Methanol and Acetic Acid from CH₄ and CO₂: The Role of Copper Speciation in Zeolite Cu‐FER

Abstract This study highlights the efficiency of Cu‐FER catalysts with varying copper loadings in transforming carbon dioxide (CO 2 ) and methane (CH 4 ) into methanol or acetic acid. The XAS, UV–vis, and FTIR analyses confirmed that Cu‐FER catalysts with low copper loading contain a high fraction of isolated Cu 2+ cations, while those with high copper loading exhibit a significant presence of Cu oxo‐species. In‐situ studies (FTIR and mass spectrometry) revealed that bare Cu(II) cations, in synergy with Brønsted acid sites, facilitate the conversion of CO 2 and CH 4 into acetic acid via coupled oxidation and carbonylation reactions. In contrast, the absence of Brønsted acid sites and the dominance of Cu oxo‐species in high‐loaded Cu‐FER favor the formation of methanol. Importantly, the findings confirm that the transformation of CO 2 and CH 4 into oxygen‐containing products occurs under in‐situ conditions, with products detected at temperatures below 300 °C. These results provide valuable insights for designing zeolite‐based catalysts optimized for the selective production of specific oxygenated compounds from CO 2 and CH 4 , offering a promising strategy for the utilization of these greenhouse gases.