Electrocatalysis on non-metallic surfaces

Franklin, A.D.

doi:10.6028/nbs.sp.455

Cited by 18 publications

(8 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We do not believe however that our discrete oxide films are in fact any different to those reported earlier by people such as Trasatti 5 and Srinivasan. 13 It is most probable that this observation is just due to higher resolution imaging being performed in the present work. The size of these surface nanoparticles for the discrete oxides were found to be on the order of 10 nm in diameter and are uniformly coated on the oxide surface.…”

Section: Resultsmentioning

confidence: 79%

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

Godwin

Doyle

Lyons

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

RuO 2 /NiO mixed oxide electrodes prepared by thermal decomposition were examined as potential water oxidation catalysts. Addition of just 10 mol% RuO 2 to a NiO electrode was found to decrease the oxygen evolution reaction (OER) onset potential by 20% with increasing additions having significantly diminishing returns. The OER current densities for the RuO 2 /NiO electrode were found to increase when preconditioned by application of prolonged polarization regimes with the Tafel slope also decreasing when conditioned. NiO prepared by thermal decomposition was found to behave in a similar manner to other nickel oxides prepared using different methodologies and we propose a similar OER mechanism based on the kinetic data obtained using the surfaquo group concept. A dual barrier model was used to rationalize the fractional reaction order of ca. 0.5 observed for RuO 2 .Alkaline water electrolysis has become an area of intense international research due to the need for a method to efficiently produce large amounts of molecular hydrogen which would be required for a potential hydrogen economy. Currently one of the main drawbacks limiting the widespread use of this technology is in the large anodic overpotential associated with the oxygen evolution reaction (OER). Dimensionally Stable Anodes (DSA) are one such technology which can effectively catalyze the OER thus increasing the overall efficiency of the water electrolysis reaction. DSA electrodes consist of an underlying electrochemically inert valve metal substrate such as titanium or tantalum, coated usually with an oxide or mixed oxides of platinum group metals (PGM). To date, they have been employed in many industrial processes such as the chlorine evolution reaction, 1 electrowinning of metal ores 2 and as an anode for use in industrial water electrolyzers. 3 Herein, we focus attention on the latter use in an alkaline environment. DSA electrodes based on IrO 2 /RuO 2 currently exhibit one of the lowest overpotential for the oxygen evolution reaction (OER), which is said to be the 'bottleneck' or rate determining step in a water electrolyzer cell at standard operating currents. PGM oxide mixtures such as IrO 2 /RuO 2 as studied by Lyons, 3,4 Trasatti 4-6 and others on Ti exhibit extremely low OER overpotentials (ca. 0.20-0.25 V) and display long term stability in strong alkaline conditions required for an alkaline water electrolyzer setup. However, the main drawback in fully utilizing PGM oxide based DSA electrodes is in the high cost associated with these metals, and thus, significant international research is being currently focused on finding cheaper alternatives which still display relatively low overpotentials. This paper focuses on minimizing the amount of expensive PGM oxides, RuO 2 in this case which currently costs $2.1 million/ton, required by combining them with low cost NiO, currently $14 000/ton, which displays relatively low overpotentials for the OER 7-9 but at a significantly lower cost. A range of RuO 2 /NiO compositions was studied herein and the e...

show abstract

Section: Resultsmentioning

confidence: 79%

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

Godwin

Doyle

Lyons

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…As a result, the surface can be modulated to be high-conductive ("on") or insulating ("off"), strongly correlating the electrocatalytic reactions. The self-gating phenomenon can explain why ultrathin semiconductors can be used as highly efficient electrocatalysts, although semiconductors have been predicted as non-ideal catalysts due to their low intrinsic carrier concentration 23 . Importantly, our experiments suggest that the self-gating phenomena could universally exist in various semiconductors, including two-dimensional (2D) transition metal dichalcogenides (TMDs) and one-dimensional (1D) Si nanowires.…”

