Pt/Ba/Al₂O₃ has been extensively used as a NO_x storage and reduction (NSR) catalyst to remove nitrogen oxides (NO_x) in lean-burn engine exhausts, but 1-2 wt % platinum loading in Pt/Ba/Al₂O₃ makes it quite expensive.

Moreover, Pt/Ba/Al₂O₃ readily undergoes severe deactivation owing to sulfur poisoning and thermal aging, resulting in loss of catalytic activity and decline of the NO_x removal efficiency. It is of great challenge to develop an alternative possessing high sulfur tolerance and low dependence on precious metals without sacrificing its capabilities.

Prof. WANG Ruihu’s research group at Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, has reported a highly efficient and low-cost Cu/Ba/bauxite (1 wt% Cu and 16 wt% Ba) catalyst for NO_x removal in the exhaust of lean-burn engine.

The catalyst uses the post-treated natural bauxite as a support. Bauxite is much cheaper and readily available. The natural source of the bauxite may result in good thermal stability of Cu/Ba/bauxite. The components, such as Al₂O₃, FeO_x, TiO₂, CaO, SiO₂ and trace of platinum, are beneficial for NSR and the resistance against sulfur poisoning. In comparison with traditional Pt/Ba/Al₂O₃ (1 wt% Pt and 16 wt% Ba), Cu/Ba/bauxite shows superior NSR performances, outstanding sulfur resistance and thermal stability without the addition of extra platinum.

The most important thing is that the price of Cu is less than 1% price of Pt, thus, Cu/Ba/bauxite is much cheaper than Pt/Ba/Al₂O₃ owing to the absence of Pt addition, the application of Cu/Ba/bauxite will greatly cut down the catalysts cost in NO_x removal of learn-burn engines.

Results of this study have been published on Scientific Reports, 2013, 3, 1559; DOI: 10.1038/srep01559.

 

CONTACT:

Prof. WANG Ruihu

Fujian Institute of Research on the Structure of Matter

Chinese Academy of Sciences

Email: ruihu@fjirsm.ac.cn