When graphite is exposed to simultaneous irradiation by H + and O + , in addition to the H + -induced hydrocarbon and O + -induced CO and CO 2 formation, water is also formed. The present investigation explores the effect of the presence of boron in graphite on water formation. The results show that B-doped graphite specimens (∼15 at.% B) exposed to simultaneous O + and H + irradiation produce less water when compared to pure graphite under similar irradiation. The concept of the formation of ‘water-precursors’ at the end of the O + range is proposed to explain the observed effect.