Hydrogen gas, a clean and renewable alternative to fossil fuels, has the potential to revolutionize the energy industry. However, current industrial hydrogen production methods release carbon into the atmosphere, contributing to environmental pollution.
A recent breakthrough involves a novel catalyst called carbon compound nickel-iron-molybdenum-phosphide anchored on nickel foam (NiFeMo-P-C). This innovative catalyst has successfully reduced the amount of electricity needed to generate hydrogen and oxygen from water, offering a cleaner and more efficient method for hydrogen gas production.
A team of leading chemical engineers has developed this cost-efficient catalyst, designed to minimize the energy requirements for water electrolysis, a process that uses electricity to split water molecules into hydrogen and oxygen. This breakthrough relies on two crucial reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER).
The catalyst employs a transition metal alloy, specifically nickel-iron-molybdenum (NiFeMo), due to its electron orbital properties, making it an ideal electron donor and acceptor in chemical reactions. Additionally, phosphide has been incorporated into the catalyst to enhance corrosion resistance in an alkaline electrolyte solution.
Published in Nano Research Energy on July 7, the study’s supervisor, Jingjing Tang, an associate professor at Central South University in Changsha, China, emphasized the significance of hydrogen as an alternative to fossil fuels. She noted, “Hydrogen is recognized as the most ideal alternative to fossil fuels due to its high energy density, high heat conversion efficiency, and zero carbon emissions.”
Common industrial hydrogen production methods, such as steam reforming of natural gas and coal gasification, rely on fossil fuels and cause substantial environmental pollution. Water electrolysis, on the other hand, utilizes water as a raw material and converts electricity into chemical energy, representing a clean and promising hydrogen production technology.
Prior catalysts used for HER and OER reactions featured platinum and iridium oxide, valuable but expensive and scarce elements. The development of an affordable catalyst that reduces the activation energy of both reactions not only lowers manufacturing costs but also enhances the commercial viability of clean hydrogen gas production.
One of the catalyst’s key challenges was meeting the unique requirements of OER, which performs better in alkaline solutions due to its sluggish kinetics. To address this, the team designed the alloy and metal phosphide to ensure the catalyst’s stability in alkaline conditions.
The researchers confirmed the catalyst’s composition and valence state using X-ray photoelectron spectroscopy (XPS) measurement. The NiFeMo-P-C catalyst demonstrated remarkable performance, requiring very low overpotentials for HER (87 mV for a current density of 10 mA·cm–2) and OER (196 mV for a current density of 10 mA·cm–2). The cell voltage needed for water electrolysis using this catalyst was only 1.50 V at 10 mA·cm–2.
The team remains optimistic about the potential of their discovery to enable clean hydrogen production. Tang explained, “Unlike most bifunctional catalysts, NiFeMo-P-C can achieve excellent catalytic performance without complicated preparation steps and elaborate nanostructures. Besides, the superior durability without any voltage attenuation within 50 hours makes NiFeMo-P-C an ideal candidate for large-scale hydrogen production.”
Contributors to this research include scientists from the School of Metallurgy and Environment at Central South University in Changsha, China.
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