The origin of instability or even disappearance of the superlubricity state in hydrogenated amorphous carbon (a-C:H) film in the presence of oxygen or water molecules is still controversial. Here, we address this puzzle regarding the tribochemical activities of sliding interfaces at the nanoscale. The results reveal that gaseous oxygen molecules disable the antifriction capacity of a-C:H by surface dehydrogenation of tribo-affected hydrocarbon bonds. In comparison, oxygen incorporation into the hydrocarbon matrix induces the formation of a low-density surface shear band, owing to which the friction state depends on the oxygen content. High friction of a-C:H film in humid environment originates from the “tumor-like” heterogeneous structures as formed in the highly oxidized tribolayer. Notably, an appropriate doping of silicon can completely shield the moisture effect by forming a silica-like tribolayer. These outcomes shed substantial lights upon the roadmap for achieving robust superlubricity of carbon films in a wide range of environments.

在存在氧气或水分子的情况下，氢化非晶碳（aC：H）膜中超润滑状态的不稳定性甚至消失的根源仍然存在争议。在这里，我们解决了有关纳米级滑动界面的摩擦化学活性的难题。结果表明，气态氧分子通过受摩擦的烃键的表面脱氢作用而使aC：H的减摩能力失效。相比之下，将氧掺入烃基体中会引起低密度表面剪切带的形成，由于该剪切带，摩擦状态取决于氧气含量。aC：H膜在潮湿环境中的高摩擦力起因于在高度氧化的摩擦层中形成的“肿瘤样”异质结构。值得注意的是 适当的硅掺杂可以通过形成类似二氧化硅的摩擦层来完全屏蔽湿气影响。这些成果为在各种环境中实现强大的碳膜超润滑性的路线图提供了重要启示。