Invalid resource property cloudformation

I'm attempting to use CloudFormation to automate some build deployments. I'm right now trying to create a VPC with a public subnet, but I keep getting this error

A client error (ValidationError) occurred when calling the ValidateTemplate operation: Invalid template resource property 'PublicSubnet'

The portion I have in the template is as follows:

       "PublicSubnet" : {
        "Type": "AWS::EC2::Subnet",
        "Properties": {
            "CidrBlock": "10.0.1.0/24",
            "Tags": [
                {
                    "Name": "public-1"
                },
                {
                    "VpcId": {
                        "Ref": "DemoVPC"
                    }
                }
            ]
        },

Any guidance would be appreciated.