Enhancement of acidic OER performance through heterojunction interface coupling promoted by heteroatom doping

Ruthenium dioxide (RuO 2 ) faces the problem of poor stability due to the involvement of lattice oxygen (O L ) and over-oxidation of ruthenium when involved in the oxygen evolution reaction (OER) under acidic conditions. To address this problem, a Mn-RuO 2 /CeO 2 heterojunction catalyst was developed in this study for the enhancement of acidic OER. The Mn-RuO 2 /CeO 2 catalyst exhibited an overpotential of 227 mV at 10 mA·cm −2 , and the degradation of the OER performance was negligible after 300 h of continuous operation in 0.1 M HClO 4 . Experimental and theoretical calculations showed that Mn doping enhanced the interfacial interactions between the heterojunctions, resulting in a catalyst containing more high-valent Ru favorable for catalytic activity. This electronic state modulation optimized the d-band centre of Ru in the catalyst and lowered the reaction barriers, which led to an increase in the catalytic activity. In addition, the involvement of lattice oxygen and the dissolution of Ru during the OER process were suppressed to a certain extent due to the preferential oxidation of Mn and the transfer of electrons to RuO 2 via CeO 2 , thus enhancing the stability. This study provides a new perspective for balancing the activity and durability of RuO 2 -based catalysts.