openssl pkcs12 -in input.pfx -out mycerts.crt -nokeys -clcerts

openssl x509 -inform pem -in mycerts.crt -outform der -out mycerts.cer

openssl pkcs12 -in testcert.pfx -out C:\TLS\powershellcert.pem -nodes

openssl pkcs12 -in testcert.pfx -nocerts -out [keyfilename-encrypted.key]

Download and install openssl from https://slproweb.com/products/Win32OpenSSL.html