Prussian Blue Analogues–Derived CoFe–B Nanocubes with Increased Specific Surface Area and Modulated Electronic Structure as Enhanced Oxygen Evolution Electrocatalysts

Abstract

Questing for efficient and inexpensive catalysts for electrochemical water splitting is vital for energy conversion and storage. Herein, Prussian blue analogues (PBA)-derived CoFe-based nanomaterials with increased specific surface area and abundant catalytic active sites are utilized as efficient and durable electrocatalysts for oxygen evolution reaction (OER). Due to the adjustable chemical conformation and controllable 3D morphology, CoFe-B nanocubes exhibit an ultrathin nanosheets-wrapped nanocube structure with excellent electrocatalytic performance and remarkable reaction kinetics in 1.0 M KOH aqueous solution. In addition, CoFe-B nanocubes cost overpotentials of 261 and 338 mV at corresponding current densities of 10 and 200 mA cm À2 , respectively, with small Tafel slope of 61 mV dec À1 for OER, which displays higher catalytic capability than the reported commercial RuO 2. The outstanding electrocatalytic performance can be mainly attributed to the unique ultrathin nanosheetswrapped nanocube structure which is generated from calcination. This work not only provides a new way for the application of PBA but also obtains an alternative for efficient electrocatalysis.

Borate Anion Dopant Inducing Oxygen Vacancies over Co3O4 Nanocages for Enhanced Oxygen Evolution

“…The obvious change in binding energy may be attributed to the introduction of more borate anions when reacting the ZIF-67 precursor with the BBS solution (Table S3), which can be further confirmed by the highresolution B 1s XPS spectra of B-Co3O4-2@ZIF-67 (Figure 4c). As shown, the peak at 192.3 eV, which is assigned to three-coordinated borate species (B-O), proved that boron atoms in the form of borate were incorporated into the crystal structure of Co3O4 [63,64]. In this process, B4O7 2− partially replaced the oxygen anions (O 2− ) in the Co3O4 lattice, thereby destroying the original crystalline structure and producing a large number of oxygen vacancy defects [27,65].…”

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

“…Moreover, FCNSNP on GCE undergoes an activation in the first 15 h and then shows a steady performance for the next 5 h as revealed by the chronoamperometry responses recorded at a fixed potential of 1.558 V versus RHE ( Figure S16 B). This enhancement in OER performance and stability can be explained by the electrochemical activation of the electrode during electrocatalytic OER because of formation of thermodynamically stable oxyhydroxide phases on the surface, which was intensively studied previously ( Amin et al., 2021 ; Jin, 2017 ; Xu, 2019 ; Yang et al., 2020a ).…”

Porous Nanoarchitectures of Nonprecious Metal Borides: From Controlled Synthesis to Heterogeneous Catalyst Applications

“…Several representative strategies, including lyotropic liquid crystals (LLCs), self-assembly of cationic surfactants, self-assembly of block copolymers, aggregation of nanoblocks, metal–organic framework (MOF)-derived pores, and heterostructure engineering, for preparing porous TMBs are presented in Figure . Different methods are favorable for fabricating different types of porous morphologies, such as two-dimensional (2D) hexagonal mesopores, worm-like mesopores, well-defined open mesopores, aggregated pores, MOF-derived pores, and hybridized pores, among others ,− (Table ).…”

“…Copyright 2018, Royal Society of Chemistry. (g–i) Reproduced with permission from ref . Copyright 2021, Wiley-VCH.…”

“…For example, increasing the temperature to 1000 °C resulted in a large amount of aggregated CoB block, whereas overexcessive B source caused the formation of amorphous B nanotubes. A porous network structure of CoFe−B nanocubes 86 with rough surfaces and ultrathin nanosheets was obtained by the calcination of CoFe−Prussian blue analog (CoFe−PBA) nanocubes physically mixed with boric acid at 450 °C under Ar gas flow (Figure 6g). The SEM image (Figure 6h) displays the ultrathin nanosheet-wrapped nanocube structure of CoFe− B and the uniform distribution of Co, Fe, and B in CoFe−B, which was determined by the EDS mapping images (Figure 6i).…”