"public contribution" is correct and can be used in written English.
Example: Local businesses rely on public contribution to fund important community programs.
Both were privately funded with a small public contribution.
Every decision is a public contribution or a destructive act.
In six months, the public contribution had gone from minimal to £60m.
There's not going to be a public contribution, and that's everyone's right".
It was also promised that the public contribution to the project was minimal.
Funds are provided by direct public contribution and through the local federated fund.
Before we do, we figured we'd ask for public contributions.
But the biggest hurdle is money, because the foundation relies on public contributions.
But some estimates for public contributions have reached tens of billions of dollars.
Seven scholarships of $6,000 a year are being financed from public contributions.
While he was alive, Wilson had dabbled in philanthropy, giving money to medical institutions and others, but none of his public contributions had been particularly large.
