Formation of low-coordination Pt clusters on Al vacancy-induced CoAl layered double hydroxides-derived oxides enhances low-temperature oxidation performance of HCHO

[Display omitted] •Al vacancies induce the presence of high-load Pt in the form of low-coordinated clusters on the surface of LDO5.•Pt/LDO5 exhibits superior low-temperature catalytic oxidation activity for HCHO compared to Pt/LDO.•Both Al vacancies and Pt clusters can enhance the spin state of Co species in the support.•The direction of electron transfer between Pt clusters and the support is regulated by Al vacancies. Noble metal loading and oxygen vacancy construction are prevalent strategies to enhance catalyst performance in HCHO catalytic oxidation. For noble metal systems, most cutting-edge research focuses on single atoms, including the exploration of coexistence between single atoms and clusters, yet there are few reports on the impact of noble metal clusters with different coordinations on catalyst performance. Additionally, investigations into metal vacancies, as opposed to oxygen vacancies, are also scarce. In this work, we used CoAl layered double hydroxides (LDHs) as a precursor, which, after calcination and etching, yielded derived oxides with Al vacancies (LDO5). Pt was then loaded onto the surface of these oxides via impregnation (Pt/LDO5). Activity tests demonstrated that Pt/LDO5 exhibited superior HCHO oxidation activity, especially at low temperatures, compared to Pt/LDO. Utilizing high-resolution transmission electron microscopy (HRTEM) and X-ray absorption fine structure (XAFS), we discovered that, in contrast to the “standard” Pt clusters on the LDO surface, Pt primarily existed as low-coordination clusters on the LDO5 surface, even with a higher Pt loading. Moreover, the coexistence of Al vacancies and low-coordination Pt clusters effectively enhanced the spin state of Co species in the support and altered the direction of electron transfer between Pt and the support.