TALH in itself is not photocatalytically active and is therefore subjected to a calcination step at 450°C for 30 mins to convert it into a photocatalytically active crystalline TiO2 phase in the SPs (as confirmed by XRD in Figure ). The UV-Vis and DRS of all the synthesized materials before and after calcination are represented in Figure a-b. Figure represents the UV-Vis spectra of Au-TiO2 SP before calcination. It can be observed that the clear plasmon band between 500-550 nm becomes less pronounced, and the absorbance is extended across the entire visible range when moving from Au@CloseSmall to Au@CloseLarge. The extended absorption cross-section of larger Au@CloseLarge SPs is in accordance with previous studies. For the Au@DistantSmall SPs, the plasmon band reemerges. After calcination at 450°C, the DRS spectra are quite similar to those before calcination with minor differences as observed in Figure . One of the main differences is a clearer and more pronounced absorption onset from 380 nm and below, which can be attributed to the bandgap of TiO2. An extended broadening is observed around 450 nm which can be attributed to the supporting silicon wafer.