Nano Research 2022, 15 (12): 10078-10083
Published: 26 April 2022
Downloads:146

Bi is one of the most fascinating catalysts for the formation of HCOO towards CO2 electroreduction. Herein, we developed electrodeposited angular-shaped Bi microparticles (Bi MP) with exposed surfaces of {003} and {101} planes as efficient catalyst for the electroreduction of CO2 into HCOO. During CO2 electroreduction, Bi MP achieved a Faraday efficiency (FE) for HCOO of higher than 95% over a wide range of applied potential from −0.6 to −1.1 V versus reversible hydrogen electrode (vs. RHE), whereas the FE for HCOO of Bi nanoflakes (Bi NF) with exposed surfaces of {104} and {110} planes was around 70%. At −1.1 V vs. RHE, the partial current density for HCOO of Bi MP was −271.7 mA·cm−2, 1.56 times as high as that of Bi NF. According to kinetic analysis and mechanistic study, highly-oriented surface of Bi MP not only facilitated Faradaic process and accelerated reaction kinetics via enhancing the CO2 activation, but also restrained competing hydrogen evolution reaction, thus boosting catalytic performance of the electroreduction of CO2 into HCOO.

Research Article Issue
Ethylenediaminetetraacetic acid-assisted synthesis of Bi2Se3 nanostructures with unique edge sites
Nano Research 2016, 9 (9): 2707-2714
Published: 05 July 2016
Downloads:19

Nanomaterials with unique edge sites have received increasing attention due to their superior performance in various applications. Herein, we employed an effective ethylenediaminetetraacetic acid (EDTA)-assisted method to synthesize a series of exotic Bi2Se3 nanostructures with distinct edge sites. It was found that the products changed from smooth nanoplates to half-plate-containing and crown-like nanoplates upon increasing the molar ratio of EDTA to Bi3+. Mechanistic studies indicated that, when a dislocation source and relatively high supersaturation exist, the step edges in the initially formed seeds can serve as supporting sites for the growth of epilayers, leading to the formation of half-plate-containing nanoplates. In contrast, when the dislocation source and a suitably low supersaturation are simultaneously present in the system, the dislocation-driven growth mode dominates the process, in which the step edges form at the later stage of the growth responsible for the formation of crown-like nanoplates.

Research Article Issue
One-pot synthesis of Bi2Se3 nanostructures with rationally tunable morphologies
Nano Research 2015, 8 (11): 3612-3620
Published: 26 September 2015
Downloads:22

Shape control has proven to be a powerful and versatile means of tailoring the properties of Bi2Se3 nanostructures for a wide variety of applications. Here, three different Bi2Se3 nanostructures, i.e., spiral-type nanoplates, smooth nanoplates, and dendritic nanostructures, were prepared by manipulating the supersaturation level in the synthetic system. This mechanism study indicated that, at low supersaturation, defects in the crystal growth could cause a step edge upon which Bi2Se3 particles were added continuously, leading to the formation of spiral-type nanoplates. At intermediate supersaturation, the aggregation of amorphous Bi2Se3 particles and subsequent recrystallization resulted in the formation of smooth nanoplates. Furthermore, at high supersaturation, polycrystalline Bi2Se3 cores formed initially, on which anisotropic growth of Bi2Se3 occurred. This work not only advances our understanding of the growth mechanism but also offers a new approach to control the morphology of Bi2Se3 nanostructures.

Research Article Issue
Concave Cu-Pd bimetallic nanocrystals: Ligand-based Co-reduction and mechanistic study
Nano Research 2015, 8 (7): 2415-2430
Published: 12 May 2015
Downloads:10

The synthesis of highly uniform alloy nanocrystals with a concave feature is desirable for applications in catalysis but is an arduous task. This article proposes an initiative protocol for the fabrication of novel Cu-Pd alloy nanocrystals, wherein the volume of decylamine (DA) in the reaction system was found to greatly influence the formation of different morphologies, including the tetrahedron (TH), concave tetrahedron (CTH), rhombohedral-tetrapod (RTP), and tetrapod (TP). The alloy structure of the products arises from the coordination interaction between the DA and metal ions, which affects the reduction potential of Cu and Pd species, and thus yields co-reduction. Other reaction parameters, such as the type of ligand, amount of reductant, and temperature, were also altered to study the growth mechanism, yielding consistent conclusions in the diffusion-controlled regime. As a catalyst, 48-nm Cu-Pd concave tetrahedral nanocrystals were highly active for the hydrogenation of 3-nitrostyrene and exhibited > 99.9% chemoselectivity to C=C instead of -NO2.

Research Article Issue
Controlling the lateral and vertical dimensions of Bi2Se3 nanoplates via seeded growth
Nano Research 2015, 8 (1): 246-256
Published: 20 December 2014
Downloads:10

Modulation of the morphology of nanostructures is often a rewarding but challenging task. We have employed the seeded growth method and induced kinetic control to synthesize Bi2Se3 nanoplates with modifiable morphology. By manipulating the rate at which precursor solutions were injected into seeds solution with syringe pumps, two distinctive growth modes could be realized. With a fast injection, the thickness of Bi2Se3 nanoplates slightly increased from ~7.5 nm (seeds) to ~9.5 nm while the edge length grew up from ~160 nm (seeds) to ~12 μm, after 6 successive rounds of seeded growth. With a slow injection, the thickness and edge length increased simultaneously to ~35 nm and ~6 μm after 6 rounds of growth, respectively. These two modes could be viewed as a competition between atomic deposition and surface migration. The products showed interesting, thickness-dependent Raman properties. In addition, NIR transparent, highly conductive and flexible Bi2Se3 thin films with different thicknesses were constructed by the assembly of the as-synthesized Bi2Se3 nanoplates. This approach based on seeded growth and kinetic control can significantly promote the development of versatile nanostructures with diverse morphology.

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