Results and discussion The bare CNS electrode (Supporting Information Figure S1) wascharacterized in our previous study as a dense nanotexturedcarbon film terminated by randomly oriented nanospikes approximately 50–80 nm in length, where each nanospike consists of layers of puckered carbon ending in a ~ 2 nm wide curled tip.[15]The film is grown by a rela tively simple direct-current plasma-enhanced chemical vapor deposition reaction using acetylene and ammonia as reagents