| Autor: |
Parker JF; Surface Chemistry Branch, Code 6170, U.S. Naval Research Laboratory, Washington, DC 20375, United States., Kamm GE; Chemistry Department, Pacific Lutheran University , Tacoma, Washington 98447, United States., McGovern AD; Chemistry Department, Pacific Lutheran University , Tacoma, Washington 98447, United States., DeSario PA; Surface Chemistry Branch, Code 6170, U.S. Naval Research Laboratory, Washington, DC 20375, United States., Rolison DR; Surface Chemistry Branch, Code 6170, U.S. Naval Research Laboratory, Washington, DC 20375, United States., Lytle JC; Chemistry Department, Pacific Lutheran University , Tacoma, Washington 98447, United States., Long JW; Surface Chemistry Branch, Code 6170, U.S. Naval Research Laboratory, Washington, DC 20375, United States. |
| Abstrakt: |
Platinum is state-of-the-art for fast electron transfer whereas carbon electrodes, which have semimetal electronic character, typically exhibit slow electron-transfer kinetics. But when we turn to practical electrochemical devices, we turn to carbon. To move energy devices and electro(bio)analytical measurements to a new performance curve requires improved electron-transfer rates at carbon. We approach this challenge with electroless deposition of disordered, nanoscopic anhydrous ruthenium oxide at pyrolytic carbon prepared by thermal decomposition of benzene (RuOx@CVD-C). We assessed traditionally fast, chloride-assisted ([Fe(CN) 6 ] 3-/4- ) and notoriously slow ([Fe(H 2 O) 6 ] 3+/2+ ) electron-transfer redox probes at CVD-C and RuOx@CVD-C electrodes and calculated standard heterogeneous rate constants as a function of heat treatment to crystallize the disordered RuOx domains to their rutile form. For the fast electron-transfer probe, [Fe(CN) 6 ] 3-/4- , the rate increases by 34× over CVD-C once the RuOx is calcined to form crystalline rutile RuO 2 . For the classically outer-sphere [Fe(H 2 O) 6 ] 3+/2+ , electron-transfer rates increase by an even greater degree over CVD-C (55×). The standard heterogeneous rate constant for each probe approaches that observed at Pt but does so using only minimal loadings of RuOx. |
