Adsorption Free Energy of Glycine on TiO2 in Water from First Principles Simulations and Electrochemical Impedance Spectroscopy

The adhesion of amino acids and small organic molecules on TiO2 nanoparticles is fundamental for bio-nano functionalization of peptides and proteins. The adsorption free energy is the main physical quantity that regulates the adsorption process. Its evaluation is particularly challenging both experimentally, due to the weak interfacial signal in aqueous environments, and by atomistic simulations, due to the complexity of the physical phenomena occurring at the solid-water interface (polarization and charge transfer effects). We report here an accurate experimental-computational study of hydrated TiO2 nanoparticles interacting with Glycine where we obtain quantitative agreement of the measured adsorption free energy. Ab-initio simulations are performed within the Tight Binding Density Functional Theory in combination with enhanced free energy sampling techniques. The experiments adopt a new and efficient set-up for electrochemical impedance spectroscopy measurements based on screen-printed gold electrodes. The measured adsorption free energy is about -30 kJ/mol (both from experiment and calculation), with preferential interaction of the charged NH3 group which strongly adsorbs on the TiO2 bridging oxygens. The perfect agreement between computation and experiment opens the doors to an extended exploration of the bio-nano interaction for different materials and molecules.

MoS2 with Controlled Thickness for Electrocatalytic Hydrogen Evolution

Molybdenum disulfide (MoS2) has moderate hydrogen adsorption free energy, making it an excellent alternative to replace noble metals as hydrogen evolution reaction (HER) catalysts. The thickness of MoS2 can affect its energy band structure and interface engineering, which are the avenue way to adjust HER performance. In this work, MoS2 films with different thicknesses were directly grown on the glassy carbon (GC) substrate by atomic layer deposition (ALD). The thickness of the MoS2 films can be precisely controlled by regulating the number of ALD cycles. The prepared MoS2/GC was directly used as the HER catalyst without a binder. The experimental results show that MoS2 with 200-ALD cycles (the thickness of 14.9 nm) has the best HER performance. Excessive thickness of MoS2 films not only lead to the aggregation of dense MoS2 nanosheets, resulting in reduction of active sites, but also lead to the increase of electrical resistance, reducing the electron transfer rate. MoS2 grown layer by layer on the substrate by ALD technology also significantly improves the bonding force between MoS2 and the substrate, showing excellent HER stability.

The Inhibition Action of Viscum Album Extract on theCorrosion of Carbon Steel in Hydrochloric Acid Solution

Corrosion rate of carbon steel (CS) in 1M HCl was examined in the absence and presence of Viscum album plant extract as a corrosion inhibitor using weight loss, polarization, and impedance techniques. The effect of temperature and extract dose was studied using a weight loss test. The outcome data gained displayed that Viscum album extract plays as an inhibitor for CS in HCl and reduces the corrosion rate. The higher inhibition efficacy reached 96.3% for Viscum album at greater inhibitor doses (300 ppm) and temperature. Polarization data revealed that this extract acts as a mixed kind inhibitor. The surface analysis of CS was checked by different methods, which showed the formation of extract film on the CS surface. The adsorption of Viscum album plant extract was found to obey the Temkin model, and the data of adsorption free energy was more negative than -40 kJ/mol, which means that the adsorption is chemical.

(002) facets exposed and controllable thickness of CdS nanobelts drive desirable hydrogen-adsorption free energy (△GH) for boosting visible-light photocatalytic performance

In order to obtain the high photocatalytic performance, co-catalysts loading is the most commonly used, which is economically disadvantaged and environmental pollution. Here, we combine the strategy of controllable thickness...

Cobalt phosphide supported by two-dimensional molybdenum carbide (MXene) for the hydrogen evolution reaction, oxygen evolution reaction, and overall water splitting

CoP/Mo2CTx is prepared as efficient catalyst for HER, OER, and water splitting. DFT calculations revealed that it has optimal H* adsorption free energy and MXene plays a critical role to boost HER, while CoP is transformed into Co–OOH in OER.

Industry-applicable, efficient hydrogen evolution reaction through an interface-activated bimetallic electrode with seawater photolysis in alkaline media

<p><a><b>Hydrogen evolution reaction (HER) electrocatalysts over platinum (Pt) in an alkaline medium is crucial for hydrogen economy. Herein, we demonstrate new concept “interface-active electrode” to transform naturally inert alkaline HER materials towards industry-applicable HER electrocatalyst, comprised of interface-rich NiP₂-FeP₂ on Cu nanowires that required overpotential as low as 23.6 and 357 mV at -10 and -1000 mA/cm², respectively, with exceptional stability at the industrial current density of -1 A cm^-2, superior to commercial Pt under alkaline solution. Structural characterization and theoretical calculations revealed the abundant interface between facets of NiP₂-FeP₂on Cu exhibits optimum H adsorption-free energy than Pt and lower kinetic barrier for water dissociation (Δ<i>G</i>_B = 0.16 eV), boosting alkaline HER. Additionally, when integrated in a water splitting device, generated 10 mA/cm²at only </b></a><b>1.42, 1.4, and 1.31 V </b><b>under 1 M KOH, artificial seawater at 25 ̊C and 100 ̊C, respectively, along with high solar-to-hydrogen (STH) conversion efficiency of 19.85</b><b> %. </b></p>

Industry-applicable, efficient hydrogen evolution reaction through an interface-activated bimetallic electrode with seawater photolysis in alkaline media

<p><a><b>Hydrogen evolution reaction (HER) electrocatalysts over platinum (Pt) in an alkaline medium is crucial for hydrogen economy. Herein, we demonstrate new concept “interface-active electrode” to transform naturally inert alkaline HER materials towards industry-applicable HER electrocatalyst, comprised of interface-rich NiP₂-FeP₂ on Cu nanowires that required overpotential as low as 23.6 and 357 mV at -10 and -1000 mA/cm², respectively, with exceptional stability at the industrial current density of -1 A cm^-2, superior to commercial Pt under alkaline solution. Structural characterization and theoretical calculations revealed the abundant interface between facets of NiP₂-FeP₂on Cu exhibits optimum H adsorption-free energy than Pt and lower kinetic barrier for water dissociation (Δ<i>G</i>_B = 0.16 eV), boosting alkaline HER. Additionally, when integrated in a water splitting device, generated 10 mA/cm²at only </b></a><b>1.42, 1.4, and 1.31 V </b><b>under 1 M KOH, artificial seawater at 25 ̊C and 100 ̊C, respectively, along with high solar-to-hydrogen (STH) conversion efficiency of 19.85</b><b> %. </b></p>