XPS is a surface analysis technique which detect what presents on the top 10nm of the surface. In this case, samples are easily being oxidized or contaminated in different ways. In your C1s, while the biggest peak which fall around 285eV seems to be a C-C/C-H peak and then indeed there look to be another 2 peaks to the left. They can be C-O, C=O compound or even C-N...etc depending on within your full survey spectrum (full Binding Energy range scan) as what other elements are presented. For example, if O is presented, it could be CO some kinds of bonding compound is/are presenting.