RuO2 Nanorods as an Electrocatalyst for Proton Exchange Membrane Water Electrolysis.

Michael W. Cross,Walter J. Varhue,Richard P. Smith

doi:10.3390/mi12111412

Michael W. Cross, Walter J. Varhue + Show 1 more

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https://doi.org/10.3390/mi12111412

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Journal: Micromachines	Publication Date: Nov 17, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: Norwich University, University of Vermont

Abstract

A custom-built PEM electrolyzer cell was assembled using 6” stainless-steel ConFlat flanges which were fitted with a RuO2 nanorod-decorated, mixed metal oxide (MMO) ribbon mesh anode catalyst. The current density–voltage characteristics were measured for the RuO2 nanorod electrocatalyst while under constant water feed operation. The electrocatalytic behavior was investigated by making a series of physical modifications to the anode catalyst material. These experiments showed an improved activity due to the RuO2 nanorod electrocatalyst, resulting in a corresponding decrease in the electrochemical overpotential. These overpotentials were identified by collecting experimental data from various electrolyzer cell configurations, resulting in an improved understanding of the enhanced catalytic behavior. The micro-to-nano surface structure of the anode electrocatalyst layer is a critical factor determining the overall operation of the PEM electrolyzer. The improvement was determined to be due to the lowering of the potential barrier to electron escape in an electric field generated in the vicinity of a nanorod.

Highlights

The widespread use of renewable energy can be assisted by the development of a process to generate H2 by splitting water
The kinetics of the electrochemical reactions was was monitored by measuring the electrical current provided to the anode electrode as a function monitored by measuring the electrical current provided to the anode electrode as a funcof the applied voltage (Vop )
The disassembly of the existing multiple electrode assembly (MEA) structure resulted in additional resistances to current flow and impediments to ion diffusion

Summary

Introduction

The widespread use of renewable energy can be assisted by the development of a process to generate H2 by splitting water. The conversion of electrical energy into chemical energy through the generation of hydrogen for storage is an enabling technology for the widespread use of renewable energy. Inputs of harvested renewable energy and/or underutilized off-peak sources of electrical power can be better managed with the generation and storage of hydrogen. Electrolysis of water is the decomposition of water molecules into oxygen and hydrogen molecules powered by electricity. Efficient electrolysis has been achieved in electrochemical cells which increase performance through the use of a noble-metal electrocatalyst. Designing these electrocatalyst systems to be less material-dependent, more durable, and more efficient will support the conversion of electrical power into hydrogen as a fuel for energy storage.

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