Platinum chloride-graphite intercalated compounds (PtCl4-GICs) with a stage three structure were produced by mixing platinum tetrachloride and graphite at 723 K under 0.3 MPa of chlorine atmosphere. Two-dimensional platinum nanosheets with a thickness of 2-3 nm and a width of 5-300 urn were formed between graphite layers by hydrogen reduction Of PtCl4-GICs at 573 K. The sheets had a number of hexagonal holes and edge angles of 120 degrees, owing to the limited aggregation of the intercalated platinum chloride molecules to platinum sheets along regular hexagonal nets of carbon atoms between graphite layers.