Abstract：
Metal oxides derived from layered double hydroxides (LDHs) are expected to obtain low-temperature denitrification (de-NOx) catalysts with high catalytic activity and H2O/SO2 tolerance in the selective catalytic reduction (SCR) of NOx with NH3. In current work, we successfully prepared Gd-modified Mn-Co metal oxides derived from Gd-modified Mn-Co LDHs. The resultant Gd-modified Mn-Co metal oxides exhibit excellent catalytic activity and high H2O/SO2 tolerance in the NH3-SCR de-NOx reaction. The reasons for the enhancement can be ascribed to the unique surface physicochemical properties inherited from LDHs and the modification of Gd, which increase the specific surface area, improve the relative content of Mn4+ and Co3+ on the surface, enhance the number of acidic sites, strengthen the reducibility of catalyst, resulting in the enhanced catalytic activity and H2O/SO2 tolerance. Additionally, it is demonstrated that the NH3-SCR de-NOx reaction occurred on the surface of Gd-modified Mn-Co oxides followed both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. This study provides us with a design approach to promote catalytic activity and H2O/SO2 tolerance through morphology control and rare earth modification.
摘要：
由层状双氢氧化物（LDH）衍生的金属氧化物有望在NH3对NOx的选择性催化还原（SCR）中获得具有高催化活性和H2O/SO2耐受性的低温脱氮（de-NOx）催化剂。在目前的工作中,我们成功地制备了Gd改性Mn-CoLDHs衍生的Gd改性Mn-Co金属氧化物。所得Gd改性的Mn-Co金属氧化物在NH3-SCR脱NOx反应中表现出优异的催化活性和高的H2O/SO2耐受性。增强的原因可以归因于LDHs继承的独特的表面物理化学性质和Gd的修饰，增加了比表面积，提高表面Mn4+和Co3+的相对含量，增加酸性位点的数量，加强催化剂的还原性，提高了催化活性和H2O/SO2耐受性。此外,结果表明，Gd改性的Mn-Co氧化物表面发生的NH3-SCR脱NOx反应遵循Eley-Rideal（E-R）和Langmuir-Hinshelwood（L-H）机理。本研究为我们提供了一种通过形态控制和稀土改性来提高催化活性和H2O/SO2耐受性的设计方法。
