The utilization of photoelectrochemical (PEC) cell for visible-light water oxidation has been considered as one of the most promising ways in developing a sustainable solar-to-fuel energy system. Nevertheless, most of the currently developed PECs still suffer from low energy conversion efficiency due to the fast electron-hole recombination. Here, we demonstrated that the exposure of high energy crystal facet and co-deposition of Rumbpy ([Ru(bipyP)(dmb)2]2+; bipyP: 2,2’-bipyridine-4,4’-diphosphoric acid, dmb: 4,4’-dimethyl-2,2’-bipyridine) and cobalt(II) meso-tetra(4-carboxyphenil)porphyrin (CoTCPP) was able to significantly enhance the PEC performance of titania-coated BiVO4 photoanode in water photooxidation. Based on the result, the exposure of TiO2’s (001) facet and co-deposition of Rumbpy and CoTCPP successfully increased photocurrent density of the photoanode and reduced the water oxidation onset potential under the illumination of 100 mW/cm2 light source at pH 7 with near-perfect Faradic efficiency of 97%. Both electrochemical and PEC investigations revealed that cascade hole transport from BiVO4 to Rumbpy and subsequently to CoTCPP was responsible for improving water oxidation kinetic. Additionally, this study finds that the exposure of TiO2’s (001) facet was also responsible for a more efficient hole transfer, leading to a further increase in PEC performance of the photoanode.

Enhancing water photooxidation of BiVO4 by using (001)-exposed TiO2 and co-deposition of ruthenium dye and cobalt co-catalyst

ACS Spring 2022

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