Fig. 5: Validation of a hypothesis for the influence on the mobility of the Mo species enabled by adding Pt-Bi alloy into the Mo/ZSM5 catalyst. | Nature Communications

Fig. 5: Validation of a hypothesis for the influence on the mobility of the Mo species enabled by adding Pt-Bi alloy into the Mo/ZSM5 catalyst.

From: Direct conversion of methane to aromatics and hydrogen via a heterogeneous trimetallic synergistic catalyst

Fig. 5

A, B Schematic diagrams of the changes in acidic proton-Mo sites and Brønsted acid sites (BASs) as the ratio of Si/Al increases from 25 to 140 on Mo/ZSM-5 catalyst. The red and blue dashed boxes highlighted that acidic proton-Mo sites and BASs disappeared, respectively. Mo species move from BASs to the external surface of ZSM-5 as green dashed box is highlighted. C Schematic diagram of two possible cases for Pt-Bi/Mo/ZSM-5 catalyst: (1) Pt-Bi alloy reduces the mobility of Mo oxides (red dashed box) or (2) Pt-Bi alloy promotes Mo oxides migration to the zeolite surface (green dashed box). D Benzene relative selectivity for Mo and Pt-Bi/Mo catalysts with different ratios of Si/Al. Color scheme: Mo (cyan-blue), Bi (purple), Si (yellow), Al (pink), H (blue), O (red) and Pt (white).

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