<p>Carbon dioxide (CO<sub>2</sub>) is the main gas responsible for the greenhouse effect. Anthropogenic activities have increased the concentration of this gas in the atmosphere in recent years, intensifying the greenhouse effect and resulting in anomalous climate phenomena. CO<sub>2</sub> recycling technologies have been developed with the aim of reducing the impacts of this gas on climate change. Catalytic hydrogenation of CO<sub>2</sub> for the generation of products of commercial interest, such as methanol (CH<sub>3</sub>OH) and ethanol (C<sub>2</sub>H<sub>5</sub>OH), for example, is a technology that has attracted the attention of recent research, given the wide industrial applicability of these alcohols and the possibility of carbon recycling. In the present study, CO<sub>2</sub> hydrogenation reaction was investigated to produce alcohols using catalysts based on cobalt, copper and a combination between cobalt and copper. It was observed that CuO-Co<sub>3</sub>O<sub>4</sub>-Al<sub>2</sub>O<sub>3</sub> catalysts with different Co:Cu mass ratios have improved methanol productivity when compared to CuO-Al<sub>2</sub>O<sub>3</sub> or Co<sub>3</sub>O<sub>4</sub>-Al<sub>2</sub>O<sub>3</sub>. Furthermore, the promotion of Co<sub>3</sub>O<sub>4</sub>-Al<sub>2</sub>O<sub>3</sub> by 2 wt% Na, K, Rb or Cs showed better catalytic performance for the formation of ethanol, increasing its productivity up to 25 times compared to the non-promoted cobalt catalyst. The highest ethanol productivity in the present work, corresponding to 5.3&#xa0;µmol/g<sub>cat</sub>.h, was achieved using the 2 wt% K-Co<sub>3</sub>O<sub>4</sub>-Al<sub>2</sub>O<sub>3</sub> catalyst under the reaction conditions of T = 220&#xa0;°C, P = P<sub>atm</sub> and GHSV = 24,000&#xa0;mL/g<sub>cat</sub>.h.</p>

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Study of the CO2 hydrogenation reaction for the synthesis of alcohols on Cu and Co-based catalysts

  • Francisco Marcelo dos Santos de Oliveira,
  • Janaina Fernandes Gomes

摘要

Carbon dioxide (CO2) is the main gas responsible for the greenhouse effect. Anthropogenic activities have increased the concentration of this gas in the atmosphere in recent years, intensifying the greenhouse effect and resulting in anomalous climate phenomena. CO2 recycling technologies have been developed with the aim of reducing the impacts of this gas on climate change. Catalytic hydrogenation of CO2 for the generation of products of commercial interest, such as methanol (CH3OH) and ethanol (C2H5OH), for example, is a technology that has attracted the attention of recent research, given the wide industrial applicability of these alcohols and the possibility of carbon recycling. In the present study, CO2 hydrogenation reaction was investigated to produce alcohols using catalysts based on cobalt, copper and a combination between cobalt and copper. It was observed that CuO-Co3O4-Al2O3 catalysts with different Co:Cu mass ratios have improved methanol productivity when compared to CuO-Al2O3 or Co3O4-Al2O3. Furthermore, the promotion of Co3O4-Al2O3 by 2 wt% Na, K, Rb or Cs showed better catalytic performance for the formation of ethanol, increasing its productivity up to 25 times compared to the non-promoted cobalt catalyst. The highest ethanol productivity in the present work, corresponding to 5.3 µmol/gcat.h, was achieved using the 2 wt% K-Co3O4-Al2O3 catalyst under the reaction conditions of T = 220 °C, P = Patm and GHSV = 24,000 mL/gcat.h.