Low-temperature water gas shift reaction catalyst with novel gold active species, and preparation method thereof

Abstract

The invention discloses a low-temperature water gas shift reaction catalyst with a novel gold active species, and a preparation method thereof. The preparation method comprises the following steps: adjusting the synthesis process of zinc-titanium hydrotalcite, synthesizing a zinc-titanium hydrotalcite precursor with a perfect crystal form, calcining the precursor, loading urea by using a urea precipitation deposition process, and carrying out low reduction temperature pretreatment to obtain the novel gold-based catalyst Au@TiO2-x / ZnO with highly uniformly dispersed Au particles. The novel goldactive species Au<delta-> contained in the catalyst and the unique Au<delta->-Ov-Ti<3+> active site structure of the catalyst participate in the catalytic shift reaction of water gas, so the catalytic activity of the catalyst in the invention in the shift reaction of the water gas is greatly higher than that of a conventional Au / TiO2 system. A series of in situ means adopted in the invention proves that the active species is the active site during the actual reaction.

Description

technical field [0001] The invention belongs to the technical field of preparation of nanometer metal material catalysts, and in particular relates to a low-temperature water gas shift reaction catalyst with novel gold active species and its preparation method and identification method. Background technique [0002] water gas shift reaction It is an important chemical industrial reaction to produce high-purity hydrogen for fuel cells, selective hydrogenation or ammonia synthesis. Since WGSR is an exothermic process, a higher reaction temperature has a thermodynamically adverse effect on the forward reaction, and a lower reaction temperature favors the conversion of CO, but at the expense of kinetics. To better utilize the thermodynamic and kinetic advantages, supported gold-based catalytic systems such as Au / TiO 2 , Au / CeO 2 and Au / FeO x , have aroused intense interest due to their excellent catalytic performance for the water-gas shift reaction at relatively low temper...

AI Technical Summary

Problems solved by technology

However, due to the high surface energy and low Tammann temperature of Au, supported Au nanoparticles are usually thermodynamically unstable and tend to minimize their surface energy by agglomeration during long-term use or even storage.

In addition, the active species of gold in the water gas shift reaction is still unclear, and the precise modulation of the active sites of supported Au catalysts has been a great challenging goal.

Images