What act removed the barriers of voting 1965 and increased the participation of black voters?

The act is called the Voting Rights Act of 1965.

This act, signed into law by Lyndon B. Johnson, helped to remove legal barriers that African-Americans faced when it came to voting. For example, African-Americans were unfair targets of things like literacy tests, poll taxes, and the grandfather clause. All three of these barriers were put in place to limit the amount of African-American citizens voting in local, state, and national elections.

This law ensured that African-Americans received the same protection guaranteed to them under the 15th amendment.