Ultrafast real-time optical imaging is an indispensable tool for studying dynamical events such as shockwaves, chemical dynamics in living cells, neural activity, laser surgery, and microfluidics. However, conventional CCDs and CMOS cameras are incapable of capturing fast dynamical processes with high sensitivity and temporal resolution. This is due in part to a technological limitation-it takes time to read out the data from the sensor array.

Interfacial electron transfer dynamics is important for environmental and catalytic reactions. Extensive ensemble-averaged studies have indicated inhomogeneous and complex dynamics of interfacial ET reaction. To characterize the inhomogeniety and the complex mechanism, we have applied femtosecond ultrafast spectroscopy, single-molecule photon stamping and Raman spectroscopy, and correlated AFM imaging to study the interfacial ET dynamics of dye molecules adsorbed at the surface of TiO2 nanoparticles.

Four seemingly simple transformations related to the chemistry of methane will be addressed from mechanistic and conceptual points of view, i.e.: 1) metal-mediated dehydrogenation to form metal-carbene complexes, 2) the hydrogen-atom abstraction step in the oxidative dimerization of methane, 3) the mechanisms of the CH4 -> CH3OH conversion, and 4) the initial bond scission as well as the rate-limiting step in the selective CH3OH -> CH2O oxidation.