Photoelectrochemical water splitting

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.11 × C.19 · Incident radiation flux × Photoelectrochemicalfamily: Photoelectrochemical

Measured or reported performance

Summary figures only; no datum-level record yet. Each figure below is a reviewed summary, not a single measurement.

Recorded variants on this exact route

A variant is a narrower recorded architecture with the same claim sequence — its own evidence, data and bounds, evaluated beside the route (pass 46). Its figures and its architecture-specific limits belong to it, never to the generic pathway above.

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

• Nernst / Gibbs free-energy bound · resource-bound · listed, never decisive
  W_electrical ≤ −ΔG = nFE_cell
• Landsberg limit · formula-bound · hard, applies to this route
  η ≤ 1 − (4/3)(T_c/T_s) + (1/3)(T_c/T_s)⁴ for conversion of blackbody radiation at T_s with a sink at T_c; 93.3 % at 6000 K / 300 K
• PEC water-splitting ideal limit, single junction · upper-bound · hard, applies to this route
  η_STH ≤ 30.6 % for a single-junction photoelectrochemical water-splitting device under AM1.5G in the ideal case (E_g 1.59 eV at the maximum)
• PEC water-splitting ideal limit, dual junction · upper-bound · hard, applies to this route
  η_STH ≤ 40.0 % for a dual-junction photoelectrochemical water-splitting device under AM1.5G in the ideal case (E_g 0.52 / 1.40 eV at the maximum); a third junction adds nothing (the ideal triple-junction maximum is 28.3 %)
• PEC water-splitting realistic limiting efficiency, high-performance materials (Fountaine Real1) · benchmark · listed, never decisive
  η_max 15.1 % single junction (E_g 2.05 eV) and 28.3 % dual junction (1.59 / 0.92 eV) for absorption fraction 0.9, external radiative efficiency 0.03, catalytic exchange current densities {1, 10⁻³} mA cm⁻² (cathodic, anodic), series resistance 0, shunt resistance infinite
• PEC water-splitting realistic limiting efficiency, Earth-abundant materials (Fountaine Real2) · benchmark · listed, never decisive
  η_max 5.4 % single junction (E_g 2.53 eV) and 16.2 % dual junction (1.93 / 1.38 eV) for absorption fraction 0.9, external radiative efficiency 10⁻⁶, catalytic exchange current densities {1, 10⁻⁵} mA cm⁻², normalised series resistivity 0.1 and shunt resistivity 10

Steps

1. 01
   Incident radiation flux —drives→ Photoelectrochemical effectestablishedclaim record

   radiative → chemical · loss to thermal

   • a semiconductor photoelectrode whose band edges straddle the water redox potentials, in an electrolyte, under illumination

   aqueous medium required · semiconductor required · illumination required

   refs [1] [2]
2. 02
   Photoelectrochemical effect —converts into→ Chemical fuelestablishedclaim record

   chemical → chemical · loss to thermal

   • hydrogen evolved at the counter-electrode

   refs [1] [2]

Evidence for the complete composition · 2

1. [1]
   A. Fujishima, K. Honda. Electrochemical photolysis of water at a semiconductor electrode (1972)

   Nature 238, 37–38 · doi:10.1038/238037a0 · crossref ✓ 2026-09-19 · record
2. [3]
   W.-H. Cheng et al.. Monolithic Photoelectrochemical Device for Direct Water Splitting with 19% Efficiency (2018)

   ACS Energy Letters 3, 1795–1800 · doi:10.1021/acsenergylett.8b00920 · record

Evidence for the constituent relations · 2

1. [1]
   A. Fujishima, K. Honda. Electrochemical photolysis of water at a semiconductor electrode (1972)

   Nature 238, 37–38 · doi:10.1038/238037a0 · crossref ✓ 2026-09-19 · record
2. [2]
   M. Grätzel. Photoelectrochemical cells (2001)

   Nature 414, 338–344 · doi:10.1038/35104607 · crossref ✓ 2026-09-19 · record