  Hydrogen is largely produced via natural gas reforming or electrochemical
water-splitting, leaving organic solid feedstocks under-utilized. Plasma
technology powered by renewable electricity can lead to the sustainable
upcycling of plastic waste and production of green hydrogen. In this work,
low-temperature atmospheric pressure plasma reactors based on transferred arc
(transarc) and gliding arc (glidarc) discharges are designed, built, and
characterized to produce hydrogen from low-density polyethylene (LDPE) as a
model plastic waste. Experimental results show that hydrogen production rate
and efficiency increase monotonically with increasing voltage level in both
reactors, with the maximum hydrogen production of 0.33 and 0.42 mmol/g LDPE for
transarc and glidarc reactors, respectively. For the transarc reactor, smaller
electrode-feedstock spacing favors greater hydrogen production, whereas, for
the glidarc reactor, greater hydrogen production is obtained at intermediate
flow rates. The hydrogen production from LDPE is comparable despite the
markedly different modes of operation between the two reactors.
