Two-dimensional transition metal chalcogenides (**) have attracted a lot of attention due to their unique electronic properties and highly tunable surface reactivity. **Due to its two-dimensional structure, it is possible to provide a large reactive surface. However, a well-structured *** substrate is usually inert, and its surface defects, such as unsaturated coordination atoms on the surface or edges, become catalytically active centers. At the same time, PT-based catalysts, including single crystals, nanoclusters, alloys, and electrodes, have been widely studied in heterogeneous catalysis and electrocatalysis due to their excellent catalytic properties. Despite this, the catalytic performance of PT-based catalysts is rarely explored, although they may have better chemical and structural stability than commercial PT-based catalysts. Based on this, this study aims to elucidate the catalytic performance of PT-based ***S and their potential as catalysts.
Recently,Meng-Fan Luo, ** University in TaiwanJYH-Pin Chou, Changhua Normal University, TaiwanwithChun-Liang Lin, Yang-Ming Chiao Tung University, TaiwanThe decomposition of methanol (CH3OH) on layered PTE2 (the concentration of surface defects controlled by argon ion (AR+) bombardment) was studied by different surface probe techniques under ultra-high vacuum (UHV) and near-atmospheric pressure (NAP) conditions. The results showed that the undercoordination PT (PTUC) on the surface of PTE2 was the active site of the reaction, and the adsorbed CH3OH at this site underwent dehydrogenation and C-O bond breakage, resulting in the formation of CHXO* (X=2 and 3) and CHX* (X=1 and 2) as the main intermediates, and finally gaseous molecules hydrogen, methane, water and formaldehyde were produced through various reaction pathways. On Pt single crystals or supported Pt nanoclusters, gaseous formaldehyde is rarely observed for CH3OH decomposition; At the same time, the common product Co* (or CO) from PT-based catalysts is not produced in this reaction and the pathway of C-O bond cleavage in the reaction accounts for a significant proportion (reflected in the production of a large amount of CHX*). Therefore, the catalytic properties of the PTUC site on PTE2 are different from those of typical PTs.
In addition, the reactivity is significantly dependent on the concentration of PTUC: at a small PTUC concentration (10%), the probability of decomposition of CH3OH on PTUC on surface TE vacancies (major surface defects) is high (>90%); With an increase in PTUC concentration (10% to 20%), the selectivity of CH3OH decomposition into CHXO* decreases due to structurally distinct PTUC produced by prolonged AR+ bombardment. Nevertheless, in either case, the reaction probability (80%) exceeds that of PT single crystals and PT clusters. In addition, based on the theoretical calculation results, it is confirmed that the structural effect and the electronic effect play an important role in determining the catalytic properties. In conclusion, the PTE2 surface with PTUC can be used as an excellent catalyst for the decomposition of CH3OH, and its catalytic selectivity can be controlled by different AR+ bombardment control surface structures.
investigating the role of undercoordinated pt sites at the surface of layered ptte2 for methanol decomposition. nature communications, 2024. doi: 10.1038/s41467-024-44840-z