No, catch-up contributions must be made before the end of the plan year. It's too late to make catch-up elective deferrals for 2019. Any elective deferrals you make from your pay in 2019 will be deferrals for 2019, not 2018.
For additional information, see the IRS article Retirement Topics – Catch-up contributions.
[Edited 3-10-2020|6:32 am PST]
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