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The Effect of Pretreatment on the Reactivity of Pd/Al2O3 in Room Temperature Formaldehyde Oxidation
ChemCatChem ( IF 4.5 ) Pub Date : 2021-08-02 , DOI: 10.1002/cctc.202101091
Lina Zhang 1 , Bangjie Zhang 1 , Peng Xue 1 , Jiwei Li 1 , Zhun Zhang 1 , Yanling Yang 1 , Shuai Wang 1 , Jingdong Lin 1 , Honggang Liao 1 , Yong Wang 2 , Yali Yao 3 , Shaolong Wan 1 , Haifeng Xiong 1
Affiliation  

A Pd/Al2O3 nanocatalyst was pretreated at 750 °C in air, Ar or H2O/Ar, respectively. The effect of these different pretreatments on the active species and reactivity of Pd/Al2O3 in formaldehyde oxidation at room temperature was investigated. The pretreatment was found to affect both the phase transformation of PdO to Pd metal and the Pd dispersion, leading to different catalytic performances. We found that the Pd/Al2O3 nanocatalyst pretreated in both Ar and H2O/Ar show 60 % and 100 % formaldehyde conversion at 25 °C, respectively, while the catalyst pretreated in air is not active under the same condition. Pretreatments in both Ar and H2O/Ar were found to facilitate the formation of metallic Pd on Pd/Al2O3 catalyst, confirmed by both experiments and calculation based on the function of the equilibrium oxygen pressure and temperature. We further found that the catalyst pretreated in H2O/Ar has higher Pd dispersion and more surface OH groups compared to that pretreated in Ar, leading to improved activity in formaldehyde oxidation.

中文翻译:

预处理对Pd/Al2O3室温甲醛氧化反应活性的影响

Pd/Al 2 O 3纳米催化剂分别在空气、Ar 或 H 2 O/Ar 中在 750 °C 下进行预处理。研究了这些不同的预处理对室温下甲醛氧化中 Pd/Al 2 O 3的活性物种和反应性的影响。发现预处理会影响 PdO 到 Pd 金属的相变和 Pd 分散,导致不同的催化性能。我们发现在 Ar 和 H 2 中预处理的 Pd/Al 2 O 3纳米催化剂O/Ar 在 25 °C 下分别显示 60% 和 100% 的甲醛转化率,而在空气中预处理的催化剂在相同条件下没有活性。发现在 Ar 和 H 2 O/Ar 中进行预处理有助于在 Pd/Al 2 O 3催化剂上形成金属 Pd ,这通过基于平衡氧压力和温度的函数的实验和计算得到证实。我们进一步发现,与在Ar 中预处理的催化剂相比,在 H 2 O/Ar 中预处理的催化剂具有更高的 Pd 分散度和更多的表面 OH 基团,从而提高了甲醛氧化的活性。
更新日期:2021-10-07
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