液相原位还原法制备钯基催化剂

Preparation of Pd-based catalysts by liquid phase in-situ reduction method

采用液相原位还原法制备Pd/α-Al2O3催化剂,并应用于CO氧化偶联合成草酸二甲酯反应。对比实验发现,甲醛液相原位还原法制得的Pd基催化剂具有优异的催化活性,当Pd负载质量分数低至0.1%时,催化剂仍表现出较高的活性和稳定性。采用XRD和BET等对催化剂及载体进行表征,结果表明,催化剂活性与载体的比表面积、孔容和孔径没有必然联系。通过TEM发现,0.1%-Pd/α-Al2O3催化剂中的主要活性组分Pd具有较小的颗粒和较高的分散性,通过HRTEM发现,液相原位还原法制备的催化剂能够有效暴露出Pd(111)晶面。

Pd/α-Al2O3 catalysts were prepared by liquid phase in-situ reduction method, and were applied in CO oxidative coupling to dimethyl oxalate （DMO）. The results showed that the as-prepared Pd/α-Al2O3 catalysts possessed excellent catalytic activity, and the catalyst with Pd loading mass fraction of 0.1% still exhibited higher activity and stability. Pd/α-Al2O3 catalysts and the support were characterized by BET and TEM. The characterization results indicated that the specific surface area, pore volume and pore size of the support were not associated with the activity of the catalysts. The active component Pd particles on 0.1%-Pd/α-Al2O3 catalyst had high dispersion and small sizes, and it was further found by HRTEM that 0.1% -Pd/α-Al2O3 catalyst effectively exposed Pd （ 111 ） facets, which were reactive facets for CO oxidative coupling to DMO.