Role of percentage of {0 0 1} crystal facets in TiO2 supports toward the water–gas shift reaction over Au-TiO2 catalysts

Support effects always attract extensive interesting in heterogenous catalysis. However, the same supports might not show same effects on different catalytic reactions, even the opposite. Here, we quantitatively analyzed the role of the percentage of {0 0 1} facets toward the water–gas shift (WGS) catalytic performances over Au-TiO2 catalysts. With increasing HF, the percentage of {0 0 1} gradually increase, while their catalytic activities gradually decrease following the sequence: Au-TiO2-HF0 > Au-TiO2-HF3 > Au-TiO2-HF9. For cyclic stability, Au-TiO2-HF0 showing somewhat low stability is due to increase in percentage of {0 0 1}, while Au-TiO2-HF3 and Au-TiO2-HF9 having high stability is because of decrease in the percentage of {0 0 1} albeit Au particle sintering. Accordingly, WGS activities of both fresh and used catalysts have good linear correlation with the percentage of {0 0 1} (negative correlation), the percentage of oxidized gold species (positive correlation) and the hydrogen consumption (positive correlation).