Postgres 11 - Range Partitioning on a Date Column with NULL values
PostgreSQL 11 allows you create a default partition for range-partitioned tables, which will receive the NULL values.
You can add a check constraint demanding the column be NULL, if you want to prevent other rows not covered by existing partitions from going into that default table.
create table for_nulls PARTITION OF parent_table (check (date_requested is null)) DEFAULT;