The replacement of a noble metal catalyst by base metals presents a great challenge for low-temperature CO and volatile organic compounds oxidation. Cu/Ce-based catalysts are expected to achieve this goal with excellent performance, among which the main active sites still need to be further explored. For this reason, CuCe catalysts were further compounded with typical elements (cobalt, Co) to study the main active sites and compositing effect by in-situ enhanced Raman and in-situ ultralow-temperature DRIFTS technologies. The main active site for both CuCe and CuCoCe catalysts was the same Cu-O