Boosting the overall electrochemical water splitting performance of pentlandites through non-metallic heteroatom incorporation

Mohamed Barakat Zakaria Hegazy; Karim Harrath; David Tetzlaff; Mathias Smialkowski; Daniel Siegmund; Jun Li; Rui Cao; Ulf-Peter Apfel

doi:10.1016/j.isci.2022.105148

Boosting the overall electrochemical water splitting performance of pentlandites through non-metallic heteroatom incorporation

iScience. 2022 Sep 15;25(10):105148. doi: 10.1016/j.isci.2022.105148. eCollection 2022 Oct 21.

Authors

Mohamed Barakat Zakaria Hegazy^{1

2}, Karim Harrath^{3

4}, David Tetzlaff^{1

5}, Mathias Smialkowski¹, Daniel Siegmund^{1

5}, Jun Li^{3

4}, Rui Cao⁶, Ulf-Peter Apfel^{1

5}

Affiliations

¹ Inorganic Chemistry I, Faculty for Chemistry and Biochemistry, Ruhr University Bochum, 44801 Bochum, Germany.
² Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt.
³ Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.
⁴ Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China.
⁵ Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, 46047 Oberhausen, Germany.
⁶ Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.

Abstract

We report on synthesis of the heterotrimetallic pentlandite-type material Fe₃Co₃Ni₃S₈ (FCNS) in presence of suitable phosphorus-(FCNSP) and nitrogen-(FCNSN) donors for the overall electrochemical water splitting. Throughout the experiments, a preferential incorporation of N into the FCNS-lattice is observed whereas the addition of phosphorus generally leads to metal-phosphate-FCNS composites. The obtained FCNSP, FCNSN, and FCNSNP facilitate the oxygen evolution reaction (OER) at 100 mAcm^-2 in 1.0M KOH with overpotentials of 479, 440, and 427 mV, respectively, outperforming the benchmark IrO₂ (564 mV) and commercial Ni metal powder (>600 mV). Likewise, FCNSN and FCNSNP reveal an improved performance toward the hydrogen evolution reaction (HER) in 0.5M H₂SO_4, outperforming the pristine FCNS. All materials revealed high stability and morphological robustness during OER and HER. Notably, DFT calculation suggests that N and P doping boost the OER activity of the pristine FCNS, whereas N doping enhances the HER activity.

Keywords: Catalysis; Chemistry; Electrochemical materials science; Inorganic chemistry; Materials science.