Despite global efforts to reduce the use of fossil fuels, carbon dioxide (CO2) emissions continue to rise. As the demand for clean energy grows, hydrogen (H2), which does not emit CO2 during combustion, is emerging as a promising energy resource. Among the various hydrogen production technologies, water electrolysis is attracting attention as a method for producing green hydrogen without carbon emissions. However, its high reaction overpotentials, due to complex reaction pathways, are a major factor limiting its energy efficiency. To address these issues, chemical-assisted water electrolysis is considered as an innovative alternative. This technology enables hydrogen production at lower voltages. Moreover, it can generate high-value products and remove pollutants, providing both environmental and energy benefits. In this review, we introduce various types of chemical-assisted water electrolysis and discuss the latest advances in catalyst design and reaction mechanisms aimed at reducing applied system voltage. Finally, we address the main challenges and prospects of chemical-assisted water electrolysis.
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The increasing importance of high-purity isopropyl alcohol (IPA) in semiconductor processing technology has led to a higher demand for technologies capable of detecting impurities in IPA. Although accurate and various impurity detection technologies have been developed, most of them have limitations in real-time and repeatable detection of impurities. Herein, for the first time, surface plasmon resonance (SPR) sensor was developed utilizing graphene transferred Au film (Au/graphene) to detect sub-ppm levels of 2,4-dinitrophenol (2,4-DNP) dissolved in IPA and this sensor demonstrates the ability to detect 2,4-DNP in real-time with great reversibility. The adsorption of 2,4-DNP to graphene is found to be stronger than that for Au film because of noncovalent graphene π–π stacking interaction, and the effect of graphene is demonstrated through density function theory (DFT) calculations and enhancement in sensing performance of Au/graphene sensor. Additionally, the presence of noncovalent π–π stacking interaction between 2,4-DNP and graphene has been demonstrated by confirming the p-doping effect of graphene-based solution field-effect transistor measurements and consecutive Raman spectra analysis. This study offers experimental and theoretical insights into the adsorption kinetics of 2,4-DNP dissolved in IPA and provides promising perspectives for real-time sensing technology utilizing label-free graphene to detect impurities in high-purity cleaning agents.
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Here we introduce bismuth-based catalysts for the efficient electrochemical reduction of CO2 to formic acid (HCOOH), which are composed of petal-shaped Bi2O2CO3 (BOC) that spontaneously formed from Bi thin film in aqueous carbonate solution at room temperature. During the electrochemical reduction process, the BOC petals transform to reduced BOC (R-BOC) consisting of individual BOC and Bi domains. Lattice mismatch between both domains induces biaxial strain at the interfaces. Density functional theory calculations suggest that the tensile strain on the Bi domain stabilizes the *OCHO intermediate, reducing the thermodynamic barrier toward CO2 conversion to HCOOH. Together with the thermodynamic benefit and the unique nanoporous petal-shaped morphology, R-BOC petals have a superior Faradaic efficiency of 95.9% at −0.8 VRHE for the electrochemical conversion of CO2 to HCOOH. This work demonstrates that the spontaneously formed binary phases with desirable lattice strain can increase the activity of bismuth catalysts to the CO2 reduction reaction; such a strategy can be applicable in design of various electrocatalysts.
In photoelectrochemical (PEC) water splitting, charge separation and collection by the electric field in the photoactive material are the most important factors for improved conversion efficiency. Hence, ferroelectric oxides, in which electrons are the majority carriers, are considered promising photoanode materials because their high built-in potential, provided by their spontaneous polarization, can significantly enhance the separation and drift of photogenerated carriers. In this regard, the PEC properties of BiFeO3 thin-film photoanodes with different crystallographic orientations and consequent ferroelectric domain structures are investigated. As the crystallographic orientation changes from (001)pc via (110)pc to (111)pc, the ferroelastic domains in epitaxial BiFeO3 thin films become mono-variant and the spontaneous polarization levels increase to 110 μC/cm2. Consequently, the photocurrent density at 0 V vs. Ag/AgCl increases approximately 5.3-fold and the onset potential decreases by 0.180 V in the downward polarization state. It is further demonstrated that ferroelectric switching in the (111)pc BiFeO3 thin-film photoanode leads to an approximate change of 8, 000% in the photocurrent density and a 0.330 V shift in the onset potential. This study strongly suggests that domain-engineered ferroelectric materials can be used as effective charge separation and collection layers for efficient solar water-splitting photoanodes.
We present a facile method for producing superhydrophobic nanograss-coated (SNGC) glass surfaces that possess both reduced reflectivity and self-cleaning properties at the air/glass interface. The refractive index of a CaF2 nanograss (NG) layer on a glass substrate, deposited by glancing angle vapor deposition, is 1.04 at 500 nm, which is the second-lowest value ever reported so far. The fluorinated NG layer gives rise to a high water contact angle (> 150°) and very efficient cleaning out of dust with water drops. Using the dual functionalities of the SNGC glass, we demonstrate superhydrophobic and antireflective organic photovoltaic cells with excellent power conversion efficiency.
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