Rational design of Ruddlesden–Popper perovskite electrocatalyst for oxygen reduction to hydrogen peroxide
Ning Han, Shihui Feng, Wei Guo, Omar Martínez-Mora, Xiaolin Zhao, Wei Zhang, Sijie Xie, Zhenyu Zhou, Zhiwei Liu, Qiong Liu, Kai Wan, Xuan Zhang, Jan Fransaer
Abstract
Abstract Although the oxygen reduction process to hydrogen peroxide (H 2 O 2 ) is a green option for H 2 O 2 generation, the low activity and selectivity hindered the industry's process. In recent years, the electrochemical synthesis of H 2 O 2 through a 2e – transfer method of oxygen reduction reaction (ORR) has piqued the interest of both academics and industry. Metal oxide catalysts have emerged as a novel family of electrochemical catalysts due to their unusual physical, chemical, and electrical characteristics. In this work, we first developed a Ruddlesden–Popper perovskite oxide (Pr 2 NiO 4+δ ) as a highly selective and active catalyst for 2e – ORR to produce H 2 O 2 . Molybdenum was introduced here to adjust the oxidation states of these transition metals with successful substitution into Ni‐site to prepare Pr 2 Ni 1‐x Mo x O 4+δ , and the molybdenum substitution improves the H 2 O 2 selectivity during the ORR process, in 0.1 M KOH, from 60% of Pr 2 NiO 4+δ to 79% of Pr 2 Ni 0.8 Mo 0.2 O 4+δ at 0.55 V versus RHE. A limiting H 2 O 2 concentration of 0.24 mM for Pr 2 NiO 4+δ and 0.42 mM for Pr 2 Ni 0.8 Mo 0.2 O 4+δ was obtained at a constant current of 10 mA/cm 2 using a flow‐cell reactor using a gas‐diffusion electrode.