Low-temperature direct conversion of methane to methanol over carbon materials supported Pd-Au nanoparticles

• Published in: Catalysis today 2020-01, Vol.339, p.48-53
• Main Authors: He, Yingluo, Luan, Chunhui, Fang, Yuan, Feng, Xiaobo, Peng, Xiaobo, Yang, Guohui, Tsubaki, Noritatsu
• Format: Article
• Language: English
• Subjects: Carbon material; Functional groups; Methane oxidation; Methanol; Pd-Au nanoparticle
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2019.02.043

[Display omitted] •The Pd-Au nanoparticles supported on carbon materials catalysts were prepared.•Carbon supported Pd-Au catalysts show excellent reaction performance.•A suitable (O2+H2)/CH4 ratio enhances the methanol productivity.•Functional groups on the surface of CNTs affect the catalytic performance.•The interaction between Pd-Au and carbon supports shows an important effect to methane activation. Direct conversion of methane to methanol under mild conditions remains a great challenge. Here, we report a class of carbon material catalysts for this direct synthesis. The carbon materials such as carbon nanotubes (CNTs), activated carbon (AC), and reduced graphene oxide (rGO) are employed as catalyst support, and the palladium-gold (Pd-Au) nanoparticles are used as active center. By using oxygen/hydrogen as oxidant in the direct synthesis, the catalyst of Pd-Au/CNTs shows outstanding methanol productivity and selectivity. Compared with the Pd-Au/CNTs, the Pd-Au/CNTs-n with a treatment of nitric acid for the support enhances the methanol selectivity, but decreases the methanol productivity. In addition, our characterization results reveal that a weak interaction between Pd-Au nanoparticles and CNTs support is in favor of methanol productivity and selectivity. In contrast, a strong interaction between Pd-Au and AC or rGO catalysts inhibits the reaction activity. This work offers a simple and effective strategy to directly synthesize methanol from methane under the mild conditions.