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

Abstract

AbstractThis 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−1cat), formic acid (18.70 μmol g−1cat), and hydrogen (59.49 μmol hg−1cat) 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.