MJCCA9 – 571 Received: December 22, 2010 Accepted: April 15, 2011 Macedonian Journal of Chemistry and Chemical Engineering. Vol. 30, No. 1, pp. 55–65 (2011) ISSN 1857–5552 UDC: 544.653:544.478 Original scientiic paper ELECTROCATALYTIC ACTIVITY OF HYPO–HYPER-d-ELECTROCATALYSTS (Me/TiO 2 /MWCNTs) BASED ON Co-Ru IN ALKALINE HYDROGEN ELECTROLYSER 1 * Perica Paunović 1 , Orce Popovski 2 , Dainka Stoevska Gogovska 1 , Elefteria Lefterova 3 , Evelina Slavcheva 3 , Aleksandar T. Dimitrov 1 1 Faculty of Technology and Metallurgy, Ss. Cyril and Methodius University Skopje Republic of Macedonia 2 Military Academy “General Mihailo Apostolski” Vasko Karangeleski bb, MK-1001 Skopje, Republic of Macedonia 3 Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl.11, 1113 Soia pericap@tmf.ukim.edu.mk This study is concerned with preparation and characterization of Co-Ru based hypo-hyper d- electrocatalysts aimed for water electrolysis. The composition of the studied electrocatalysts was: 10 % mixed metallic phase (Co : Ru = 1 : 1 wt., Co:Ru = 4 : 1 wt. and Co : Ru : Pt = 4 : 0.5 : 0.5), 18 % TiO 2 as a crystalline anatase deposited on activated multiwalled carbon nanotubes (MWCNTs). For comparison, corresponding electrocatalysts with pure hyper d-metallic phase (Co and Ru) were prepared. The structural characterization of the studied electrocatalysts was performed by means of XRD, SEM and FTIR analysis. The prepared hypo-hyper d-electrocatalysts were electrochemically studied by cyclic voltammetry and potentiodynamic method in the alkaline hydrogen electrolyser. The order of the catalytic activity for hydrogen evolution of studied electrocatalysts was the following: Ru > CoRuPt (4 : 0.5 : 0.5, wt.) > CoRu (1 : 1 wt.) > CoRu (4 : 1 wt.) > Co. The electrocatalyst with only 20 % precious metals (Pt and Ru) in the metallic phase (the rest being Co-metal) exhibited excellent performance approaching that of the electrocatalyst with 100 % precious metallic phase (Ru). Key words: hyper-hypo d-electrocatalysts; water electrolysis; hydrogen evolution; Co; Ru; anatase; MWCNTs ЕЛЕКТРОКАТАЛИТИЧКА АКТИВНОСТ НА ХИПО-ХИПЕР d-ЕЛЕКТРОКАТАЛИЗАТОРИ (Me/TiO 2 /MWCNTs) БАЗИРАНИ НА Co-Ru ВО АЛКАЛНИ ВОДОРОДНИ ЕЛЕКТРОЛИЗЕРИ Предмет на трудот е подготовка и карактеризација на хипо-хипер-d-електрокатализатори со намалено количество благородни метали, наменети за електролиза на водата. Испитуваните електрокатализатори содржат 10 % мешана метална фаза (Co : Ru = 1 : 1 мас., Co : Ru = 4 : 1 мас. and Co : Ru:Pt = 4 : 0,5 : 0,5 мас.), 18 % TiO 2 (анатаз), нанесени врз активирани повеќеѕидни јаглеродни 1 * Dedicated to Professor Svetomir Hadži Jordanov on the occasion of his 70 th birthday.