CuxOy nanoparticles and Cu–OH motif decorated ZSM-5 for selective methane oxidation to methyl oxygenates

• Published in: Journal of colloid and interface science Vol. 645; pp. 964 - 973
• Main Authors: Jin, Jingting, Li, Wenzhi, Zhang, Lulu, Zhu, Leyu, Wang, Liqun, Zhou, Zheng
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.09.2023
• Subjects: Copper Hydroxyl; Cu-ZSM-5; CuxOy Nanoparticles; Methane Oxidation; Methanol; Synergistic effect; Tunable active sites; Tunable active sites; Methane Oxidation; CuxOy Nanoparticles; Copper Hydroxyl; Synergistic effect; Cu-ZSM-5; Methanol
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.04.170

Tunable active sites emerged over Cu-ZSM-5 catalysts via modulating Cu contents showed excellent catalytic performance in methane to methanol conversion. The generation of CH3OH was operated under the synergetic effect of the CuxOy NPs and Cu–OH motif, in which multiple mechanisms via methyl intermediates and free radicals (•OH/•OOH) in the liquid phase. [Display omitted] •Methane oxidation toward methanol are achieved at considerable productivity of 15975.73 μmol/gcat/h.•Tunable active species (Cu1+/0, CuxOy nanoparticles, Cu–OH motif) emerged via modulating Cu contents.•The co-existing CuxOy nanoparticles and Cu–OH motif synergistically promote methanol generation.•Reactive oxygen species produced by H2O2 take part in the reaction in a parallel way. Copper decorated zeolites are promising candidates for the partial oxidation of methane to generate methanol with elevated energy density, nevertheless, the modulation and possible synergism between multiple Cu active sites still need to be delved in depth. Here, ZSM-5 catalysts with modulated Cu motifs were proposed using copper oxysalts as precursors through a calcination process. By modifying the contents of copper oxysalts precursors, the Cu active sites varied, and a unique M shaped trend of CH3OH productivity emerged. Attributed to the synergetic effects of CuxOy nanoparticles (adsorbing CH4 and generating *OCH3 species) and Cu–OH motif (binding CH4 and forming Si···CH3), a maximum CH3OH yield of 15975.73 μmol/gcat/h (with CH3OOH yield of 2155.59 μmol/gcat/h) and methyl oxygenates selectivity up to 72.79 % could be achieved. This work paved an efficient, low cost, and succinct way for the manufacture of catalysts with tunable active sites and high performance over methane to methanol conversion.