Significant progress has been made in the research on fuel cell catalyst design at the Shanxi Coal Chemistry Institute

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Significant progress achieved in the research on fuel cell catalyst design at Shanxi Institute of Coal Chemistry. Author/Source: Date: 2019-08-23 Clicks: 77 Direct methanol fuel cells (DMFCs) have attracted widespread attention due to their high energy density, ease of transportation and storage, and low level of pollution. However, the extensive use of Pt-based catalysts in DMFCs makes them expensive, and at the same time, Pt is prone to deactivation due to poisoning by intermediates in the methanol oxidation reaction (especially CO), which severely limits the commercialization of DMFCs. Among the existing strategies for enhancing the activity and resistance to poisoning of Pt-based catalysts, as well as for producing Pt-based catalysts that are low-cost and highly stable, designing appropriate catalyst supports represents the simplest and most effective method to achieve large-scale DMFC production without altering the existing catalyst manufacturing techniques. To this end, researchers at home and abroad are continuously developing various advanced carriers to achieve excellent performance. 　　Recently, the research team led by Tong Xili from the Shanxi Institute of Coal Chemistry, building on their long-term research on silicon carbide, discovered that using nano-silicon carbide carriers can significantly reduce the amount of Pt required while maintaining its activity (more than 3 times that of commercial Pt/C catalysts), and it also enhances the catalyst’s resistance to CO poisoning (Figure 1). The specific process involves using CCl4 for dry etching of the Si atoms on the SiC surface, thereby generating an ultra-thin carbon layer in situ on that surface; the thickness of this carbon layer is controlled by the etching time. This material supports Pt catalysts and exhibits excellent catalytic performance for methanol oxidation (MOR). It was also found that as the carbon layer thickens, the catalyst’s ability to oxidize methanol improves significantly, while its resistance to CO poisoning and stability are also markedly enhanced. DFT calculations to study its reaction mechanism show (Figure 2) that as the surface carbon layer thickens, the adsorption energy of CO on the catalyst Pt decreases significantly, thereby reducing the catalyst’s poisoning by CO ； At the same time, the adsorption energy of OH increases, facilitating the oxidation of methanol molecules adsorbed on the Pt surface and thereby significantly enhancing its activity. 　　This research was funded and supported by projects such as the **National Natural Science Foundation. The related work was published as a cover article in the journal Small, DOI: 10.1002/smll.201902951.