Cubic Gold Nanorattles with a Solid Octahedral Core and Porous Shell as Efficient Catalyst: Immobilization and Kinetic Analysis

Plasmonic nanostructures having porous morphology have attracted a great deal of attention in catalysis because of high surface-to-volume ratio, better surface reactivity, and availability of various structural features. We report the synthesis, immobilization, and kinetic analysis of cubic gold nanorattles (AuNRTs) comprising a solid octahedral core surrounded by a thin porous cube-shaped gold shell toward the reduction of p-nitrophenol (an environmental pollutant) and degradation of organic dyes (Congo red and methylene blue) as model systems. Kinetic investigation of our study showed that AuNRTs are an excellent catalyst compared with solid silver nanocube containing an octahedral gold core (AuOCT@Ag) and gold nanospheres (AuNSs), which could be attributed to the porous structure of nanorattles with three available surfaces: outer and inner walls and inner core for catalysis. A detailed analysis of the different kinetic and thermodynamic parameters revealed that AuNRTs have the highest reaction rate constant, lowest activation energy, pre-exponential factors, and entropy of activation. Furthermore, the immobilized AuNRTs into calcium alginate beads could retain their catalytic efficiency up to 15 cycles, demonstrating high stability and reproducibility. The present system shows the ability to efficiently degrade pollutants and thus can be used for potential environmental remediation application.