Photoelectrochemistry

Photoelectrochemistry studies how light-driven charge separation at a semiconductor-electrolyte interface can be harnessed to drive useful redox chemistry — most prominently solar water splitting (the hydrogen and oxygen evolution reactions), CO2 reduction to fuels and feedstocks, nitrogen reduction, and pollutant degradation. The field sits between heterogeneous photocatalysis and conventional electrochemistry: a photoelectrode absorbs photons, generates electron-hole pairs, and either oxidizes or reduces a species in solution while the complementary half-reaction proceeds at a counter electrode.

The standard experimental toolkit is a three-electrode photoelectrochemical (PEC) cell illuminated through an optical window, with the working electrode under bias from a potentiostat and the cell mounted on the optical axis of a calibrated solar simulator (typically AM 1.5G) or a tunable monochromated source. Core measurements include linear sweep voltammetry under chopped light, open-circuit photopotential, electrochemical impedance spectroscopy with Mott-Schottky analysis to extract flat-band potential and donor density, and incident-photon-to-current-efficiency (IPCE) spectra for wavelength-resolved quantum yield.

Material families researched in this space include n-type metal-oxide photoanodes (TiO2, hematite Fe2O3, BiVO4, WO3), p-type photocathodes (Cu2O, CuBi2O4, silicon, III-V semiconductors), and increasingly tandem and Z-scheme architectures that pair complementary absorbers. These are routinely paired with co-catalysts (NiOOH, FeOOH, CoPi for OER; Pt, MoS2, NiMo for HER), surface passivation layers, and protective overlayers deposited by ALD.

Supporting materials and laboratory equipment used in photoelectrochemical research — substrates, electrolytes, reference and counter electrodes, cells, and instrumentation — are distributed across the rest of the catalog rather than collected here. If you are sourcing components for a PEC build, browse substrates, reference electrodes, and the broader energy conversion section.