How to say "dull the knife"?
Dull (adjective) as in 'a dull knife' is 钝 in Mandarin. There is not a two-character version for it.
Dull (vt.) as in 'dull the knife' is 使..变钝, literally 'make .. become dull'.
Example of 钝 (adjective):

It's impossible to cut a pineapple with such a dull knife.
用一把这么钝的刀子切菠萝是不可能的。

To translate your sentence, which is also an example of 使..变钝:

Using the knife on these types of surfaces will dull the knife.
在这些类型的表面上用刀会使刀变钝。

Related words:

(Knife or blade) sharp (adjective): 快 or 锋利.

快 must be used in the same sentence as the noun (刀), otherwise it doesn't mean 'sharp'. 锋利 can be used standalone.

Sharpen the knife (V+O): 磨刀.

An example using all these words:

刀子用多了会变钝，磨一磨就又变快了。
Knife becomes dull after some use. Burnish it and it will be sharp again.