In photosynthesis, chlorophyll is the catalyst which helps in forming of glucose and oxygen in plants. Now, since a catalyst DECREASES the activation temperature, the plant can use just sunlight as the energy input. Now, how much temperature is needed to make glucose without chlorophyll. Like in a test tube.
Photosynthesis Formula:- 6CO2 + 6H2O ->(chlorophyll, sunlight) C6H12O6 + 6O2

It will not work, a biological catalyst works different as inorganic catalyst. Only to mix CO2 and water gives sparkling water nothing else.  Its not only a matter of temperature. At least it needs nature or let say influence of higher spirit like god.

no free oxygen and food then

Correct. If it would so easy then it would be developed already.

is there a alternative catalyst for chlorophyll

No, otherwise we would not have a problem with the climatic and energy.

how do we find a suitable catalyst? like what are the processes to find and test them?