Photoelectrochemical (PEC) water splitting for hydrogen production is a promising technology that uses sunlight and water to produce renewable hydrogen with oxygen as a by-product. In the expanding field of PEC hydrogen production, the use of standardized

Thermal-catalytic gas processing is integral to many current industrial processes. Ever-increasing demands on conversion and energy efficiencies are a strong driving force for the development of alternative approaches. Similarly, synthesis of several functional materials (such as nanowires and nanotubes) demands special processing conditions. Plasma catalysis provides such an alternative, where the catalytic process is complemented by the use of plasmas that activate the source gas. This combination is often observed to result in a synergy between plasma and catalyst. This Review introduces the current state-of-the-art in plasma catalysis, including numerous examples where plasma catalysis has demonstrated its benefits or shows future potential, including CO2 conversion, hydrocarbon reforming, synthesis of nanomaterials, ammonia production, and abatement of toxic waste gases. The underlying mechanisms governing these applications, as resulting from the interaction between the plasma and the catalyst, render the process highly complex, and little is known about the factors leading to the often-observed synergy. This Review critically examines the catalytic mechanisms relevant to each specific application.

In this report, we show for the first time that SnO2 nanowire based dye sensitized solar cells exhibit an open circuit voltage of 560 mV, which is 200 mV higher than that using SnO2 nanoparticle based cells. This is attributed to the more negative flat band potential of nanowires compared to the nanoparticles as determined by open circuit photo voltage measurements made at high light intensities. The nanowires were employed in hybrid structures consisting of highly interconnected SnO2 nanowire matrix coated with TiO2 nanoparticles, which showed an open circuit voltage of 720 mV and an efficiency of 4.1% compared to 2.1% obtained with pure SnO2 nanowire matrix. The electron transport time constants for SnO2 nanowire matrix were an order of magnitude lower and the recombination time constants are about 100 times higher than that of TiO2 nanoparticles. The higher efficiency observed for DSSCs based on hybrid structure is attributed to the band edge positions of SnO2 relative to that of TiO2 and faster electron transport in SnO2 nanowires.

In this study, vertical nanowire arrays of MoO(3-x) grown on metallic substrates with diameters of ~90 nm show high-capacity retention of ~630 mAhg(-1) for up to 20 cycles at 50 mAg(-1) current density. Particularly, they exhibit a capacity retention of ~500 mAhg(-1) in the voltage window of 0.7-0.1 V, much higher than the theoretical capacity of graphite. In addition, 10 nm Si-coated MoO(3-x) nanowire arrays have shown a capacity retention of ~780 mAhg(-1), indicating that hybrid materials are the next generation materials for lithium ion batteries.

Direct plasma oxidation of iron substrates results in the nucleation and growth of α‐Fe2O3 nanowire and nanobelt arrays (see image). The initial plasma heating in the early stages determines the nucleation density, and the growth of nanowires and nanobelts is a function of the temperature‐dependent diffusion of iron atoms and the plasma radical flux on the surface.