Effect of various precipitants on activity and thermal stability of CuFe₂O₄ water-gas shift catalysts

Three kinds of CuFe₂O₄ catalysts were synthesized by co-precipitation method using potassium hydroxide (A), sodium carbonate (B) and sodium bicarbonate (C) as the precipitants. Their catalytic activity and thermal stability were evaluated in water-gas shift reaction (WGSR). The microstructure and surface property of as-prepared catalysts was investigated by X-ray diffraction (XRD), N₂-physisorption, H₂-temperature programmed reduction (H₂-TPR), CO₂-temperature programmed desorption (CO₂-TPD) and cyclic voltammetry (CV). The results show that the catalyst prepared with potassium hydroxide as precipitant exhibits excellent WGSR activity. Potassium hydroxide plays an important role in promoting the generation of CuFe₂O₄, restraining growth of crystalline CuO and CuFe₂O₄, resulting in much better dispersion of CuO on the surface of catalysts, enhancing the reducibility of catalysts, and increasing the amount of weak basic sites. These factors remarkably improve the activity and thermal stability of catalysts.