Section: Textmentioning

confidence: 99%

Self-gating in semiconductor electrocatalysis

et al. 2019

View full text Add to dashboard Cite

The semiconductor-electrolyte interface dominates the behaviors of semiconductor electrocatalysis, which has been modeled as a Schottky-analog junction according to the classic electron transfer theories. However, this model cannot be used to explain the extremely high carrier accumulations in ultrathin semiconductor catalysis observed in our work. Inspired by the recently developed ion-controlled electronics, we revisited the semiconductor-electrolyte interface and unraveled a universal self-gating phenomenon through micro-cell based in-situ electronic/electrochemical measurements to clarify the electronic-conduction modulation of semiconductors during electrocatalytic reaction. Then we demonstrate that the type of semiconductor catalysts strongly correlates their electrocatalysis, i.e., n-type semiconductor catalysts favor cathodic reactions such as hydrogen evolution reaction (HER), p-type ones prefer anodic reactions such as oxygen evolution reaction (OER), and bipolar ones tend to perform both anodic and cathodic reactions.Our study provides a new insight into the electronic origin of semiconductor-electrolyte interface during electrocatalysis, paving the way for designing high-performance semiconductor catalysts.

show abstract

“…Since the mid-1970s, a group of materials called transition metal chalcogenides (sulfides, selenides, and tellurides) has started to receive interest as an electrocatalyst. − Specifically, in 1974, Baresel et al , for the first time, studied various transition metal (Ti, Co, Ni, Mo, Ta, W) sulfides, selenides, and tellurides for the oxygen reduction reaction (ORR) in acidic media (4 N H 2 SO 4 ) . Ten years later, nickel sulfide was reported as the first electrocatalyst for the HER in alkaline media (1 N NaOH) by Vandenborre et al , which was the trigger for studying transition metal chalcogenides for the HER. − After Gao et al reported a Mn 3 O 4 /CoSe 2 nanocomposite as an alkaline OER electrocatalyst in 2012, researchers began exploring many types of transition metal chalcogenides for the electrocatalytic OER process, which brought the rapid growth of the chalcogenide OER electrocatalyst field.…”

Section: Transition Metal Chalcogenidesmentioning

confidence: 99%

A Review of Transition Metal Boride, Carbide, Pnictide, and Chalcogenide Water Oxidation Electrocatalysts

Kawashima,

Márquez,

Smith

et al. 2023

Chem. Rev.

View full text Add to dashboard Cite

Transition metal borides, carbides, pnictides, and chalcogenides (X-ides) have emerged as a class of materials for the oxygen evolution reaction (OER). Because of their high earth abundance, electrical conductivity, and OER performance, these electrocatalysts have the potential to enable the practical application of green energy conversion and storage. Under OER potentials, X-ide electrocatalysts demonstrate various degrees of oxidation resistance due to their differences in chemical composition, crystal structure, and morphology. Depending on their resistance to oxidation, these catalysts will fall into one of three post-OER electrocatalyst categories: fully oxidized oxide/(oxy)hydroxide material, partially oxidized core@shell structure, and unoxidized material. In the past ten years (from 2013 to 2022), over 890 peer-reviewed research papers have focused on X-ide OER electrocatalysts. Previous review papers have provided limited conclusions and have omitted the significance of “catalytically active sites/species/phases” in X-ide OER electrocatalysts. In this review, a comprehensive summary of (i) experimental parameters (e.g., substrates, electrocatalyst loading amounts, geometric overpotentials, Tafel slopes, etc.) and (ii) electrochemical stability tests and post-analyses in X-ide OER electrocatalyst publications from 2013 to 2022 is provided. Both mono and polyanion X-ides are discussed and classified with respect to their material transformation during the OER. Special analytical techniques employed to study X-ide reconstruction are also evaluated. Additionally, future challenges and questions yet to be answered are provided in each section. This review aims to provide researchers with a toolkit to approach X-ide OER electrocatalyst research and to showcase necessary avenues for future investigation.

show abstract

Electrocatalysis on non-metallic surfaces

Cited by 18 publications

References 9 publications

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

The Mechanism of Oxygen Reactions at Porous Oxide Electrodes

Self-gating in semiconductor electrocatalysis

A Review of Transition Metal Boride, Carbide, Pnictide, and Chalcogenide Water Oxidation Electrocatalysts

Contact Info

Product

Resources

About