The durable and inexpensive electrocatalyst generates clean hydrogen and oxygen from water

The durable and inexpensive electrocatalyst generates clean hydrogen and oxygen from water

This article has been reviewed in accordance with Science


Natural clay magadite containing silicon (Si) was heated in a sealed vessel in an aqueous solution containing iron chloride (FeCl).3) and nickel chloride (NiCl2) to form silicates composed of nickel (Ni), iron (Fe), and Si. The metal silicates were then reduced by adding electrons to the metal silicate atoms with magnesium, salt and heat to create a more organized structure of the metal silicate (ferric and nickel silicate). The graph shows the lower voltage required for the ferric nickel silicate (FeNiSi) electrocatalyst to produce hydrogen and oxygen gas compared to NiSi and FeSi alloys. Image source: Nanoenergy Research, Tsinghua University Press

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Natural clay magadite containing silicon (Si) was heated in a sealed vessel in an aqueous solution containing iron chloride (FeCl).3) and nickel chloride (NiCl2) to form silicates composed of nickel (Ni), iron (Fe), and Si. The metal silicates were then reduced by adding electrons to the metal silicate atoms with magnesium, salt and heat to create a more organized structure of the metal silicate (ferric and nickel silicate). The graph shows the lower voltage required for the ferric nickel silicate (FeNiSi) electrocatalyst to produce hydrogen and oxygen gas compared to NiSi and FeSi alloys. Image source: Nanoenergy Research, Tsinghua University Press

A new electrocatalyst made from nickel (Ni), iron (Fe) and silicon (Si) reduces the amount of energy needed for H2 synthesis.2 of water in a simple and cost-effective way, which increases the practicality of H2 As the clean and renewable energy of the future.

Hydrogen is a highly flammable gas that can help the world achieve its clean energy goals if it is manufactured in an environmentally responsible manner. The main obstacle to producing hydrogen gas from water is the large amount of energy required to electrolyze water, or split water molecules into hydrogen gas (H).2) and oxygen (O2).

Most h2 Today it is produced from fossil fuels, which contribute to global warming. Manufacturing h2 Extracting water through a hydrogen evolution reaction (HER) requires the use of a catalyst, or agent that reduces the amount of energy required for the chemical reaction. Until recently, these catalysts consisted of rare earth metals, such as platinum, reducing the cost effectiveness and practicality of clean hydrogen production.

A group of materials scientists from Dalian University of Technology in Dalian, China has manufactured an electrocatalyst, or catalyst that uses electricity, using inexpensive materials and methods to effectively reduce the energy required to generate clean H2.2 from water. Importantly, the alloy or mixture of iron-nickel silicide (FeNiSi) also reduces the energy needed to generate O2 of water, making the catalyst bi-functional.

The researchers published their study in Nano energy research.

“What really limits the development and practical application of water electrolysis technology is electrocatalytic materials. At present, common catalysts, such as precious metals… are mostly single-functional catalysts, which limits the practical application of water electrolysis to produce hydrogen. Therefore Yifu Zhang, senior author of the study and a researcher at the College of Chemistry at Dalian University of Technology, said that the research and development of efficient, stable, cheap and environmentally friendly bifunctional electrocatalytic materials is a fundamental goal in the field of electrocatalysis.

Transition metal silicide alloys are unique compounds commonly used in energy-related fields, are produced inexpensively and show promise as potential electrocatalysts for water hydrolysis. These alloys are made of transition metals, which are excellent catalysts that freely donate and accept electrons in chemical reactions, and Si atoms, which enhance the stability, heat resistance and accessibility of the alloy’s transition metal atoms when electricity is applied.

Fe and Ni, which are transition metals, are well suited for use in water-splitting transition metal silicate clasts. “Nickel silicide has been deeply studied due to its low resistivity and high metallurgical activity, especially…in electrochemical fields. In addition, many recent studies have shown that Fe-Ni-based materials have great potential in the field of electrochemical water splitting,” Zhang said. : “The aim of this work was to develop a low-cost and environmentally friendly route to prepare nickel iron silicide as a bi-functional electro-hydrocatalyst (EWS).”

The research team synthesized FeNiSi in two steps. First, natural clay magadite, a source of silicon, iron chloride and nickel chloride, was heated under pressure to form ferric-nickel silicates. The ferric-nickel silicates were then combined and heated with magnesium and sodium chloride (table salt) to develop the desired structure of the FeNiSi alloy. More importantly, this was the first time a metal silicide alloy had been synthesized using this type of chemical reaction using metal silicates as the reaction material.

Scanning electron microscopy and X-ray characterization techniques revealed that the manufacturing process created numerous porous structures in the final FeNiSi alloy, resulting in increased surface area and overall electrocatalytic performance. The FeNiSi alloy reduces the potential required to separate oxygen and hydrogen from water by 308 mV for the oxygen evolution reaction (OER) and 386 mV for the HER reaction, respectively, at a current of 10 mA·cm-2. The electrostimulator also showed sufficient durability after 15 hours of use.

The research team is looking forward to FeNiSi and other transition metal silicates contributing to the synthesis of clean hydrogen gas to meet future energy needs.

“This work not only provides an easy way to synthesize intermetallic silicides with large porous structures, but also allows intermetallic silicicides to be considered as a dual-functional electrocatalyst for early warning system. Low-cost and efficient electrocatalysts for intermetallic silicides will provide new opportunities for… He said Zhang: “Energy conversion.”

Other contributors include Shuyang Jing, Yang Mu, Zhanming Gao, and Xuying Dong from the School of Chemistry at Dalian University of Technology in Dalian, China; Changhong Ming from the School of Chemistry and School of Environmental and Chemical Engineering at Dalian University of Technology; and Qi Huang of the School of Chemistry and Molecular Sciences, Wuhan University in Wuhan, China.

more information:
Xuyang Jing et al, Intermetallic ferric nickel silicate alloy derived from magadite by magnesium thermal reaction as a bi-functional electrocatalyst for general water splitting, Nano energy research (2023). doi: 10.26599/NRE.2023.9120104

Provided by Tsinghua University Press

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