Water Oxidation Performance Enhanced by Electrochemically Designed Vacancies on a Prussian Blue Catalyst

Abstract

Prussian blue analogues are one of the most promising examples of water oxidation catalysts presenting great performance, activity, and stability under mild conditions. Herein, we report an alternative methodology to synthesize the Prussian blue, obtaining a catalyst with vacancies created by an electrochemical method. This catalyst showed an outstanding activity, with an onset overpotential of 361 mV. Using pyridine as a molecular probe, we identified the presence of vacant Fe2+ sites, and the quantification of these sites allowed us to estimate a TOF number of 0.2170 s–1 for the water oxidation reaction. These results indicate that defect engineering is a versatile strategy to boost the catalytic activity in Prussian blue analogues by increasing the number of active sites.

Elucidating Gas Evolution of Prussian White Cathodes for Sodium‐ion Battery Application: The Effect of Electrolyte and Moisture

“…At this point, two effects of increased water content shall be discussed. At high potentials and water contents (undried electrodes), and especially during overcharge, one might assume water oxidation to occur via electrocatalysis by the de‐sodiated PW framework, [97] yet no O 2 evolution was detected, as shown in Figure S5a and b (Supporting Information). The high H 2 evolution amounts, i. e. curve integrals as listed in Table S2 (Supporting Information), can be converted into water loss from the CAM, as exemplified in Table S4 and Figure S6 (Supporting Information), yielding a water release between 1.15 and 1.37 wt% during regular cycling and 4.93 to 6.44 wt% during overcharge.…”

Co-Prussian blue analogue supported on graphene-based materials as an electrocatalyst for OER at neutral pH

“…The ECSA of the samples were obtained according to the Randles-S ˇevc ˇı ´ck equation, [41][42][43] where I p is the peak current, n is the number of electrons involved in the electrochemical process, A ECSA is the electrochemical surface area, D is the diffusion coefficient (9.10 Â 10 À6 cm 2 s À1 for [Ru(NH 3 ) 6 ] 3+ ), C is the concentration of the redox probe and n is the scan rate:…”

“…The ECSA of the samples were obtained according to the Randles-S ˇevc ˇı ´ck equation, [41][42][43] where I p is the peak current, n is the number of electrons involved in the electrochemical process, A ECSA is the electrochemical surface area, D is the diffusion coefficient (9.10 Â 10 À6 cm 2 s À1 for [Ru(NH 3 ) 6 ] 3+ ), C is the concentration of the redox probe and n is the scan rate: K obs was obtained by the Nicholson method [41][42][43] using the following equation: where D is the diffusion coefficient, a is the charge transfer coefficient (assumed to correspond to 0.5), n is the number of electrons involved in the electrochemical process, F is the Faraday constant, n is the scan rate, R is the gas constant, T is the temperature and DE p is the peak-to-peak separation:…”

“…K obs was obtained by the Nicholson method [41][42][43] using the following equation: where D is the diffusion coefficient, a is the charge transfer coefficient (assumed to correspond to 0.5), n is the number of electrons involved in the electrochemical process, F is the Faraday constant, n is the scan rate, R is the gas constant, T is the temperature and DE p is the peak-to-peak separation:…”