Air‐Assisted Transient Synthesis of Metastable Nickel Oxide Boosting Alkaline Fuel Oxidation Reaction

Abstract

Low molecular weight alcohols, such as ethanol, are clean, economical and sustainable energy sources which can be easily obtained, stored, and transported. [1] At present, the platinum-based noble metal catalysts are considered as highly efficient electrocatalysts for alkaline alcohols oxidation reactions. [4-6] Nevertheless, vulnerable CO poisoning effect, sluggish kinetics of anodic oxidation as well as high price of noble metal catalysts seriously hampered their development. Therefore, the research interests in developing high efficiency and low cost anodic electrocatalysts are activated to facilitate the largescale commercialization of fuel cell in the future. Non-noble metal materials which have made great progress to date are regarded as suitable and promising alternative electrocatalysts for alcohols electrooxidation. [7-9] Among them, nickel-based materials have been introduced as a kind of active electrocatalysts in the oxidation of methanol and other alcohols. [10-13] Despite considerable progress, the high onset potential and the inferior catalytic activity for alcohols electrooxidation severely hinder the further applications of nickelbased materials. In this case, it is necessary to design catalysts Construction of active and durable non-noble-metals based electrocatalysts is one of important requirements for the practical application and development of fuel cells, which are presently inhibited by relative sluggish charge transport and reaction kinetics. Herein, highly dispersed ultrathin carbon-coated nickel oxide nanoparticles settled on carbon cloth (NiO@C/CC) as efficient catalysts for alkaline fuels oxidation are synthesized via an air-assisted transient thermal shock strategy. This NiO@C/CC catalyst induces an outstanding catalytic activity (up to 119.1 mA cm −2) and durability (a little current decay during tests) in electrooxidation for ethanol, even for methanol and ethylene glycol, which outperforms most of the reported non-noble metal catalysts. The excellent catalytic performance of NiO@C/CC is essentially attributed to the oxygen vacancies, high concentration, high-valence-state Ni, and carbon layers of NiO@C NPs, which contribute to regulate the surface properties and electronic structure, enhance charge transfer, and provide abundant active sites, promoting adsorption capacity of reactant molecules on its surface. The facile and promising air-assisted transient thermal shock strategy can be extended to guide rational design and rapid synthesis of transition metal compounds as advanced catalysts for alkaline direct alcohol fuel cells.

Modulating Electronic Structure of an Au‐Nanorod‐Core–PdPt‐Alloy‐Shell Catalyst for Efficient Alcohol Electro‐Oxidation

“…Direct alcohol fuel cells (DAFCs) utilize alcohol oxidation reactions (AORs) to generate electricity. [1][2][3][4][5][6] Compared with hydrogen in proton-exchange membrane fuel cells, DAFCs effectively controlled, up to the difference of intrinsic lattice parameters between the core and the shell. [34][35][36][37][38][39][40][41] For example, an expanded strain increases the d-band center of the active shell, resulting in strengthened adsorption of ethanol and OH species, and eventually much facilitated ethanol electrooxidation.…”

“…[7][8][9][10][11] In this regard, various catalysts of both noble and non-noble metals have been designed and synthesized to boost such sluggish AORs. Although noble metal catalysts (e.g., Pd, Pt, and Rh) are more expensive than non-noble metals (e.g., Ni, Co, and Mn), their more negative AOR onset potentials make them superior for the construction of DAFCs, [4,5,11] originating from their unique electronic structures. Among reported noble-based catalysts, those based on the Pt metal are regarded as the star electrocatalysts for the AORs in terms of their oxidation overpotentials and Tafel slopes.…”

Sequential self-reconstruction of localized Mo species in hierarchical carbon/Co–Mo oxide heterostructures for boosting alkaline hydrogen evolution kinetics and durability

“…S19b,† there are three typical XPS peaks of O 1s, which are attributed to the lattice oxygen, defect sites of oxygen, and absorbed water molecules on the surface, respectively. 33 The larger peak area of defect sites of oxygen in Co@NCNT/CoMo y O x than that in the precatalyst indicates the presence of much more oxygen vacancies owing to the MoO 4 2− dissolution. Moreover, the N 1s spectrum of Co@NCNT/CoMoO x exhibits three peaks assigned to pyridinic N, pyrrolic N, and oxidized N, while the C 1s spectrum shows the peaks ascribed to CC/C–C, C–N, C–O, and O–CO (Fig.…”

Controllable synthesis of self-templated hierarchical Ni3S2@N-doped carbon for enhanced oxygen evolution reaction

“…shows great electroactivity with lower overpotential and higher current density, which may due to the synergistic effect of the internal highly active nanoparticles with exposed (110) plane of Ni 3 S 2 and the outer N-doped carbon in the sample, resulting in enhanced active sites on catalyst surface. [39] With the increasing of reaction time, nanosheets accumulate to micron-sized polyhedrons. In detail, Ni 2+ precursor coordinated with TU leads to multilayer stacked nanosheets on NF at first 2 h (Figure S8a) due to the abundant dangling bond on the surface of 2D interlayer.…”