Iron compounds from Euterpe oleracea Mart (açai) seed ash as electrocatalyst for oxygen evolution reaction

IF 5.45 Q1 Physics and Astronomy

Nano-Structures & Nano-Objects Pub Date : 2025-09-27 DOI:10.1016/j.nanoso.2025.101558

Marcondes L. da S. Azevedo , Evanimek B.S. da Silva , Jakeline R.D. dos Santos , Kelly C. Gomes , Júlio C. de O. Freitas , Carlos A. Martínez-Huitle , Marco A. Morales

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引用次数: 0

Abstract

The production of pulp from Euterpe oleracea Mart. palm fruits (açaí) generates a significant amount of primary solid waste, whose inadequate disposal poses environmental risks. The açaí seeds ash contains iron compounds and was used as an electrocatalyst in the oxygen evolution reaction (OER) process. The ashes were obtained by calcination of açaí seeds. The samples were characterized by several techniques, including XRF, XRD, TEM, FTIR, Mössbauer and magnetometry. The Mössbauer results revealed the presence of metal iron (α-Fe) and magnetite (Fe₃O₄). The electrochemical evaluation demonstrated that açaí seeds ash had promising catalytic activity for OER, exhibiting an overpotential of 349 mV at 10 mA cm⁻². The analysis of the Tafel curve indicated a superior electron transfer kinetics of 61 mV dec⁻¹, and the chronopotentiometry tests for 16 h showed electrochemical stability. The catalytic performance was attributed to the biochar composition, rich in iron in several oxidation states, which facilitates the charge transfer. These results suggested that açaí seed ash can be a valuable source for the development of efficient electrocatalysts for OER, contributing to the production of hydrogen and the circular economy.

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马蹄莲籽灰中铁化合物作为析氧反应的电催化剂

马齿苋纸浆的生产。棕榈果（açaí）产生大量的初级固体废物，其处置不当造成环境风险。açaí种子灰分含有铁化合物，并被用作析氧反应（OER）过程中的电催化剂。灰烬是通过煅烧açaí种子获得的。采用XRF、XRD、TEM、FTIR、Mössbauer和磁强计等技术对样品进行了表征。Mössbauer结果显示，样品中存在金属铁（α-Fe）和磁铁矿（Fe3O4）。电化学评价表明açaí种子灰分对OER具有良好的催化活性，在10 mA cm−2下表现出349 mV的过电位。Tafel曲线分析表明，该材料具有61 mV dec−1的优异电子传递动力学，16 h的时间电位测试表明其具有电化学稳定性。生物炭在多种氧化态下富含铁元素，有利于电荷转移。这些结果表明，açaí种子灰可以成为开发高效OER电催化剂的宝贵资源，有助于氢气的生产和循环经济。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nano-Structures & Nano-Objects Physics and Astronomy-Condensed Matter Physics

CiteScore

9.20

自引率

0.00%

发文量

审稿时长

22 days

期刊介绍： Nano-Structures & Nano-Objects is a new journal devoted to all aspects of the synthesis and the properties of this new flourishing domain. The journal is devoted to novel architectures at the nano-level with an emphasis on new synthesis and characterization methods. The journal is focused on the objects rather than on their applications. However, the research for new applications of original nano-structures & nano-objects in various fields such as nano-electronics, energy conversion, catalysis, drug delivery and nano-medicine is also welcome. The scope of Nano-Structures & Nano-Objects involves: -Metal and alloy nanoparticles with complex nanostructures such as shape control, core-shell and dumbells -Oxide nanoparticles and nanostructures, with complex oxide/metal, oxide/surface and oxide /organic interfaces -Inorganic semi-conducting nanoparticles (quantum dots) with an emphasis on new phases, structures, shapes and complexity -Nanostructures involving molecular inorganic species such as nanoparticles of coordination compounds, molecular magnets, spin transition nanoparticles etc. or organic nano-objects, in particular for molecular electronics -Nanostructured materials such as nano-MOFs and nano-zeolites -Hetero-junctions between molecules and nano-objects, between different nano-objects & nanostructures or between nano-objects & nanostructures and surfaces -Methods of characterization specific of the nano size or adapted for the nano size such as X-ray and neutron scattering, light scattering, NMR, Raman, Plasmonics, near field microscopies, various TEM and SEM techniques, magnetic studies, etc .