Effects of hydrogen impurity on diamond crystal growth process

► We investigate the effects of hydrogen impurity on diamond crystallization. ► XRD and Raman shows that hydrogen impurity changes the characteristics of catalyst and graphite. ► Much high pressure and temperature are required for diamond nucleation and growth. ► Hydrogen impurity could significantly influence diamond morphology. ► FTIR shows that hydrogen atoms can substitute the carbon atoms in the form of sp3CH2.