Promoting Active Sites in Core–Shell Nanowire Array as Mott–Schottky Electrocatalysts for Efficient and Stable Overall Water Splitting

Abstract

Developing earth-abundant, active, and robust electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a vital challenge for efficient conversion of sustainable energy sources. Herein, metal-semiconductor hybrids are reported with metallic nanoalloys on various defective oxide nanowire arrays (Cu/CuO x , Co/CoO x , and CuCo/ CuCoO x ) as typical Mott-Schottky electrocatalysts. To build the highway of continuous electron transport between metals and semiconductors, nitrogendoped carbon (NC) has been implanted on metal-semiconductor nanowire array as core-shell conductive architecture. As expected, NC/CuCo/CuCoO x nanowires arrays, as integrated Mott-Schottky electrocatalysts, present an overpotential of 112 mV at 10 mA cm −2 and a low Tafel slope of 55 mV dec −1 for HER, simultaneously delivering an overpotential of 190 mV at 10 mA cm −2 for OER. Most importantly, NC/CuCo/CuCoO x architectures, as both the anode and the cathode for overall water splitting, exhibit a current density of 10 mA cm −2 at a cell voltage of 1.53 V with excellent stability due to high conductivity, large active surface area, abundant active sites, and the continuous electron transport from prominent synergetic effect among metal, semiconductor, and nitrogen-doped carbon. This work represents an avenue to design and develop efficient and stable Mott-Schottky bifunctional electrocatalysts for promising energy conversion.

Ru@RuO2 Core‐Shell Nanorods: A Highly Active and Stable Bifunctional Catalyst for Oxygen Evolution and Hydrogen Evolution Reactions

“…Apparently, the catalytic stability of Ru-150 for OER has relatively improved in The catalytic activity of Ru@RuO 2 core-shell nanorods is compared with the state-of-art OER catalysts. Figure 5a shows polarization 15.6 times higher of 40% Pt/C, and 6.5 times higher of IrO 2 . Furthermore, the overpotential at the current density of 10 mA cm À2 of Ru@RuO 2 -200 (320 mV) is 210 mV smaller than that of the state-of-art OER catalyst IrO 2 (530 mV), as shown in Figure 5c.…”

“…Water electrolysis to generate hydrogen has received much attention recently . Electrochemical water splitting undergoes an oxygen evolution reaction (OER) at the anode and a hydrogen evolution reaction (HER) at the cathode . Highly active catalysts are regularly demanded to lower the overpotentials and accelerate the reaction rates at the electrode/electrolyte interface .…”

In‐situ One‐Step Preparation of Nickel‐Tipped N‐doped Carbon Nanotubes for Oxygen Reduction

“…Note that the atomic percentage of N dopant reached 10.37 %. [15] Additionally, Raman spectra (Figure 2d) show the graphene-like D band (1350 cm À 1 ) and G band (1580 cm À 1 ) of the N-CNTs/E-NNPs, indicating enhanced electron transfer. [5d] Graphitic N can improve electronic conductivity of carbon layer, and pyrrole N and pyridine N can enhance the electrocatalysts activity.…”

Modulierung der elektronischen Strukturen anorganischer Nanomaterialien für eine effiziente elektrokatalytische Wasserspaltung

“…[162][163][164][165] Allerdings kçnnen nur wenige Heterostrukturen ¾nderungen der elektronischen Struktur herbeiführen und so die katalytische Effizienz durch Herabsetzung des Kontaktwiderstands steigern. Dieser Kontakt zwischen Halbleiter-u nd Lei-termaterialien wird als Mott-Schottky-Kontakt bezeichnet und kann zur Energiebandverzerrung der Grenzschicht sowie Ladungswanderung zwischen zwei Materialien führen.…”

“…[159,168,169] Statt der Herstellung gestapelter und verdichteter Heterostrukturen synthetisierten Fu et al beispielsweise eine 2D-In-Plane-WC/ Graphen-Heterostruktur.D iese bewirkte einen effizienteren Elektronentransfer zwischen Graphen und WC. [162] Copyright 2018, Wiley-VCH. Dieser synergetische Effekt verringerte die Tafel-Steigung auf 51 mV dec À1 ,ein Wert, der besser ist als bei den meisten Nichtedelmetall-Elektrokatalysatoren.…”