Carbon-coated nickel enables fuel cell free of precious metals —

A nitrogen doped carbon-coated nickel anode can catalyze an important response in hydrogen gas cells at a fraction of the price of the dear metals presently used, Cornell College researchers have discovered.

The brand new discovery might speed up the widespread use of hydrogen gas cells, which maintain nice promise as environment friendly, clear vitality sources for autos and different purposes.

It is one among a string of discoveries for the Héctor D. Abruña lab of their ongoing seek for energetic, cheap, sturdy catalysts to be used in alkaline gas cells.

“This discovering makes progress towards utilizing environment friendly, clear hydrogen gas cells instead of fossil fuels,” stated Abruña, professor within the division of chemistry and chemical biology at Cornell College.

The outcomes revealed March 21 in “A Fully Valuable-Steel-Free Alkaline Gas Cell With Enhanced Efficiency Utilizing a Carbon-Coated Nickel Anode,” within the Proceedings of the Nationwide Academy of Sciences.

Costly valuable metals, equivalent to platinum, are presently required in hydrogen gas cells to effectively catalyze the reactions they make use of to provide electrical energy. Though alkaline polymer electrolyte membrane gas cells (APEMFCs) allow the use nonprecious steel electrocatalysts, they lack the mandatory efficiency and sturdiness to switch valuable metal-based programs.

A gas cell produces electrical energy via the hydrogen oxidation response (HOR) and an oxygen discount response (OOR). Platinum, specifically, is a mannequin catalyst for each reactions as a result of it catalyzes them effectively, and is sturdy within the acidic surroundings of a PEM gas cell, Abruña stated.

However what about different supplies?

Current experiments with nonprecious-metal HOR electrocatalysts wanted to beat two main challenges, the researchers wrote: low intrinsic exercise from too sturdy a hydrogen binding vitality, and poor sturdiness on account of speedy passivation from steel oxide formation.

To beat these challenges, the researchers designed a nickel-based electrocatalyst with a 2 nanometer shell made from nitrogen-doped carbon.

Their hydrogen gas cell has an anode (the place hydrogen is oxidized) catalyst consisting of a stable nickel core surrounded by the carbon shell. When paired with a cobalt-manganese cathode (the place oxygen is lowered), the ensuing utterly precious-metal-free hydrogen gas cell outputs greater than 200 milliwatts per sq. centimeter.

The presence of nickel oxide species on the floor of the nickel electrode slows the hydrogen oxidation response dramatically, Abruña stated. The nitrogen-doped carbon coating serves as a safety layer and enhances the HOR kinetics, making the response faster and rather more environment friendly.

As well as, the presence of the graphene coating on the nickel electrode prevents the formation of nickel oxides — leading to electrodes with dramatically enhanced lifetimes. These electrodes are additionally rather more tolerant to carbon monoxide, which quickly poisons platinum.

“Using this novel anode would dramatically decrease costs enabling the appliance of alkaline gas cells in all kinds of areas,” Abruña stated.

In February, Abruña and colleagues discovered {that a} cobalt nitride catalyst is almost as environment friendly as platinum in catalyzing the oxygen discount response.

Funding for this analysis was offered by the Heart for Alkaline-Primarily based Vitality Options, an Vitality Frontier Analysis Heart funded by the U.S. Division of Vitality, Workplace of Science, Fundamental Vitality Sciences, and the Zhuang analysis group at Wuhan College, China, supported by the Nationwide Pure Science Basis of China.

Story Supply:

Supplies offered by Cornell College. Authentic written by Kate Blackwood, courtesy of the Cornell Chronicle. Notice: Content material could also be edited for model and size.