Bifunctional Multiferroic GdCrO₃ Nanoassemblies for Sustainable H₂ Production Using Electro- and Photocatalysis

Abstract

In the realm of energy storage and conversion powered by electro- or photocatalysts, tremendous efforts are devoted on producing effective and long-lasting oxide catalysts. Here, we demonstrate multiferroic GdCrO3 nanoassemblies synthesized using a solvothermal method. X-ray diffraction (XRD) and XPS studies confirm the orthorhombic formation of GdCrO3. Scanning and high-resolution transmission electron microscopy shows the formation of nanoassemblies. Ferroelectric study reveals the remnant polarization of 2.36 μC cm–2 and oxygen vacancies. In an alkaline media, GdCrO3 nanoassemblies act as an efficacious and resilient oxygen evolution reaction electrocatalyst by showing superior specific activity. Photocatalytic H2 evolution studies show a high H2 evolution rate of 2 mmol h–1 gcat –1 and an apparent quantum yield of 23.2%. The mechanism for significant H2 generation is established by internal electric field-associated charge transfer, as confirmed by XPS measurements.

MoS2 Nanoflower-Deposited g-C3N4 Nanosheet 2D/2D Heterojunction for Efficient Photo/Electrocatalytic Hydrogen Evolution

“…2,6,9 The hydrogen evolution reaction (HER) through PC, EC, and PEC water splitting is a low-energy process primarily driven by photon and electrical energy sources. 9−11 Since the exceptional work of Honda and Fujishima on TiO 2 -assisted PEC water splitting, 12 a diverse range of catalytic systems have been developed such as noble metal, metal oxides, 13 metal chalcogenides, 2 multiferroics, 9,10 graphene-based catalysts, 4 etc., and exploited in PC, EC, and PEC water-splitting operations. 14,15 PC and PEC water splitting thrives upon the advanced activity and elongated stability of visible-light-driven catalytic systems as it comprises nearly 45% of solar energy reaching out to earth.…”

“…The generation of H 2 fuel through ecofriendly and sustainable methods represents a crucial solution to global energy shortages and the pressing problem of global warming. − Over the past few decades, green hydrogen (H 2 ) production through water splitting has gained the interest of researchers due to high gravimetric density of H 2 , which promises to be used effectively as a sustainable energy resource to meet the current energy demand. , For the achievement of scalable water-splitting reactions, a prudent choice of a catalytic system is required to carry out efficient H 2 evolution. , The scalable applicability of green H 2 production is a nontrivial undertaking that requires optimized reactors and catalytic systems that can perform synergistically . Motivated by this approach, photocatalytic (PC), electrocatalytic (EC), and photoelectrocatalytic (PEC) water-splitting strategies are promising pathways for sustainable energy solutions. ,, The hydrogen evolution reaction (HER) through PC, EC, and PEC water splitting is a low-energy process primarily driven by photon and electrical energy sources. − Since the exceptional work of Honda and Fujishima on TiO 2 -assisted PEC water splitting, a diverse range of catalytic systems have been developed such as noble metal, metal oxides, metal chalcogenides, multiferroics, , graphene-based catalysts, etc., and exploited in PC, EC, and PEC water-splitting operations. , PC and PEC water splitting thrives upon the advanced activity and elongated stability of visible-light-driven catalytic systems as it comprises nearly 45% of solar energy reaching out to earth. , In this context, the tunability of the band gap emerges as a critical optical parameter that governs the dynamics of charge carrier separation and migration (e–h+ pair), essential for facilitating efficient visible-light-driven PC and PEC water-splitting processes. , …”

Decorating Thermodynamically Stable (101) Facets of TiO2 with MoO3 for Multifunctional Sustainable Hydrogen Energy and Ammonia Gas Sensing Applications

“…Generally semiconductors that show efficiency toward PC water splitting, exhibit advanced performance against electrocatalytic (EC) and photo/electrochemical (PEC) water splitting operations as well such as Cu 2 O/g-C 3 N 4, g-C 3 N 4, MoS 2, Ag-WO 3, SnO 2 , and CuFe 2 O 4. There are numerous promising semiconductor systems having suitable band structures that have been utilized for the advancement in the visible light-driven hydrogen (H 2 ) evolution. − H 2 as a fuel has several advantages in terms of efficiency, gravimetric density, refueling, and absence of carbon dioxide emission during its operation. , The fabrication of stable, nontoxic, cheap, and efficient photocatalyst and photo/electrocatalyst is the basic requirement for substantial H 2 generation via the OWS green route. − TiO 2 -based photocatalysts have been studied vastly, attributed to their versatile physicochemical properties. However, it comes with several disadvantages as well, such as insufficient utilization of visible light or a higher recombining tendency of participating photocharged carriers.…”

Symbiotic MoO3–SrTiO3 Heterostructured Nanocatalysts for Sustainable Hydrogen Energy: Combined Experimental and Theoretical Simulations

“…Since the rise of the Industrial Revolution, anthropogenic actions have massively impacted the environment and biological cycles of the planet, as validated by the gradual escalation in the rate of extinction of species. − Due to the increase of the demand of ecofriendly and efficient energy resources, research on sustainable energy has tremendously increased to obtain green, clean, and non-toxic energy. Conversion of solar energy into useful energy via hydrogen (H 2 ) evolution is at the cutting edge because of the higher gravimetric energy density of H 2 fuel. , Overall water splitting (OWS) can be regarded as an environmentally viable technique as it promises the non-hazardous conversion of H 2 experimentally, − which is also supported by computational perspectives . Ever since the visionary research of Fujishima and Honda for the H 2 generation via water splitting using a TiO 2 semiconductor, extensive research has been carried out in this area in order to upgrade and optimize the catalytic systems, which would produce H 2 efficiently in visible-light irradiation .…”

“…Perovskite materials such as GdCrO 3 , TbFeO 3 , SrTiO 3 , NaNbO 3 , and DyCrO 3 have been widely studied for their application in photocatalytic H 2 generation. ,− SrTiO 3 is an n -type photocatalyst with a band gap of ∼3.2 eV lying in the UV–visible region. However, with slight chemical and compositional modifications, SrTiO 3 has shown excellent improvement in its photocatalytic efficiency in the visible-light region.…”