Investigation On Low-temperature NH₃-SCR Performance Of Copper-based Oxide Catalyst Derived From Cu-BTC And Its Modified Precursor

The ammonia selective catalytic reduction（NH₃-SCR）technology is currently the most widely used nitrogen oxide（NO_x）control technology.In the application and development of its catalyst,the Cu-based oxide catalyst as an excellent metal oxide denitration catalyst has been in-depth research in the field of low-temperature SCR.At the same time,Catalysts prepared with metal organic framework materials（MOFs）as precursors have better redox performance and more dispersed metal active centers.The preparation of high-performance Cu-based oxide denitration catalysts using Cu-based MOFs as precursors is an important research direction.This article focuses on a Cu-based MOFs material:Cu-BTC,to investigate the effects of different calcination methods,surfactant modification,and TiO₂ coating on the SCR performance of its derivative catalysts.The main research conclusions are as follows:（1）Different calcination methods have a certain influence on the NH₃-SCR performance of the catalyst.The CuO_x-N₂ catalyst obtained by first carbonizing under nitrogen and then oxidizing under air contains a small amount of carbon material and has a CuO/Cu₂O heterostructure,showing good denitrification activity（in the temperature range of 200-240℃,the catalyst can convert NO_x Rate exceeds 80%）.（2）Further improve the activity of the catalyst through surfactant modification.The study found that the catalyst samples derived from Cu-BTC precursor materials modified by surfactants can maintain the mixed crystal phase of CuO and Cu₂O.Different types of surfactants and their added amount have a certain impact on the NH₃-SCR performance of the catalyst.The CuO_x-F127-1 catalyst has the best denitration performance among the surfactant modified series catalysts（NO_x conversion rate can reach more than 80%in the range of 180-240℃）.The addition of F127 makes the catalyst form a carbon material shell,thereby reducing the deposition of sulfates and inhibiting the formation of copper sulfate species,and improving the SO₂ resistance of the catalyst.Higher strong acid sites and total acid content,higher O_αcontent and more suitable Cu⁺/Cu²⁺synergy may play a crucial role in the NH₃-SCR reaction.（3）TiO₂ coating can increase the medium and high temperature activity and sulfur resistance of the catalyst.By controlling the amount of ammonia added,the amount of TiO₂coating on the surface of the Cu-BTC material can be controlled,which will have a certain impact on the NH₃-SCR performance of the catalyst.The CuO_x@TiO₂-1 catalyst has the best denitration performance（NO_x conversion rate can reach more than 80%in the range of 190-280℃）.The presence of TiO₂ greatly increases the number of acidic sites of the catalyst,the catalyst’s ability to adsorb NH₃ is enhanced,and the corresponding high-temperature activity is improved.The coating of CuO_x by the TiO₂ shell effectively reduces the catalyst’s adsorption of SO₂,so that CuO_x@TiO₂-1 catalyst showed better SO₂ resistance in the SO₂ resistance test.