Researchers at Oak Ridge National Laboratory (ORNL; Oak Ridge, Tenn.; www.ornl.gov) and a team of interdisciplinary scientists tripled the yield of methanol in the catalytic hydrogenation reaction of carbon dioxide by introducing hydrides into the catalyst support material. The researchers say the higher yield is “due to the direct participation of surface hydrides in the reaction, and the modified electronic property of the interfacial sites” in the hydride-containing catalyst. It is the first time anion substitution has been used in this context.
The team designed a catalyst that employed copper nanoparticles supported on a perovskite (barium titanate) to convert CO2 to methanol. Barium titanate support was chosen because it is among the few materials in which hydrogen anions (hydrides) can be incorporated to form a stable oxyhydride. Usually, hydrides are highly reactive toward air and water. In addition, the scientists hypothesized that the incorporated hydrogen anions might affect the electronic properties of the copper atom at the interface between the catalyst and support.
Source: ORNL
“A perovskite allows you to tune not only the cations almost across the periodic table, but also the anion sites,” says project head Zili Wu, leader of ORNL’s Surface Chemistry and Catalysis group. “You have a lot of tuning ‘knobs’ to understand its structure and catalytic performance.”
The ORNL research team conducted a range of characterization techniques to examine the structure of the copper, the support and the interface under real-world reaction conditions to correlate structure with performance, the ORNL team explained. Boosting the performance of hydride-containing catalysts for CO2-to-methanol conversions would enhance the portfolio of CO2-abatement technologies.
The ORNL work has been published in a recent issue of the journal Angewandte Chemie International Edition.