ABSTRACT
Biomass discharged from primary industries can be converted into methane by fermentation. This methane is used for generating electricity with solid oxide fuel cells (SOFCs). This methane fermentation provides H2S, which reduces the efficiency of SOFCs even at a level as low as a few parts per million. It has been experimentally reported that a nitrogen (N)-doped graphene-based material known as pyridinic N removes H2S via an oxidation reaction compared with another graphene-based material known as oxidized N. To understand this experimental result, we investigated H2S adsorption on pyridinic N and oxidized N by a density functional theory analysis and further examined the activation barrier of dissociation reactions. We found that the adsorption of H2S on pyridinic N is more stable than that on oxidized N. In addition, the H2S dissociation reaction occurs only on pyridinic N.
ABSTRACT
A Si nanoparticle paste has been studied to form a Si film on a substrate. Rapid thermal annealing (RTA) was conducted in order to recrystallize the Si paste which were prepared by a planetary ball milling grinding n-doped or p-doped Si chips. It was possible to minimize the oxidation during the melting process of Si nanoparticles with this RTA even at 1200 °C in 1 s. Lowering of the melting temperature appears to be due to the size effect and release of surface energy from the Si nanoparticles. RTA was conducted in an infrared furnace with temperatures varying from 1150 to 1300 °C. Si pn homo-junction structure was also fabricated by coating p-type followed by n-type Si pastes on a carbon substrate. Typical rectifying characteristics and slight photo-induced current was observed.
