Revealing the relationship between the catalytic performance of Pt/SiO₂ catalysts and the electron density of Pt assisted by [HMIM][BF₄]

By regulating the electron density of metals to reveal the relationship between the electronic structure and the catalytic performance is of vital importance in catalytic science. However, traditional modulation methods, such as alloying and doping, can always inadvertently cause the reconstruction of metals and even generate new active sites. Acidic ionic liquid (AIL) has strong electron-donating ability but minimal influence on the morphology of metals. In this work, [HMIM][BF₄] was chosen as the electron donator to regulate the electron density of Pt clusters. After [HMIM][BF₄] modification onto Pt clusters, Pt clusters morphology is almost unchanged. And with the increasing modification amount of [HMIM][BF₄], the electron density of Pt clusters increased orderly. In the selective hydrogenation of phenylacetylene, both the conversion and the selectivity to styrene were improved after appropriate concentration of [HMIM][BF₄] modification. By connecting apparent activation energy and binding energy, a linear correlation is present. Thus, it is the [HMIM][BF₄] modification that increases Pt clusters’ electron density, thereby improving the catalytic performance of the catalysts. This work opens up an alternative thoroughfare to only regulate the electron density of the metals with no other change.