The pseudo-capacitance of hydrous RuO2 accompanied by mass changes

Abstract

Pseudocapacive reaction of ruthenium oxide was investigated by cyclic voltammetry (CV) measurements combined with electrochemical quartz-crystal nanobalance. RuO2 was synthesized by one-pot microwave assisted hydrothermal method. CV measurements were conducted in H2SO4 and Na2SO4 solutions. The ruthenium oxide electrode as a working electrode was prepared by drop casting the water suspension of RuO2 on Au covered quartz electrode. Beside influence of different electrolyte, the effect of thermal treatment of RuO2 was also investigated since pseudocapacitive behaviour of RuO2 strongly depends on its hydrous form. The obtained results were compared to those of commercial RuO2. The results indicate that during the redox reaction of RuO2, various types of charge occur simultaneously. The mass loss or mass gain depends on the specific potential applied and the electrolyte employed.

Pseudokapacitivna reakcija rutenijum oksida ispitivana je metodom ciklične voltametrije (CV) u kombinaciji sa primenom elektrohemijske kvarc-kristalne nanovage. RuO2 je sintetizovan jednostepenom hidrotermalnom metodom, pomoću mikrotalasne tehnike. CV merenja su sprovedena u rastvorima H2SO4 i Na2SO4. Elektroda od rutenijum oksida kao radna elektroda je pripremljena nakapavanjem vodene suspenzije RuO2 na zlatom prekrivenu kvarcnu elektrodu. Pored uticaja različitih elektrolita, istražen je i efekat termičkog tetmana RuO2 jer seudokapacitivno ponašanje RuO2 u velikoj meri zavisi od njegovog hidratisanog oblika. Dobijeni rezultati su upoređeni sa rezultatima ispitivanja komercijalnog RuO2. Rezultati pokazuju da se tokom redoks reakcije RuO2 istovremeno javljaju različite vrste naelektrisanja. Gubitak mase ili povećanje mase zavisi od primenjenog potencijala i upotrebljenog elektrolita.