Resonance Raman (RR) spectroscopy has several advantages over the normal Raman spectroscopy (RS) widely used for in situ characterization of solid catalysts and catalytic reactions. Compared with RS, RR can provide much higher sensitivity and selectivity in detecting catalytically-significant surface metal oxides. RR can potentially give useful information on the nature of excited states relevant to photocatalysis and on the anharmonic potential of the ground state. In this critical review a detailed discussion is presented on several types of RR experimental systems, three distinct sources of so-called Raman (fluorescence) background, detection limits for RR compared to other techniques (EXAFS, PM-IRAS, SFG), and three well-known methods to assign UV-vis absorption bands and a band-specific unified method that is derived mainly from RR results. In addition, the virtues and challenges of surface-enhanced Raman spectroscopy (SERS) are discussed for detecting molecular adsorbates at catalytically relevant interfaces. Tip-enhanced Raman spectroscopy (TERS), which is a combination of SERS and near-field scanning probe microscopy and has the capability of probing molecular adsorbates at specific catalytic sites with an enormous surface sensitivity and nanometre spatial resolution, is also reviewed (300 references).

Unsupported catalyst for green chemistry: The aerobic oxidation and coupling of primary alcohols (methanol, ethanol, n‐butanol) to give the corresponding aldehydes and esters at temperatures below 100 °C is facilitated by unsupported nanoporous gold catalysts. The experimental conditions employed allow a close comparison to model experiments and open the door to a molecular‐level understanding of the reaction.

Highly uniform submonolayer to multilayer thin films of titanium dioxide supported on high surface area silica gel have been synthesized by atomic layer deposition (ALD) using titanium tetrachloride (TiCl 4) and titanium isopropoxide (TTIP) as metal precursors. The deposition rate of titania films from TiCl 4 was found to be stable in the 150-300°C temperature range, which is slightly higher than that from TTIP at 150°C. UV-visible diffuse reflectance spectroscopy (DRS) shows that the coordination geometry of Ti cations depends on the number of ALD cycles and the precursor but is essentially independent of deposition temperature. Using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and visible Raman spectroscopy with pyridine as a probe molecule, we found all of the titania films studied to exhibit Lewis acidity but only films containing chloride or carbonyl impurities possessed Brønsted acid sites. Additionally, three new pronounced bands in the Raman spectra, ν 6b (638 cm-1), ν 9a (1200 cm-1), and ν 2 (3103 cm-1), provide strong spectroscopic evidence for Brønsted acid sites on the surface.

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