We performed density functional theory calculations to investigate the uniaxial strain effects on the elastic and electronic properties of chair and boat conformers of fully hydrogenated XC (X=Si, Ge, Sn) monolayers. The stress-strain relation shows that hydrogenation reduces their ideal strength, but the critical strain along the zigzag direction increases significantly. When hydrogenated, all the chair conformers are ΓΓ-direct bandgap semiconductors, and of which, the chair conformers GeCH2 and SnCH2 almost maintain the ΓΓ-direct band gap in our considered uniaxial strain range. Besides, the band gap of boat conformers SiCH2 and SnCH2 experiences an indirect-direct transition with a small zigzag-direction strain. Furthermore, the calculated results of the structural and electronic properties of the XC/XCH2 vdW heterostructures showed that XC/XCH2(chair) vdW heterostructures owe type-II band alignment characteristics. Such the band alignments are expected to facilitate the spatial separation of electrons and holes after photoexcitation, which can be utilized in photovoltaic devices.