Decomposition Kinetics of H2O2 on Pd Nanocrystals with Different Shapes and Surface Strains

Abstract

AbstractDirect synthesis of hydrogen peroxide (H2O2) from H2 and O2 on a Pd‐based catalyst has emerged as a promising route to replace the energy‐consuming, highly inefficient anthraquinone process. However, Pd is also a good catalyst for the decomposition of H2O2, thereby compromising the selectivity toward the desired product. The coupling between the formation and decomposition reactions makes it difficult to single out the most important parameter that controls the selectivity toward direct synthesis of H2O2. Herein, support‐free monometallic Pd nanocrystals with different shapes and surface strains are used to investigate their impacts on the decomposition kinetics of H2O2. The kinetics are analyzed by tracking the concentration of the remaining H2O2 using infrared spectroscopy. The data indicates that both surface structure and strain affect the decomposition kinetics of H2O2, but their impacts are inferior to that caused by Br−, a surface capping agent for the Pd{100} facets. The experimental results are consistent with the trend obtained through density functional theory calculations. This work helps shed light on the development of Pd‐based catalysts for the direct synthesis of H2O2 by offering strategies to mitigate the decomposition of the desired product.