| The emission of nitrogen oxides (NOx) seriously pollutes the ecological environment and endangers human health, therefore reducing NOx emission is an important techoque. Selective catalytic reduction of NOx by hydrogen (H2-SCR), as a highly effiecent de-NOx method, has received extensive attention. Precious metals, particularly Palladium, are considered to be the key active components in the H2-SCR process. Pd exhits great catalytic activity in the reduction of NOx by hydrogen, and is cheaper than rhodium. In this paper, the latest research progress on Pd-based catalysts for NOx reduction by H2-SCR in the past 10 years has been reviewed, including the possible mechanisms of H2-SCR reaction and the effects of preparation processes, supports, additives and flue gas components on the reduction of NOx. The current difficulties and challenges were also analyzed. It is proposed that future research should focus on the development of low loaded Pd-based composite catalysts with double or multi-active centers to endow the catalysts with water-resistant and sulfur-resistant ability. |
