In this study, commercially available $\gamma$-type manganese dioxide, namely electrolytic manganese dioxide (EMD), was transformed to a bifunctional catalyst that exhibits activity not only for the oxygen reduction reaction (ORR) but also for the oxygen evolution reaction (OER), by the doping of cobalt into EMD without changing its framework structure. The use of EMD, which has long been proven in the primary battery industry, would be advantageous in terms of manufacturing, supply, and quality control. The process involves a simple wet treatment of EMD in the presence of N₂H₄ and Co²⁺. EMD is intrinsically active for the ORR, more than chemically-synthesized MnO₂, but inactive for the inverse reaction, the OER. Here, the extremely high mass activity of a small amount of Co that was introduced into the framework of $\gamma$-MnO₂ boosted its OER activity, while did not offset the ORR activity. As a result, the overpotential at 10 mA cm⁻² in the OER was measured to be 440 mV, while that at −1 mA cm⁻² in the ORR was 447 mV. Their sum (η_OER+η_ORR) of 887 mV was much smaller than that (1040 mV) of pristine EMD and differed from that of Pt/C by only 26 mV.

在本研究中，可商购 $\gamma$型二氧化锰，即电解二氧化锰（EMD），通过将钴掺杂到EMD中，转化为不仅对氧还原反应（ORR）而且对氧释放反应（OER）都具有活性的双功能催化剂无需更改其框架结构。EMD的使用已在原电池行业中得到长期验证，在制造，供应和质量控制方面将是有利的。该方法包括在N ₂ H ₄和Co ²⁺的存在下对EMD进行简单的湿法处理。EMD对ORR具有固有的活性，比化学合成的MnO _2更重要，但对逆反应OER无效。在这里，少量Co的极高的质量活度被引入到$\gamma$-MnO ₂增强了其OER活性，而没有抵消ORR活性。其结果是，超电势在10mA厘米^-2的OER被测量为440毫伏，而在-1毫安厘米^-2在ORR为447毫伏。它们的总和（η _OER + η _ORR）的887毫伏比（1040毫伏）原始EMD的小得多，通过仅26毫伏从的Pt / C的不同。