I've taken the liberty of reproducing a CHMED-L post from Eric Scerri about hydrogen's position in the periodic table.
The position of hydrogen in the periodic system is a much debated topic. Authors have suggested groups I, VII and even IV over the years. Others opt from removing H from the main body of the table, along with He. The official journal of IUPAC, called Chemistry International, has been running some articles and comments on this issue.
The Science Blog reports that researchers at Penn State in the USA are developing self-cleaning titania nanotube hydrogen sensors. The hydrogen sensors are titania nanotubes coated with a discontinuous layer of palladium. Hydrogen sensors are widely used in the chemical, petroleum and semiconductor industries. They are also used as diagnostic tools to monitor certain types of bacterial infections.
"The photocatalytic properties of titania nanotubes are so large - a factor of 100 times greater than any other form of titania - that sensor contaminants are efficiently removed with exposure to ultraviolet light, so that the sensors effectively recover or retain their original hydrogen sensitivity in real world application"
"By doping the titania nanotubes with trace amounts of different metals such as tin, gold, silver, copper, niobium and others, a wide variety of chemical sensors can be made. This doping does not alter the photocatalytic properties of the titania nanotubes" says Dr. Craig A. Grimes, associate professor of Electrical Engineering and Materials Science and Engineering.1
- 1. A room-temperature titania-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination,
, Journal of Materials Research, 02/2004, Volume 19, Issue 2, p.628?634, (2004)