A Perovskite Nanorod as Bifunctional Electrocatalyst for Overall Water Splitting

Abstract

The development of highly efficient and low‐cost electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is paramount for water splitting associated with the storage of clean and renewable energy. Here, this study reports its findings in the development of a nanostructured perovskite oxide as OER/HER bifunctional electrocatalyst for overall water splitting. Prepared by a facile electrospinning method, SrNb0.1Co0.7Fe0.2O3–δ perovskite nanorods (SNCF‐NRs) display excellent OER and HER activity and stability in an alkaline solution, benefiting from the catalytic nature of perovskites and unique structural features. More importantly, the SNCF‐NR delivers a current density of 10 mA cm−2 at a cell voltage of merely ≈1.68 V while maintaining remarkable durability when used as both anodic and cathodic catalysts in an alkaline water electrolyzer. The performance of this bifunctional perovskite material is among the best ever reported for overall water splitting, offering a cost‐effective alternative to noble metal based electrocatalysts.

Evaluation of A-Site Ba2+-Deficient Ba1−xCo0.4Fe0.4Zr0.1Y0.1O3−δ Oxides as Electrocatalysts fo

“…To assess this, a chronopotentiometric (CP) test (Figure 8) was carried out and the voltammograms (Figure 8) before and after the CP test for 2 h at 20 mA cm −2 were compared. Pt/C exhibits the highest initial activity but undergoes a rapid degradation during the CP test, corresponding to its poor HER durability as reported [14]. In sharp contrast, BaCFZY even exhibits a decreasing operating overpotential over the same testing period, demonstrating its superior stability in the long-term electrochemical process.…”

“…Via the narrow spectra of high-resolution XPS as shown in Figure 4, the peaks of Fe 2p 3/2 , Fe 2p 1/2 , and Co 2p 1/2 can be clearly identified in all samples, while it is difficult to separate out the Co 2p 2/3 peaks due to the overlap between Co 2p 3/2 and Ba 3d 5/2 main lines [14]. Meanwhile, the negative shift of the characteristic peaks of Fe 2p 3/2 , Fe 2p 1/2 , and Co 2p 1/2 together with Co 2p 3/2 @Ba3d 2/5 can be observed, indicating that the reduction of both Co and Fe cations in Ba 1− x CFZY as compared to BSCF [13, 21].…”

“…In a perovskite structure, the octahedral building containing a transition-metal cation and contiguous 6-fold coordinated oxygen anions could play the role of heterojunctions and possibly be reactive sites for HER. Very recently, the perovskite oxides Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3− δ , Pr 0.5 (Ba 0.5 Sr 0.5 ) 0.5 Co 0.8 Fe 0.2 O 3− δ , and SrNb 0.1 Co 0.7 Fe 0.2 O 3− δ were found to be highly active and stable for HER [13, 14], which demonstrate the remarkable effectiveness of perovskite oxides as candidates for the HER catalyst. However, up to now, studies on the activity of perovskite oxide for HER are scanty, due to the unclear HER mechanism on these materials.…”

Solar‐to‐Hydrogen Energy Conversion Based on Water Splitting

“…[87][88][89][90] To reduce the activation energies of HER and OER, numerous catalysts have been developed and loaded in various forms on the surfaces of light-absorbing materials. [87][88][89][90] To reduce the activation energies of HER and OER, numerous catalysts have been developed and loaded in various forms on the surfaces of light-absorbing materials.…”

Eutectic‐Derived Mesoporous Ni‐Fe‐O Nanowire Network Catalyzing Oxygen Evolution and Overall Water Splitting

“…To quantify the OER activity, it is important to compare the values of overpotential (η) required to achieve a current density of 10 mA cm −2 , which is always regarded as the benchmark to evaluate the activity of OER catalysts. [11,25,[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] Electrochemical impedance spectroscopy (EIS) could offer an opportunity to investigate the underlying factors of catalysts activity. Figure S20 (Supporting Information) shows the OER current density of the catalysts normalized by BET surface area.…”