Porous Mn-Doped FeP/Co3 (PO4 )2 Nanosheets as Efficient Electrocatalysts for Overall Water Splitting in a Wide pH Range.

Abstract

Development of highly active and stable electrocatalysts for overall water splitting is important for future renewable energy systems. In this study, porous Mn-doped FeP/Co3 (PO4 )2 (PMFCP) nanosheets on carbon cloth are utilized as a highly efficient 3 D self-supported binder-free integrated electrode for the oxygen evolution and hydrogen evolution reactions (OER and HER) over a wide pH range. Specifically, overpotentials of 27, 117, 85 mV are required for the PMFCP nanosheets to attain 10 mA cm-2 for HER in 0.5 m H2 SO4 , 1.0 m phosphatebuffered saline (PBS), and 1.0 m KOH, respectively. In addition to the excellent performance for HER electrocatalysis, PMFCP nanosheets were also efficient electrocatalysts for the OER. Thus, the PMFCP nanosheets can serve as anodes and cathodes for overall water splitting (OWS). The OWS working voltages to attain 10 mA cm-2 are found to be 1.75, 1.82, and 1.61 V in acid, neutral, and alkaline electrolytes, respectively. Chronopotentiometric tests show that the PMFCP electrode can maintain its excellent pH-universal OWS activity for more than 30 000 s. This work also provides new insights into developing high-performance electrocatalysts for water splitting over a wide pH range. The improvement in electrochemical performance by introduction of Mn dopant and nano-holes offers new opportunities in the development of effective electrodes for other energy-related applications.