N-doped carbon encapsulated nickel nanoparticles: rational fabrication and ultra-high performance for ethanol oxidation

Fast catalytic transfer hydrogenation of phenol to cyclohexanol over urea modified Ni@CN nanoparticles

The Ni@CN-450 catalyst prepared via direct pyrolysis of Ni-MOF-74(N) exhibited superior catalytic activity in catalytic transfer hydrogenation.

Supporting effects of a N-doped carbon film electrode on an electrodeposited Ni@Ni(OH)2 core-shell nanocatalyst in accelerating electrocatalytic oxidation of oligosaccharides

The supporting effect of a N-doped carbon film induced superior crystallinity in electrodeposited Ni@Ni(OH)2 core-shell nanoparticles. This improvement resulted in a much higher regeneration rate of catalytic sites (NiOOH), leading to higher oxidation currents of sugars. Also, the overpotential of the maltopentaose (G5) oxidation reaction decreased significantly, probably due to the effect of the electrostatic interaction between NPs and G5.

N-doped porous carbon supported Ni catalysts derived from modified Ni-MOF-74 for highly effective and selective catalytic hydrodechlorination of 1,2-dichloroethane to ethylene

Metal-organic frameworks (MOFs) have received significant attention as promising precursors or sacrificial templates in the preparation of porous carbon supported catalysts. In this study, N-doped porous carbon supported Ni catalysts (denoted as Ni/NC) were prepared using furfuryl alcohol (FA) loaded Ni-MOF-74 as the precursor followed by NH₄OH treatment and pyrolysis under N₂ atmosphere. For comparison purpose, Ni catalysts supported on porous carbon (denoted as Ni/C) were also prepared by direct pyrolysis of Ni-MOF-74. The selective gas phase catalytic hydrodechlorination of 1,2-dichloroethane to ethylene was carried out to evaluate the catalytic performances of the catalysts. It was found that for Ni catalysts prepared at the same pyrolysis temperature, Ni particle sizes in Ni/NC catalysts were significantly smaller (20-40% smaller) than that of Ni/C. This reflected that pre-modification of Ni-MOF-74 using FA and NH₄OH could effectively increase Ni dispersion in Ni catalysts derived from Ni-MOF-74. Moreover, Ni/NC had a markedly stronger ability to form spillover H₂ owing to the enhanced metal-support interactions by N-doping. Accordingly, Ni/NC catalysts exhibited much higher catalytic activities than Ni/C catalysts. The turnover frequencies of Ni/NC catalysts were found to be 1.22-1.65 times higher than Ni/C catalysts. Increasing pyrolysis temperature led to decreased catalytic activities of both Ni/C and Ni/NC catalysts, due to the aggregation of Ni particles at higher treatment temperature. The findings from this study demonstrate that the MOF-mediated synthesis method offers a promising way to prepare Ni-based catalysts for catalytic hydrodechlorination of chlorinated hydrocarbons.

CuO/Co(OH)2 Nanosheets: A Novel Kind of Electrocatalyst for Highly Efficient Electrochemical Oxidation of Methanol

With the booming of non-noble-metal electrocatalysts for efficient oxygen reduction reaction under alkaline conditions, corresponding anodic catalysts for methanol oxidation are urgently needed especially for direct methanol fuel cells with alkaline membranes. Here, we report the facile synthesis of a CuO/Co(OH)₂-nanosheet composite as a novel kind of high-performance electrochemical methanol oxidation reaction (MOR) catalyst. The obtained material with an optimized Cu/Co ratio shows much enhanced mass activity and area-specific activity, as well as excellent stability. The electronic structure interaction between Cu and Co, which results in the Co ion binding-energy elevation, is considered to be the origin of high MOR performance. This work promises the great potential of cobalt hydroxide as a novel kind of MOR catalyst and may arouse much interest in exploring more hydroxides as efficient nonprecious-metal electrocatalysts for MOR.

Stable and Efficient Nitrogen-Containing Carbon-Based Electrocatalysts for Reactions in Energy-Conversion Systems

High activity and stability are crucial for the practical use of electrocatalysts in fuel cells, metal-air batteries, and water electrolysis, including the oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, and oxidation reactions of formic acid and alcohols. Electrocatalysts based on nitrogen-containing carbon (N-C) materials show promise in catalyzing these reactions; however, there is no systematic review of strategies for the engineering of active and stable N-C-based electrocatalysts. Herein, a comprehensive comparison of recently reported N-C-based electrocatalysts regarding both electrocatalytic activity and long-term stability is presented. In the first part of this review, the relationships between the electrocatalytic reactions and selection of the element to modify the N-C-based materials are discussed. Afterwards, synthesis methods for N-C-based electrocatalysts are summarized, and strategies for the synthesis of highly stable N-C-based electrocatalysts are presented. Multiple tables containing data on crucial parameters for both electrocatalytic activity and stability are displayed in this review. Finally, constructing M-N_x moieties is proposed as the most promising engineering strategy for stable N-C-based electrocatalysts.

Graphene-supported platinum/nickel phosphide electrocatalyst with improved activity and stability for methanol oxidation

In this paper, we report a novel catalyst using Ni₂P as a cocatalyst of Pt supported on graphene for methanol oxidation.