Nanoscale nickel oxide/nickel heterostructures for active hydrogen evolution electrocatalysis

Abstract

Active, stable and cost-effective electrocatalysts are a key to water splitting for hydrogen production through electrolysis or photoelectrochemistry. Here we report nanoscale nickel oxide/nickel heterostructures formed on carbon nanotube sidewalls as highly effective electrocatalysts for hydrogen evolution reaction with activity similar to platinum. Partially reduced nickel interfaced with nickel oxide results from thermal decomposition of nickel hydroxide precursors bonded to carbon nanotube sidewalls. The metal ion-carbon nanotube interactions impede complete reduction and Ostwald ripening of nickel species into the less hydrogen evolution reaction active pure nickel phase. A water electrolyzer that achieves B20 mA cm À 2 at a voltage of 1.5 V, and which may be operated by a single-cell alkaline battery, is fabricated using cheap, non-precious metal-based electrocatalysts.

Electrocatalysts for Hydrogen Evolution in Alkaline Electrolytes: Mechanisms, Challenges, and Prospective Solutions

“…Besides, excellent dispersion makes full use of exposed active sites on catalysts to participate in electrode reaction and then improve the electrocatalytic efficiency 24. Carbon materials, such as carbon nanotubes (CNTs), graphene, graphene oxide (GO), and porous carbon materials extracted from artificial and natural carbon complexes not only increase the dispersity of the active components but also improve the conductivity of the hybrid catalysts due to their huge surface area, tunable molecular structures and superior electrical conductivity 51, 87, 88, 89. Typically, Co‐CNTs was designed as a highly active and stable electrocatalyst which is composed of Co embedded in nitrogen‐rich carbon nanotubes 90.…”

“…So far, high‐surface‐area Raney‐type designing of Ni‐based alloys as well as synthesis of heterostructured Ni‐based compounds with unique composition to modify the surface chemistry have attracted more attentions 88, 122, 123, 124. The properties of Ni surface can be modified by additional elements to improve its activity.…”

Nickel Hydr(oxy)oxide Nanoparticles on Metallic MoS2 Nanosheets: A Synergistic Electrocatalyst for Hydrogen Evolution Reaction

“…In this regard, most efforts have been devoted to developing low‐cost and earth‐abundant alternatives for large‐scale hydrogen production in past decades 11, 12, 13. A variety of earth‐abundant materials including transition metal chalcogenides,14, 15, 16, 17, 18 phosphides,19, 20, 21, 22 carbides,23, 24 metal oxides,25 and metals or their alloys26, 27, 28, 29 have been identified as potential candidates. However, a large part of these electrocatalysts only exhibit noticeable activities and stabilities in acidic electrolytes but suffer from either low activity or instability in alkaline media 30, 31, 32.…”

Unconventional Nickel Nitride Enriched with Nitrogen Vacancies as a High‐Efficiency Electrocatalyst for Hydrogen Evolution

“…Specifically, these two distinct mechanisms involve three principal steps, referring to the Volmer (adsorption and electrochemical reduction of water: H 2 O + e → H* + OH − ), the Heyrovsky (electrochemical desorption: H* + H 2 O + e → H 2 + OH − ), and the Tafel (chemical desorption: H* + H* → H 2 ) reactions 26. Tafel plot analysis is generally utilized to elucidate the reaction mechanism, which may provide information associated with the rate‐determining steps 27.…”