Metal‐Organic Framework Glass Catalysts from Melting Glass‐Forming Cobalt‐Based Zeolitic Imidazolate Framework for Boosting Photoelectrochemical Water Oxidation

Abstract

Sluggish oxygen evolution kinetics and serious charge recombination restrict the development of photoelectrochemical (PEC) water splitting. The advancement of novel metal–organic frameworks (MOFs) catalysts bears practical significance for improving PEC water splitting performance. Herein, a MOF glass catalyst through melting glass‐forming cobalt‐based zeolitic imidazolate framework (Co‐agZIF‐62) was introduced on various metal oxide (MO: Fe2O3, WO3 and BiVO4) semiconductor substrates coupled with NiO hole transport layer, constructing the integrated Co‐agZIF‐62/NiO/MO photoanodes. Owing to the excellent conductivity, stability and open active sites of MOF glass, Co‐agZIF‐62/NiO/MO photoanodes exhibit a significantly enhanced photoelectrochemical water oxidation activity and stability in comparison to pristine MO photoanodes. From experimental analyses and density functional theory calculations, Co‐agZIF‐62 can effectively promote charge transfer and separation, improve carrier mobility, accelerate the kinetics of oxygen evolution reaction (OER), and thus improve PEC performance. This MOF glass not only serves as an excellent OER cocatalyst on tunable photoelectrodes, but also enables promising opportunities for PEC devices for solar energy conversion.

Modulation of charge-transfer behavior via adaptive interface treatment for efficient photoelectrochemical water splitting

“…S2,† BV film could be assigned to a monoclinic structure (PDF#14-0688), as supported by previous works. 44–47 In addition, characteristic Raman peaks for BV located at 210.0, 324.0, 366.0, 640.0, 710.0 and 826.0 cm −1 (Fig. S3†) indicated that the BV photoelectrodes have been prepared.…”

“…27 To further boost large-scale application of this technology, tremendous efforts have been made aiming at improving charge separation and boosting the fast OER kinetics of semiconductor (SC)-based photoelectrodes, such as doping, 28 constructing heterojunctions, 29 plasmonic metal nanoparticle decoration, 30 and electrocatalyst loading. 31–37 In particular, the rational design of photoanodes with electrocatalysts has been considered. Recently, direct loading of transition metal hydroxide (TMH) on SCs has led to improved PEC performance.…”

Unveiling the role of a ground state charge transfer complex in carbon nanoparticles for highly efficient metal-free solar hydrogen production

“…1–3 In this context, photocatalytic and photoelectrochemical water splitting has emerged as a desirable approach. 4–8 Green hydrogen through photocatalysis is one of these fuels that has gained serious interest due to its excellent energy density and minimum greenhouse emissions. 9–11 Over the past few decades, research on HER active photo-catalysts has primarily focused on metal oxides, organic–inorganic hybrids, and polymeric carbon nitride systems, which have drawbacks like metal-based toxicity, water insolubility, a wide band gap, and high charge carrier recombination limiting their overall efficiency.…”

Superhydrophilic CoFe Dispersion of Hydrogel Electrocatalysts for Quasi-Solid-State Photoelectrochemical Water Splitting

“…Photoelectrochemical (PEC) water splitting to produce hydrogen is considered one of the most promising approaches for converting solar energy into sustainable energy. − Since water oxidation is a slow four-electron transfer process that limits water decomposition, development of an efficient and inexpensive semiconductor system is the key to improving PEC water splitting. Most of the photoanode materials, e.g., BiVO, − WO 3 , − and Fe 2 O 3 , − etc., suffer from low charge transfer rate, serious charge recombination, and poor water oxidation kinetics, which limit PEC performance.…”

“…Photoelectrochemical (PEC) water splitting to produce hydrogen is considered one of the most promising approaches for converting solar energy into sustainable energy. − Since water oxidation is a slow four-electron transfer process that limits water decomposition, development of an efficient and inexpensive semiconductor system is the key to improving PEC water splitting. Most of the photoanode materials, e.g., BiVO, − WO 3 , − and Fe 2 O 3 , − etc., suffer from low charge transfer rate, serious charge recombination, and poor water oxidation kinetics, which limit PEC performance. Although different strategies, including morphology modulation, , defect fabrication, , elemental doping, − heterostructures, − and co-catalyst/passivation layer deposition − have been developed to address these issues to enhance water oxidation reaction, the low surface reactivity limits solar-to-hydrogen conversion efficiency.…”