Option Explicit
Sub Tst()
Dim i As Long
Dim LastRow As Long
Dim Coll As Collection
Application.ScreenUpdating = False
Columns("I:I").Clear
LastRow = Range("A65536").End(xlUp).Row
Set Coll = New Collection
For i = 2 To LastRow
On Error Resume Next
Coll.Add Cells(i, 1) & " " & Cells(i, 2), CStr(Cells(i, 1) & Cells(i, 2))
If Err.Number = 457 Then Err.Clear
Next i
For i = 1 To Coll.Count
Cells(i + 1, 9) = Coll(i)
Next i
Set Coll = Nothing
Range("J1").Select
Application.ScreenUpdating = True
End Sub