Partner: Craig Robertson

University of Warwick (GB)

Recent publications
1.Akay Ö., Poon J., Robertson C., Abdi F., Cuenya B.R., Giersig M., Brinkert K., Releasing the Bubbles: Nanotopographical Electrocatalyst Design for Efficient Photoelectrochemical Hydrogen Production in Microgravity Environment, Advanced science, ISSN: 2198-3844, DOI: 10.1002/advs.202105380, No.2105380, pp.1-11, 2021
Abstract:

Photoelectrochemical devices integrate the processes of light absorption, charge separation, and catalysis for chemical synthesis. The monolithic design is interesting for space applications, where weight and volume constraints predominate. Hindered gas bubble desorption and the lack of macroconvection processes in reduced gravitation, however, limit its application in space. Physico-chemical modifications of the electrode surface are required to induce gas bubble desorption and ensure continuous device operation. A detailed investigation of the electrocatalyst nanostructure design for light-assisted hydrogen production in microgravity environment is described. p-InP coated with a rhodium (Rh) electrocatalyst layer fabricated by shadow nanosphere lithography is used as a model device. Rh is deposited via physical vapor deposition (PVD) or photoelectrodeposition through a mask of polystyrene (PS) particles. It is observed that the PS sphere size and electrocatalyst deposition technique alter the electrode surface wettability significantly, controlling hydrogen gas bubble detachment and photocurrent–voltage characteristics. The highest, most stable current density of 37.8 mA cm−2 is achieved by depositing Rh via PVD through 784 nm sized PS particles. The increased hydrophilicity of the photoelectrode results in small gas bubble contact angles and weak frictional forces at the solid–gas interface which cause enhanced gas bubble detachment and enhanced device efficiency.

Keywords:

electrocatalyst nanotopography, hydrogen evolution, microgravity, photoelectrocatalysis, (photo-)electrochemical gas bubble evolution, shadow nanosphere lithography

Affiliations:
Akay Ö.-Free University of Berlin (DE)
Poon J.-Fritz Haber Institute of the Max Planck Society (DE)
Robertson C.-University of Warwick (GB)
Abdi F.-Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie (DE)
Cuenya B.R.-Fritz Haber Institute of the Max Planck Society (DE)
Giersig M.-IPPT PAN
Brinkert K.-University of Warwick (GB)