title: Chlorine as an indicator in the controllable preparation of active nano-gold catalyst.
abstract: The controllable preparation of nano-gold catalyst maintains a challenge. Except the parameters have been revealed before, here we'd like to show that controllable preparation of active nano-gold catalyst can be achieved using chlorine as an indicator. By tracing the chlorine concentration in the washing step, a series of Au/Fe2O3 catalysts were prepared with co-precipitation method. The applying of these catalysts in CO oxidation and reductive nitrobenzene N-alkylation suggested the active catalysts were prepared from solutions containing ~2 ppm chlorine. The catalytic activity dropped dramatically if the chlorine concentration is >4-6 or ≪1 ppm. Extensive characterizations revealed that the active catalyst was composed by nano-gold on the edge of Fe2O3 particle with 8.92 Au-Au coordination numbers. Although the real role of chlorine in the variation of catalyst structure and activity was still ambiguous, the current results should promote the controllable preparation of active nano-Au catalyst.
authors.affiliation: Centre for Green Chemistry and Catalysis, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.
authors.forename: Chengming
authors.initials: C
authors.lastname: Zhang
authors.forename: Lequan
authors.initials: L
authors.lastname: Liu
authors.forename: Xinjiang
authors.initials: X
authors.lastname: Cui
authors.forename: Lirong
authors.initials: L
authors.lastname: Zheng
authors.forename: Youquan
authors.initials: Y
authors.lastname: Deng
authors.forename: Feng
authors.initials: F
authors.lastname: Shi