Ni composite electrodes for hydrogen generation: Activation of Nb-based semiconductors

FRANCESCHINI, ESTEBAN A.; BENAVENTE LLORENTE, VICTORIA; LANTERNA, ANABEL E.

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2022

0360-3199

The hydrogen evolution reaction depends on the accumulation of electrons on the catalyticcenter to enable the two-electron processes involved in water reduction. This work reportson the modification of inexpensive nickel (Ni) composite electrodes with engineeredsemiconductor heterojunctions based on earth-abundant transition metals that show superiorhydrogen generation activity in the presence of a non-toxic electrolyte (K2CO3). Thisis, small amounts of cobalt (Co) or copper (Cu) oxides can improve the reactivity of compositeelectrodes formed by deposition of titanium (Ti) or niobium (Nb) semiconductorsonto Ni surfaces. In general, modified Nb-based semiconductors show better performanceand their enhanced activity can be understood in terms of modified surface potentialsupon formation of semiconductor-Ni heterojunctions. Photoelectrochemical activity canbe detected in the presence of Cu oxides, where hydrogen generation onset potential isreduced under UVeVis light irradiation. The study demonstrates that small composition