Claudia Longo1,Nadia Macedo1,Jessica Alvim1,Leonardo Soares1,Márcio Sangali1,Rubens Caram Jr1,Luelc Costa1,Miguel Galante1
University of Campinas1
Claudia Longo1,Nadia Macedo1,Jessica Alvim1,Leonardo Soares1,Márcio Sangali1,Rubens Caram Jr1,Luelc Costa1,Miguel Galante1
University of Campinas1
Semiconductor oxides have been used as photocatalysts for conversion of solar energy in different applications of technological interest. Compared to binary oxides, the multinary oxides can exhibit improved sunlight harvesting; also, the conduction and valence band edges can be modulated, that can enhance the selectivity for some photoelectrochemical (PEC) reactions. Recently, our research group used the arc-melting of Cu<sub>2</sub>O and WO<sub>3</sub> precursors for synthesizing Cu<sub>2</sub>WO<sub>4</sub>, a p-type semiconductor. Ongoing studies revealed that Cu<sub>2</sub>WO<sub>4</sub> particles immobilized on gas diffusion electrodes produced ethanol from PEC CO<sub>2</sub> reduction reaction (PEC-CO<sub>2</sub>RR). Electrodes prepared with particles of the composite containing CuFeO<sub>2 </sub>and copper oxides, obtained by arc-synthesis from of Cu<sub>2</sub>O and Fe<sub>2</sub>O<sub>3</sub> precursors, also behave as p-type semiconductor electrodes and have been evaluated as photocathodes for PEC-CO<sub>2</sub>RR and in-situ H<sub>2</sub>O<sub>2</sub> production from PEC O<sub>2</sub> reduction reaction. On the other hand, electrodes containing ilmenite (FeTiO<sub>3</sub>) particles synthesized by arc-melting of TiO<sub>2</sub> and Fe<sub>2</sub>O<sub>3</sub> precursors behave as n-type semiconductor; ongoing studies revealed that ilmenite electrodes exhibited high efficiency and excellent long-term stability for application as photoanodes for PEC oxygen evolution reaction (PEC-OER). PEC properties of n-type semiconductor electrodes were also observed for the multiphasic α-AgVO<sub>3</sub>/Fe<sub>2</sub>O<sub>3</sub>/Ag synthesized by arc-melting. Scanning electron microscopy and energy dispersive spectroscopy revealed that this composite consisted of Ag nanoparticles decorating micrometric Fe<sub>2</sub>O<sub>3</sub> and nanostructures of the metastable α-AgVO<sub>3</sub>. The performance of such photoanode for PEC OER and for removal of contaminants of emerging concern from water is under investigation. These results revealed that arc-melting can be used as a time-efficient methodology for synthesizing multinary complex oxides for application in PEC reactors for water decontamination and for solar fuels production from CO<sub>2</sub>RR.