Boosting Overall Water Splitting via FeOOH Nanoflake-Decorated PrBa_0.5Sr_0.5Co₂O_5+δ Nanorods

Abstract

The development of an efficient, robust, and low-cost catalyst for water electrolysis is critically important for renewable energy conversion. Herein, we achieve a significant improvement in electrocatalytic activity for both the oxygen-evolution reaction (OER) and the hydrogen-evolution reaction (HER) by constructing a novel hierarchical PrBa 0.5 Sr 0.5 Co 2 O 5+δ (PBSC)@FeOOH catalyst. The optimized PBSC@FeOOH-20 catalyst consisted of layered perovskite PBSC nanorods and 20 nm thick amorphous FeOOH nanoflakes exhibiting an excellent electrocatalytic activity for the OER and the HER in 0.1 M KOH media, delivering a current density of 10 mA cm −2 at overpotentials of 390 mV for the OER and 280 mV for the HER, respectively. The substantially enhanced performance is probably attributed to the hierarchical nanostructure, the good charge-transfer capability, and the strong electronic interactions of FeOOH and PBSC. Importantly, an alkaline electrolyzer-integrated PBSC@FeOOH-20 catalyst as both the anode and cathode shows a highly active overall water splitting with a low voltage of 1.638 V at 10 mA cm −2 and high stability during continuous operation. This study provides new insights into exploring efficient bifunctional catalysts for overall water splitting, and it suggests that the rational design of the oxyhydroxide/perovskite heterostructure shows great potential as a promising type of electrocatalysts.

Enhancing oxygen and hydrogen evolution activities of perovskite oxide LaCoO3via effective doping of platinum

“…The Tafel slopes are 120, 40 and 30 mV dec À1 when the HER is determined by the Volmer, Heyrovsky and Tafel processes, respectively. 31 As shown in Fig. 4b, the Tafel slope values of all the investigated samples are close to 120 mV dec À1 , indicating that the Volmer reaction might be the determining step of HER catalysis.…”

“…In contrast, HER proceeds through two steps. 31,40 The rst step is a Volmer reaction (H 2 O + e À / H ads + OH À ), which is the reduction of water to H atoms and OH À species, then the intermediates are adsorbed onto the surface of the catalysts. The second step is either a Heyrovsky reaction (H 2 O + H ads + e À / H 2 + OH À ) or Tafel reaction (H ads + H ads / H 2 ), where the former is an electrochemical desorption step and the latter is a chemical desorption one.…”

“…Furthermore, there have been few perovskite oxides studied as OER and HER bifunctional electrocatalysts. [15][16][17][30][31][32] In the present paper, we report our ndings on enhancing OER and HER activities by doping minor precious metal Pt into perovskite oxide LaCoO 3 in an alkaline condition. LaCo 1Àx Pt x -O 3Àd (x ¼ 0, 0.02, 0.04, 0.06, 0.08) perovskite (denoted as LC, LCP2, LCP4, LCP6, and LCP8, respectively) were prepared via the citric acid-ethylenediaminetetraacetic acid (CA-EDTA) complexing sol-gel method.…”

Smart Control of Composition for Double Perovskite Electrocatalysts toward Enhanced Oxygen Evolution Reaction

“…ChemSusChem 2019, 12,5111-5116 www.chemsuschem.org was at the top level among perovskite-basede lectrocatalysts. [37][38][39][40] The good water splitting performance was further demonstrated by the excellent stability,d elivering ar elative steady voltage from 1.57 to 1.63 Va t1 0mAcm À2 for 150 h (Figure 3d,i nset).…”

“…The excellent OER performance of SFC0.2MC0.4 allowed the construction of a home‐made two‐electrode system for overall water splitting in 1.0 m KOH, with SFC0.2MC0.4 and Pt/C serving as the anode and cathode, respectively. As shown in Figure d, it only needed a cell voltage of 1.57 V to support a current density of 10 mA cm −2 , which was at the top level among perovskite‐based electrocatalysts . The good water splitting performance was further demonstrated by the excellent stability, delivering a relative steady voltage from 1.57 to 1.63 V at 10 mA cm −2 for 150 h (Figure d, inset).…”