Subhan Fazle, Aslam Sobia, Yan Zifeng, Yaseen Muhammad
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China; Department of Chemistry, Abdul Wali Khan University Mardan, K.P. Pakistan.
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China; Department of Chemistry, Abdul Wali Khan University Mardan, K.P. Pakistan.
J Colloid Interface Sci. 2020 Oct 15;578:37-46. doi: 10.1016/j.jcis.2020.05.093. Epub 2020 May 27.
Palladium based catalysts are highly attractive for catalytic reactions. However, the catalytic activity is dependent on the dispersion and size of Pd nanoparticles (NPs). Herein, an efficient strategy is developed to regulate the size and dispersion of Pd NPs in nanoconfined spaces provided by Santa Barbara Amorphous-15 (SBA-15) occluded with template. The Pd precursor is introduced to the confined spaces between the template and silica walls in as-synthesized SBA-15 (AS) by grinding. Subsequent reduction allow template removal and precursor conversion to Pd in single step and avoids aggregation that take place in calcined SBA-15 (CS). Our results show that up to 1.0 wt% of Pd can be well dispersed in confined spaces of AS (denoted as 1.0PdAS), while sever aggregation take place from CS with the same Pd loading (denoted as1.0PdCS). We also demonstrated that 1.0PdAS is highly efficient for catalytic reduction of p-nitrophenol (P-NP) and Methylene blue (MB) with rate constant of 0.4924 and 0.626 min, respectively, which is superior than 1.0PdCS attributed to well dispersed and smaller size (3 nm) Pd NPs. Furthermore, no change in the rate constant of P-NP (0.4924 min) and MB (0.626 min) after regeneration presents good stability of 1.0PdAS in catalytic reactions.
钯基催化剂对催化反应极具吸引力。然而，催化活性取决于钯纳米颗粒（NPs）的分散度和尺寸。在此，我们开发了一种有效策略，用于调控在被模板封堵的圣巴巴拉无定形-15（SBA-15）提供的纳米受限空间内钯纳米颗粒的尺寸和分散度。通过研磨将钯前驱体引入到合成态SBA-15（AS）中模板与二氧化硅壁之间的受限空间。随后的还原过程一步实现了模板去除和前驱体转化为钯，避免了在煅烧态SBA-15（CS）中发生的聚集现象。我们的结果表明，高达1.0 wt%的钯能够很好地分散在AS的受限空间中（记为1.0PdAS），而相同钯负载量的CS（记为1.0PdCS）则发生了严重聚集。我们还证明，1.0PdAS对催化还原对硝基苯酚（P-NP）和亚甲基蓝（MB）具有高效性，其速率常数分别为0.4924和0.626 min⁻¹，这优于1.0PdCS，这归因于钯纳米颗粒分散良好且尺寸较小（3 nm）。此外，再生后P-NP（0.4924 min⁻¹）和MB（0.626 min⁻¹）的速率常数没有变化，表明1.0PdAS在催化反应中具有良好的稳定性。
