The high oxygen storage capacity of exhaust gas treatment catalysts is a desirable feature for stabilizing fuel conversion at lambda variations for stoichiometric engine performance. Pd catalysts supported on Co₃O₄, Al₂O₃, CeO₂ and ZrO₂, as well as Pd-free Co₃O₄, were evaluated using methane combustion at sub-stoichiometric oxygen-to-fuel ratios at temperatures below 550 °C. The product analysis was performed with an online mass spectrometer calibrated for CH₄, O₂, CO₂, H₂O, CO and H₂. Only both cobalt catalysts demonstrated the insensitivity of the methane conversion to O₂/CH₄ variations. The Pd/Co₃O₄ catalyst was the only catalyst that produced a 40 % increase in exit gas flow above the feed gas mass flow rate at ignition (light-off) between 400 °C and 550 °C, with the same decrease upon extinction. The oxygen from the catalyst participated in the combustion, even while the molecular oxygen supplies lasted. Selected catalysts were analyzed by temperature-programmed desorption, reduction in H₂ and surface reaction with CH₄. In the absence of O₂ in the feed, Pd/Co₃O₄ supplied a “tithe” of its bulk oxygen at temperatures of 400−550 °C for the formation of CO₂ and H₂O, while Pd/Al₂O₃ provided only PdO-associated low oxygen for the CO and H₂ formation. Co₃O₄ surpasses CeO₂ in its oxygen-donating properties at low temperatures and at the conditions tested and, thus, is potentially capable of widening the operational lambda window of stoichiometric combustion to a larger extent than ceria.

排气处理催化剂的高储氧能力是在化学计量的发动机性能下以λ变化稳定燃料转化率的理想特征。在低于550的温度下使用亚化学计量的氧/燃料比燃烧甲烷，评估了负载在Co ₃ O ₄，Al ₂ O ₃，CeO ₂和ZrO ₂上的Pd催化剂以及不含Pd的Co ₃ O ₄。 ℃。使用在线质谱仪对CH ₄，O ₂，CO ₂，H ₂ O，CO和H ₂进行校准，对产品进行分析。仅两种钴催化剂均显示甲烷转化为O ₂ / CH ₄变化的不敏感性。Pd / Co ₃ O ₄催化剂是唯一在400°C至550°C之间着火（起燃）时，进料气质量流速以上，出气量增加40％的催化剂，当温度升高时，出气量增加40％灭绝。即使分子氧供应持续，来自催化剂的氧气也参与了燃烧。通过程序升温脱附，H ₂还原和与CH _4的表面反应来分析选定的催化剂。在进料中没有O ₂的情况下，Pd / Co ₃ O ₄在400-550°C的温度下，其供应的大量氧气“滴定”以形成CO ₂和H ₂ O，而Pd / Al ₂ O ₃仅提供了与PdO相关的低氧来形成CO ₂和H ₂。在低温和测试条件下，Co ₃ O ₄的供氧性能超过了CeO ₂，因此，与二氧化铈相比，Co ₃ O ₄有可能在更大的程度上扩大化学计量燃烧的操作λ窗口。