Manipulating the Surface Oxygen Vacancies of the Nanosized ZrO<sub>2</sub> Carrier for Co-Catalyzed Fischer–Tropsch Synthesis
Miao Jin, Bing Xu, Jun Ma, Chengcheng Yi, Yuefeng Liu
Abstract
Fischer–Tropsch synthesis is a typical reaction for converting synthesis gas ( i.e., CO and H 2 mixture) to clean fuels, by coupling different processes, which can produce products such as engine fuels and other high value-added chemicals. However, searching for a suitable catalyst is still challenging due to its chemical structure-sensitive properties, which greatly affect the interaction with active components, thereby altering the reaction activity or product selectivity. In this work, the nanosized ZrO 2 with different oxygen vacancy concentrations was synthesized by using UiO-66 as a precursor and applied for supporting cobalt nanoparticles. The results showed that treatment of nanosized ZrO 2 carrier with diluted nitric acid at an appropriate temperature could effectively modulate its surface oxygen vacancy and subsequently alter the FTS activity. The optimized Co/C-ZrO 2 -80 catalyst with a high concentration of oxygen vacancy displayed a CO conversion of 44.2% and a cobalt time yield (CoTY) of 20.9 × 10 –5 mol CO g Co –1 s –1 at 220 °C, which shows a 2.9-fold increase in CoTY compared with the conventional ZrO 2 -supported catalyst. Multiple characterizations and comparative experiments indicated that oxygen vacancies on the surface of ZrO 2 enhanced the electron transfer and the interaction between Zr and Co species. Zr-O V -Co interface sites promoted the adsorption and dissociation of CO and H 2 molecules. This work provides a new perspective for studying the effect of oxygen vacancies on the structure and reactivity of cobalt-based FTS catalysts.