Au on in 2 O 3‐x /TiO 2 (110): A Highly Active and Selective Catalyst for the Conversion of CO
Kasala Prabhakar Reddy, Anas Mahmud, Pedro J. Ramírez, Arephin Islam, Irene Barba‐Nieto, Zahir Faruqi, Adrian Hunt, Iradwikanari Waluyo, José A. RodriguezABSTRACT
Methanol production by carbon dioxide hydrogenation is a promising route for supplying industrial fuel demands, but achieving high methanol selectivity remains challenging due to competing favorable reactions. Here, we investigate model Au/In 2 O 3‐x /TiO 2 (110) catalysts to elucidate the roles of metal‐oxide and oxide‐oxide interactions in CO 2 conversion. Using a combination of ambient‐pressure X‐ray photoelectron spectroscopy (AP‐XPS), temperature‐programmed desorption (TPD), and catalytic measurements, we show that small coverages of Au (<0.15 monolayer) dispersed on In 2 O 3‐x /TiO 2 (110) significantly enhance both CO 2 and H 2 activation at low temperatures (300–400 K). The Au/In 2 O 3‐x /TiO 2 (110) systems exhibit superior catalytic performance, with the highest methanol selectivity (∼80–85%) and increased conversion rates compared to In 2 O 3‐x /TiO 2 (110) and Au/TiO 2 (110). Spectroscopic results showed that Au nanoparticles promote the formation of oxygen vacancies and enhance CO 2 activation, without inducing the dissociation of methoxy and methanol. Reaction studies support a formate‐mediated reaction pathway, distinct from the CO‐mediated route observed on Au/TiO 2 catalysts that leads to very low methanol selectivity. Oxide‐oxide interactions stabilized the partially reduced In 2 O 3‐x , and prevented Au‐In alloy formation under CO 2 +H 2 conditions, preserving methanol selectivity. These findings highlight the importance of synergistic metal↔oxide‐oxide interactions when designing efficient catalysts for selective hydrogenation of CO 2 to methanol while minimizing the content of Au and In 2 O 3‐x .