Manipulating the Surface Oxygen Vacancies of the Nanosized ZrO2 Carrier for Co-Catalyzed Fischer–Tropsch Synthesis

Fischer–Tropsch synthesis is a typical reaction for converting synthesis gas (i.e., CO and H2 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 ZrO2 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 ZrO2 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-ZrO2-80 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 molCO gCo–1 s–1 at 220 °C, which shows a 2.9-fold increase in CoTY compared with the conventional ZrO2-supported catalyst. Multiple characterizations and comparative experiments indicated that oxygen vacancies on the surface of ZrO2 enhanced the electron transfer and the interaction between Zr and Co species. Zr-OV-Co interface sites promoted the adsorption and dissociation of CO and H2 molecules. This work provides a new perspective for studying the effect of oxygen vacancies on the structure and reactivity of cobalt-based FTS catalysts.