When ammonium fluoroborate is excessive, a large number of F atoms are embedded in the carbon material and completely occupy the sites of the N and B species, making it difficult for N and B atoms to be embedded in the carbon material.
When ammonium fluoroborate is excessive, a large number of F-atoms are embedded in carbon materials that completely occupy the ni and B species, which make it difficult for N and B atoms to embed carbon materials
When ammonium fluoborate is excessive, a large number of F atoms are embedded in the carbon materials, occupying the sites of N and B species completely, which makes it difficult for N and B atoms to be embedded in the carbon materials<br>