Electrocatalytic overall water splitting based on (ZnNiCoFeY)xOy high-entropy oxide supported on MoS2

Hydrogen energy is a sustainable and clean source that can meet global energy demands without adverse environmental impacts. High-entropy oxides (HEOs), multielement (5 or more) oxides with an equiatomic or near-equatomic elemental composition, offer a novel approach to designing bifunctional electrocatalysts. This work explores (ZnNiCoFeY)xOy over MoS2 as a bifunctional electrocatalyst (HEO–MoS2) in an alkaline medium. The HEO was synthesized using a combustion process and loaded over MoS2 using an ultrasonic method. The synthesized HEO over MoS2 exhibits excellent performance, including long-term stability for over 24 h, an overpotential of 214 mV vs the reversible hydrogen electrode (RHE) for the hydrogen evolution reaction (HER), and 308 mV for the oxygen evolution reaction (OER) at 10 mA cm−2. This bifunctional electrocatalyst exhibits low overpotential for both the HER and the OER at high current densities. Additionally, HEO–MoS2 demonstrates smaller solution and charge transfer resistance values. The electrolyzer was assembled using bifunctional HEO–MoS2 electrodes for overall water splitting. These electrodes exhibited a low cell voltage of 1.65 V at 10 mA cm−2. The novel electrocatalyst was fabricated using a facile and scalable method that appeals to industrial applications

First-Principles Density Functional Theory and Machine Learning Technique for the Prediction of Water Adsorption Site on PtPd-Based High-Entropy-Alloy Catalysts

The water-gas shift reaction (WGSR) is employed in industry to obtain high-purity H-2 from syngas, where H2O adsorption is an important step that controls H2O dissociation in WGSR. Therefore, exploring catalysts exhibiting strong H2O adsorption energy (E-ads) is crucial. Also, high-entropy alloys (HEA) are promising materials utilized as catalysts, including in WGSR. The PtPd-based HEA catalysts are explored via density functional theory (DFT) and Gaussian process regression. The input features are based on the microstructure data and electronic properties: d-band center (epsilon(d)) and Bader net atomic charge (delta). The DFT calculation reveals that the epsilon(d) and delta of each active site of all HEA surfaces are broadly scattered, indicating that the electronic properties of each atom on HEA are non-uniform and influenced by neighboring atoms. The strong H2O-active-site interaction determined by a highly negative E-ads is used as a criterion to explore good PtPd-based WGSR catalyst candidates. As a result, the potential candidates are found to have Co, Ru, and Fe as an H2O adsorption site with Ag as a neighboring atom, that is, PtPdRhAgCo, PtPdRuAgCo, PtPdRhAgFe, and PtPdRuAgFe.Funding Agencies|Second Century Fund (C2F); Thailand Science Research and Innovation Fund Chulalongkorn University [CU_FRB65_ind (15)_163_21_29, IND66210011]; Research Grants for Talented Young Researchers, National Research Council of Thailand 2022; National Science and Technology Development Agency, Thailand; Asahi Glass Foundation; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University, Faculty Grant SFOMatLiU [2009 00971]; Swedish Foundation for Strategic Research through the Future Research Leaders 6 program [FFL 15-0290]; Swedish Research Council (VR) [2019-05403]; Knut and Alice Wallenberg Foundation, Sweden (Wallenberg Scholar Grant) [KAW-2018.0194]; Swedish Research Council, Sweden [2018-05973]; NSTDA Supercomputer Center (ThaiSC), Thailand</p

Experimental and first-principles insights into an enhanced performance of Ru-doped copper phosphate electrocatalyst during oxygen evolution reaction

The oxygen evolution reaction (OER) is a vital half-reaction in many applications, such as the electrochemical H2O splitting, CO2, and N2 conversion processes. The OER involves a four-electron transfer and is a kinetically sluggish reaction that requires additional potential to drive. To enhance the electrochemical performance of the above-mentioned applications, highly efficient, corrosion-resistant, earth-abundant, and eco-friendly electrocatalysts are required. Here, we report a highly porous, minimally Ru-doped copper phosphate electrocatalyst obtained through co-precipitation. The optimized electrocatalyst (5% Ru-doped copper phosphate) exhibits a low overpotential of 340 mV to achieve 10 mA cm−2 compared to copper-based materials, and it remains stable over 20 h. The high performance is attributed to a high electrochemically effective surface area (ECSA) of 30.25 cm2, facilitating effective ion transportation at the electrode/electrolyte interface and excellent electrical conductivity. This result is supported by density functional theory calculations, which demonstrate that ruthenium enhances the electrochemical properties by increasing electronic conductivity, reducing the theoretical overpotential, and influencing the rate-determining step of the oxygen evolution reaction. Herein, the electrocatalyst is attractive for commercialization due to its utilization of minimal ruthenium in earth-abundant electrocatalysts, which offer competitive performance

Electrocatalytic overall water splitting based on (ZnNiCoFeY)xOy high-entropy oxide supported on MoS2

Hydrogen energy is a sustainable and clean source that can meet global energy demands without adverse environmental impacts. High-entropy oxides (HEOs), multielement (5 or more) oxides with an equiatomic or near-equatomic elemental composition, offer a novel approach to designing bifunctional electrocatalysts. This work explores (ZnNiCoFeY)xOy over MoS2 as a bifunctional electrocatalyst (HEO–MoS2) in an alkaline medium. The HEO was synthesized using a combustion process and loaded over MoS2 using an ultrasonic method. The synthesized HEO over MoS2 exhibits excellent performance, including long-term stability for over 24 h, an overpotential of 214 mV vs the reversible hydrogen electrode (RHE) for the hydrogen evolution reaction (HER), and 308 mV for the oxygen evolution reaction (OER) at 10 mA cm−2. This bifunctional electrocatalyst exhibits low overpotential for both the HER and the OER at high current densities. Additionally, HEO–MoS2 demonstrates smaller solution and charge transfer resistance values. The electrolyzer was assembled using bifunctional HEO–MoS2 electrodes for overall water splitting. These electrodes exhibited a low cell voltage of 1.65 V at 10 mA cm−2. The novel electrocatalyst was fabricated using a facile and scalable method that appeals to industrial applications