Up-scaled flash nano-precipitation production route to develop a MnOx–CeO2–Al2O3 catalyst with enhanced activity and H2O resistant performance for NOx selective catalytic reduction with NH3

A Critical Review of Recent Progress and Perspective in Practical Denitration Application

Nitrogen oxides (NOx) represent one of the main sources of haze and pollution of the atmosphere as well as the causes of photochemical smog and acid rain. Furthermore, it poses a serious threat to human health. With the increasing emission of NOx, it is urgent to control NOx. According to the different mechanisms of NOx removal methods, this paper elaborated on the adsorption method represented by activated carbon adsorption, analyzed the oxidation method represented by Fenton oxidation, discussed the reduction method represented by selective catalytic reduction, and summarized the plasma method represented by plasma-modified catalyst to remove NOx. At the same time, the current research status and existing problems of different NOx removal technologies were revealed and the future development prospects were forecasted.

High CO Methanation Performance of Two-Dimensional Ni/MgAl Layered Double Oxide with Enhanced Oxygen Vacancies via Flash Nanoprecipitation

As a methanation tool, two-dimensional (2D) carrier-loaded Ni has attracted the attention of many researchers. We successfully prepared 2D MgAl layered double oxides (LDO) carriers via flash nanoprecipitation (FNP). Compared to the LDO samples prepared by conventional co-precipitation (CP), the 2D MgAl-LDO (FNP) has more oxygen vacancies and more exposed active sites. The Ni/MgAl-LDO (FNP) catalyst demonstrates a CO conversion of 97%, a CH4 selectivity of 79.8%, a turnover frequency of 0.141 s−1, and a CH4 yield of 77.4% at 350 °C. The weight hourly space velocity was 20,000 mL∙g−1∙h−1 with a synthesis gas flow rate of 65 mL∙min−1, and a pressure of 1 atm. A control experiment used the CP method to prepare Ni/MgAl-LDO. This material exhibits a CO conversion of 81.1%, a CH4 selectively of 75.1%, a TOF of 0.118 s−1, and a CH4 yield of 61% at 450 °C. We think that this FNP method can be used for the preparation of more 2D LDO catalysts.

Enhanced Oxygen Vacancies in a Two-Dimensional MnAl-Layered Double Oxide Prepared via Flash Nanoprecipitation Offers High Selective Catalytic Reduction of NOx with NH₃

A two-dimensional MnAl-layered double oxide (LDO) was obtained by flash nanoprecipitation method (FNP) and used for the selective catalytic reduction of NOx with NH₃. The MnAl-LDO (FNP) catalyst formed a particle size of 114.9 nm. Further characterization exhibited rich oxygen vacancies and strong redox property to promote the catalytic activity at low temperature. The MnAl-LDO (FNP) catalyst performed excellent NO conversion above 80% at the temperature range of 100⁻400 °C, and N₂ selectivity above 90% below 200 °C, with a gas hourly space velocity (GHSV) of 60,000 h-1, and a NO concentration of 500 ppm. The maximum NO conversion is 100% at 200 °C; when the temperature in 150⁻250 °C, the NO conversion can also reach 95%. The remarkable low-temperature catalytic performance of the MnAl-LDO (FNP) catalyst presented potential applications for controlling NO emissions on the account of the presentation of oxygen vacancies.