TheBosch reactionis a catalyticchemical reactionbetweencarbon dioxide(CO2) andhydrogen(H2) that produces elementalcarbon(C,graphite),water,and a 10% return of investedheat.CO2is usually reduced by H2to carbon in presence of acatalyst(e.g.iron(Fe)) and requires a temperature level of 530–730 °C (986–1,346 °F).[1][2]
The overall reaction is as follows:
The above reaction is actually the result of two reactions. The first reaction, thereverse water gas shift reaction,is a fast one:
- CO2+ H2→ CO + H2O
The second reaction is therate determining step:
- CO + H2→ C + H2O
The overall reaction produces 2.3×103joulesfor every gram of carbon dioxide reacted at 650 °C. Reaction temperatures are in the range of 450 to 600 °C.
The reaction can be accelerated in the presence of aniron,cobaltornickelcatalyst.Rutheniumalso serves to speed up the reaction.
Applications
editTogether with theSabatier reaction,the Bosch reaction is studied as a way to remove carbon dioxide and to generate clean water aboard aspace station.[3]
The reaction is also used to produce graphite forradiocarbon datingwithAccelerator Mass Spectrometry.
The Bosch reaction is being investigated for use in maintaining space station life support. Though the Bosch reaction would present a completely closed hydrogen andoxygen cyclewhich only produces atomic carbon as waste, difficulties in maintaining its higher required temperature and properly handling carbon deposits mean that significantly more research will be required before a Bosch reactor can become a reality. One problem is that the production of elemental carbon tends to foul the catalyst's surface, which is detrimental to the reaction's efficiency.
Notes
edit- ^Messerschmid, Ernst and Reinhold Bertrand. Space Stations. Springer. 1999.
- ^Porosoff, Marc D.; Yan, Binhang; Chen, Jingguang G. (2016)."Catalytic reduction of CO 2 by H 2 for synthesis of CO, methanol and hydrocarbons: challenges and opportunities".Energy & Environmental Science.9(1): 62–73.doi:10.1039/C5EE02657A.ISSN1754-5692.OSTI1335402.
- ^Methods of water productionArchivedMay 29, 2005, at theWayback Machine