Can you tell me if my idea for an invention would work or not or maybe how to make it work?

You are on the edge of creation to take molecules out of the air you have certain atoms that cannot be made into something it does not have. You would need solid attributed atoms to make a solid hydrogen and oxygen cannot make steel but there is pollution and other chemicals in the air you can use. But the amount in the atmosphere is very small compared to creating something solid. You would need to have the required building materials to do that and have a machine to break each molecule into atoms then rebuild into what you require. It would be very exspenisive and would require you had more materials than were available in the atmosphere. It's a great Idea and I hope you look into it more I would love to see that machine in action. Goodluck!