Editing Electrolysis (section)

===Carbon/hydrocarbon assisted water electrolysis===
{{main|Hydrogen production}}
Recently, to reduce the energy input, the utilization of carbon ([[coal]]), [[Alcohol (chemistry)|alcohol]]s (hydrocarbon solution), and organic solution ([[glycerol]], formic acid, [[ethylene glycol]], etc.) with co-electrolysis of water has been proposed as a viable option.<ref>{{cite journal|doi=10.1016/j.apenergy.2018.09.125|title=A comprehensive review of carbon and hydrocarbon assisted water electrolysis for hydrogen production|journal=Applied Energy|volume=231|pages=502–533|year=2018|last1=Ju|first1=Hyungkuk| last2=Badwal|first2=Sukhvinder|last3=Giddey|first3=Sarbjit|bibcode=2018ApEn..231..502J |s2cid=117669840 }}</ref><ref>{{cite journal|doi=10.1016/j.electacta.2016.07.062|title=Electro-catalytic conversion of ethanol in solid electrolyte cells for distributed hydrogen generation|journal=Electrochimica Acta|volume=212|pages=744–757|year=2016|last1=Ju|first1=Hyungkuk|last2=Giddey|first2=Sarbjit|last3=Badwal|first3=Sukhvinder P.S.|last4=Mulder|first4=Roger J.}}</ref> The carbon/hydrocarbon assisted water electrolysis (so-called CAWE) process for hydrogen generation would perform this operation in a single [[electrochemical]] reactor. This system energy balance can be required only around 40% electric input with 60% coming from the chemical energy of carbon or hydrocarbon.<ref>{{cite journal|doi=10.1016/j.ijhydene.2014.11.033|title=Low emission hydrogen generation through carbon assisted electrolysis|journal=International Journal of Hydrogen Energy|volume=40|pages=70–74|year=2015|last1=Giddey|first1=S.|last2=Kulkarni|first2=A.|last3=Badwal|first3=S.P.S.|issue=1 |bibcode=2015IJHE...40...70G }}</ref> This process utilizes solid coal/carbon particles or powder as fuels dispersed in acid/alkaline electrolyte in the form of slurry and the carbon contained source co-assist in the electrolysis process as following theoretical overall reactions:<ref>{{cite journal|doi=10.1016/j.ijhydene.2018.03.195|title=Role of iron species as mediator in a PEM based carbon-water co-electrolysis for cost-effective hydrogen production|journal=International Journal of Hydrogen Energy|volume=43|issue=19|pages=9144–9152|year=2018|last1=Ju|first1=Hyungkuk|last2=Giddey|first2=Sarbjit|last3=Badwal|first3=Sukhvinder P.S.|bibcode=2018IJHE...43.9144J }}
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:Carbon/Coal slurry (C + 2H<sub>2</sub>O) → CO<sub>2</sub> + 2H<sub>2</sub> {{pad|2em}} ''E''′ = 0.21&nbsp;V (reversible voltage) / ''E''′ = 0.46&nbsp;V (thermo-neutral voltage)

or

:Carbon/Coal slurry (C + H<sub>2</sub>O) → CO + H<sub>2</sub> {{pad|2em}} ''E''′ = 0.52&nbsp;V (reversible voltage) / ''E''′ = 0.91&nbsp;V (thermo-neutral voltage)

Thus, this CAWE approach is that the actual cell overpotential can be significantly reduced to below 1.0&nbsp;V as compared to 1.5&nbsp;V for conventional water electrolysis.