{{About|the photoelectrochemical system|related systems|Electrolysis of water|and|Photocatalytic water splitting}}
'''Photoelectrolysis of water''', also known as '''photoelectrochemical [[water splitting]]''', occurs in a [[photoelectrochemical cell]] when [[light]] is used as the energy source for the [[electrolysis]] of water, producing [[dihydrogen]] which can be used as a fuel. This process is one route to a "[[hydrogen economy]]", in which hydrogen fuel is produced efficiently and inexpensively from natural sources without using [[fossil fuel]]s.<ref>{{Cite journal | doi = 10.1063/1.1878333 | title = The Hydrogen Economy | year = 2004 | last1 = Crabtree | first1 = G. W. |author-link1=George Crabtree| last2 = Dresselhaus | first2 = M. S. |author-link2=Mildred Dresselhaus| last3 = Buchanan | first3 = M. V. | journal = Physics Today | volume = 57 | pages = 39|bibcode = 2004PhT....57l..39C }}</ref><ref>{{Cite journal |last=Ropero-Vega |first=J.L. |last2=Pedraza-Avella |first2=J.A. |last3=Niño-Gómez |first3=M.E. |date=September 2015 |title=Hydrogen production by photoelectrolysis of aqueous solutions of phenol using mixed oxide semiconductor films of Bi–Nb–M–O (M=Al, Fe, Ga, In) as photoanodes |url=https://linkinghub.elsevier.com/retrieve/pii/S0920586114007512 |journal=Catalysis Today |language=en |volume=252 |pages=150–156 |doi=10.1016/j.cattod.2014.11.007|url-access=subscription }}</ref> In contrast, [[steam reforming]] usually or always uses a fossil fuel to obtain hydrogen. Photoelectrolysis is sometimes known colloquially as the ''hydrogen [[Holy Grail#Casual metaphor|holy grail]]'' for its potential to yield a viable alternative to [[petroleum]] as a source of [[energy]]; such an energy source would supposedly come without the [[sociopolitical]]ly undesirable effects of extracting and using petroleum.
Some researchers have practiced photoelectrolysis by means of a [[Nanoscopic scale|nanoscale]] process. Nanoscale photoelectrolysis of water could someday reach greater efficiency than that of "traditional" photoelectrolysis. Semiconductors with bandgaps smaller than 1.7 [[electronvolt|eV]] would ostensibly be required{{citation needed|date=June 2017}} for efficient nanoscale photoelectrolysis using light from the [[Sun]].
Devices based on [[hydrogenase]] have also been investigated.<ref> {{cite book |first1=Alison |last1= Parkin |editor=Peter M.H. Kroneck and Martha E. Sosa Torres |title=The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment |series=Metal Ions in Life Sciences |volume=14 |year=2014 |publisher=Springer |chapter=Chapter 5. ''Understanding and Harnessing Hydrogenases, Biological Dihydrogen Catalysts'' |pages=99–124 |doi=10.1007/978-94-017-9269-1_5 }} </ref>
== See also ==
* [[Artificial photosynthesis]] * [[Electrochemiluminescence]] * [[Photoelectrochemical reduction of CO2|Photoelectrochemical reduction of CO<sub>2</sub>]] * [[Photoelectrochemistry]] * [[Electrolysis of water]] * [[Photocatalytic water splitting]]
== References == <references/>
[[Category:Hydrogen production]] [[Category:Photoelectrochemistry]]
[[ja:電気化学#光電気化学]]