Sungas Instead of Syngas: Efficient Coproduction of CO and H₂ with a Single Beam of Sunlight

Abstract

The electrolytic coproduction of CO and H2 is achieved from air, water, and a single beam of sunlight rather than from fossil fuels. H2 and CO cosynthesis is driven by a single concentrator photovoltaic to simultaneously drive molten hydroxide and molten carbonate electrolyses. The carbon neutral process captures carbon without the need for the preconcentration of atmospheric carbon dioxide.

Thermodynamic assessment of CO2 to carbon nanofiber transformation for carbon sequestration in a combined cycle gas or a coal power plant

“…Higher efficiency is achieved by using the full spectrum of sunlight. As we have previously demonstrated, visible sunlight provides efficient electrical power and the thermal sunlight provides supplemental heating of STEP electrolyses [44][45][46]54,55]. For example, conventional photovoltaics use super-bandgap (visible) radiation, and cannot use sub-band (thermal energy) as it is not sufficient to drive electron/hole separation.…”

Sustainable Electrochemical Synthesis of Large Grain- or Catalyst-Sized Iron

“…The electrolysis potential is measured as the voltage between the anode and the cathode at constant current. We have previously reported on STEP cathode or oxygen anode potentials in a variety of molten carbonates [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] During electrolysis, the iron product accumulates at the cathode, which is subsequently removed and cooled. Details of STEP electrolysis are provided in references [5][6][7][8].…”

“…Fundamental, electrochemical, and impurity effects on STEP iron have been investigated [8], and the general effects of alkali earth and hydroxide on STEP processes in molten carbonates have been reported [14][15][16][17][18][19][20]. The fundamental increase in solar electrolysis efficiency with the use of solar thermal has been analyzed for CO 2 and H 2 O splitting theoretically [10][11][12] and experimentally [13][14][15] and the fundamental endogenic decrease in electrochemical potential with the increasing temperature demonstrated for a number of STEP processes [10][11][12][13][14][15][16][17][18][19][20]. The requisite solar thermal heating for any given process will depend on the current density, which controls the overpotential and the net difference between the thermoneutral potential and the applied electrolysis potential.…”

“…The general solar thermal electrochemical process (STEP) of sunlight to decrease (endogenic) electrolysis potentials leads to high solar energy conversion efficiencies [6][7][8][9][10][11]. A variety of other STEP electrolyses have been demonstrated to decrease CO 2 including the production of cement, ammonia, fuels, and carbon for the direct removal of atmospheric or smokestack carbon dioxide [10][11][12][13][14][15][16][17][18][19][20]. Fundamental, electrochemical, and impurity effects on STEP iron have been investigated [8], and the general effects of alkali earth and hydroxide on STEP processes in molten carbonates have been reported [14][15][16][17][18][19][20].…”

“…A variety of other STEP electrolyses have been demonstrated to decrease CO 2 including the production of cement, ammonia, fuels, and carbon for the direct removal of atmospheric or smokestack carbon dioxide [10][11][12][13][14][15][16][17][18][19][20]. Fundamental, electrochemical, and impurity effects on STEP iron have been investigated [8], and the general effects of alkali earth and hydroxide on STEP processes in molten carbonates have been reported [14][15][16][17][18][19][20]. The fundamental increase in solar electrolysis efficiency with the use of solar thermal has been analyzed for CO 2 and H 2 O splitting theoretically [10][11][12] and experimentally [13][14][15] and the fundamental endogenic decrease in electrochemical potential with the increasing temperature demonstrated for a number of STEP processes [10][11][12][13][14][15][16][17][18][19][20].…”