Unusual Pd nanoparticle dispersion in microenvironment for p-nitrophenol and methylene blue catalytic reduction

Fazle Subhan; Sobia Aslam; Zifeng Yan; Muhammad Yaseen

doi:10.1016/j.jcis.2020.05.093

Unusual Pd nanoparticle dispersion in microenvironment for p-nitrophenol and methylene blue catalytic reduction

J Colloid Interface Sci. 2020 Oct 15:578:37-46. doi: 10.1016/j.jcis.2020.05.093. Epub 2020 May 27.

Authors

Fazle Subhan¹, Sobia Aslam², Zifeng Yan³, Muhammad Yaseen⁴

Affiliations

¹ 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. Electronic address: fazle@awkum.edu.pk.
² 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.
³ State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China. Electronic address: zfyancat@upc.edu.cn.
⁴ Institute of Chemical Sciences, University of Peshawar, 25120 KP, Pakistan.

PMID: 32504904
DOI: 10.1016/j.jcis.2020.05.093

Abstract

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 Pd⁰ 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^-1, 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^-1) and MB (0.626 min^-1) after regeneration presents good stability of 1.0PdAS in catalytic reactions.

Keywords: 2-D confined spaces; Catalytic reactions; Pd NPs; SBA-15; SSDS strategy.