A Magnetically Separable Fe3O4@EDTA‐gC3N4 Versatile Mesoporous Photocatalyst for CO2 Reduction and Water Splitting into Solar Fuels

In pole position: A magnetically separable Fe₃O₄@EDTA-g-C₃N₄ photocatalyst was synthesized for CO₂ reduction and water splitting. Ethylenediaminetetraacetic acid (EDTA) played a crucial role in linking Fe₃O₄ and g-CN together and in enhancing the charge transfer between them by reducing the band gap from 2.23 to 0.67 eV. This resulted in a higher methanol (375.56 μmol g⁻¹ _cat) and hydrogen (59.49 μmol hg⁻¹ _cat) yield with appreciable recyclability and stability of the photocatalyst.

Abstract

This study discusses CO₂ valorization and water splitting via photocatalysis using non-noble metal magnetically separable Fe-supported EDTA-g-C₃N₄. A mesoporous and magnetically separable Fe₃O₄@EDTA-g-C₃N₄ (F-E-g-CN ) hybrid photocatalyst was synthesized for the first time with abundant catalytic sites. Ethylenediaminetetraacetic acid (EDTA) played crucial roles in the heterostructured catalysts, such as linking Fe₃O₄ and g-CN together and enhancing charge transfer facilitating a reduced band gap from 2.23 to 0.67 eV in F-E-g-CN (1 : 1). The results indicate a promising yield of methanol (375.56 μmol g⁻¹ _cat), formic acid (18.70 μmol g⁻¹ _cat), and hydrogen (59.49 μmol hg⁻¹ _cat) under the optimized reaction conditions. The catalyst revealed an increase in photoactivity for CO₂ conversion and water splitting by factor of 12.38 and 12.05 for methanol and 100-fold higher for hydrogen production than the pure g-CN and E-g-CN, respectively. An isotopic tracer experiment was carried out using ¹³CO₂, confirming the carbon source of methanol. This research will offer additional in-depth insights into the design of photocatalytic CO₂ reduction and water-splitting reactions based on g-CN.

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