Biomass waste rice husk derived silica supported palladium nanoparticles: an efficient catalyst for Suzuki–Miyaura and Heck–Mizoroki cross-coupling reactions

Investigation of different deposition methods for synthesized gold nanoparticles on a South African sugarcane leaves derived silica xerogel support

“…Both of these specific surface areas are lower than the specific surface area for silica without deposited gold nanoparticles which is 668 m 2 g −1 as expected due to the trend from the literature. Incorporating gold nanoparticles into the silica support slightly reduced the specific surface area by 7% for Si/Au-insitu, however, the specific surface area for Si/Au-added sample was significantly reduced by 52% due to the deposited agglomerated nanoparticles [7,41]. Ray et al [43] mentioned that the size and position of the deposited nanoparticles have an effect on the specific surface area of the loaded metal.…”

“…Gold nanoparticles have a relatively high surface area to volume ratio and in addition are reported to likely stick together to form clusters or larger particles [2,5]. When it comes to catalytic applications, directly using gold nanoparticles requires a tedious setup procedure to isolate the nanoparticles from the reaction medium or product due to their small sizes and as a result large amounts of waste becomes involved which leads to the manufacturing processes being expensive [7]. In addition, when gold nanoparticles are used directly in catalytic applications, recycling becomes impossible.…”

“…Deposition of gold nanoparticles on a solid support can efficiently reduce/prevent the nanoparticles from aggregating [2,5]. As opposed to homogenous catalysts, catalysts on a solid support are often preferred as they are easy to work with [7]. The solid support makes using gold nanoparticles more desirable because it makes it easy to separate from the reaction medium and also enables the option of recycling the catalyst.…”