Photoelectrochemical water splitting for H2 generation is a desirable energy alternative to fossil fuels yet often requires expensive and rare metals, such as Pt, as the counter electrode (CE). Ideally, an earth abundant, inexpensive CE which catalyzes the oxygen evolution reaction (OER) would be paired with a working electrode (WE) capable of catalyzing the hydrogen evolution reaction (HER) to facilitate water splitting. We previously reported on a cysteine (cys)-CdS/Pb0.33V2O5 heterostructure WE which catalyzed the HER, along with oxidation of a sacrificial electron donor, with a Faradaic efficiency of 92 ± 6%. We have combined these heterostructure-functionalized WEs with CEs functionalized with cobalt phosphate (CoPi), a reported OER-catalyzing material. This presentation will focus on recent work involving: (1) optimization of CoPi synthesis via cyclic voltammetry and (2) demonstrating that CoPi is a viable alternative for Pt mesh through characterization of photocurrent production and photogenerated products. We hypothesized that photoelectrochemical cells incorporating the CoPi-functionalized CEs would generate comparable water-splitting photocurrents as cells utilizing Pt mesh CEs, and that H2 and O2 would be generated during prolonged illumination. Experimental results revealed that the photocurrent produced with CoPi generally exceed those produced with Pt mesh. Photoelectrochemical cells the combination of a CoPi CE and cys-CdS/Pb0.33V2O5 WE also generated H2 with a Faradaic efficiency of around 40%, consistent with a mechanism involving photoelectrochemical water splitting. These results reveal that the CoPi CE paired with cys-CdS/Pb0.33V2O5 WE is a viable combination for accomplishing photoelectrochemical water splitting with earth abundant and inexpensive materials.

Photoelectrochemical hydrogen generation with cys-CdS/β-Pb0.33V2O5 photocathodes and cobalt phosphate anodes for efficient water splitting

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