Metal oxides supported cobalt nanoparticles: Active electrocatalysts for oxygen evolution reaction

Enhance Water Electrolysis for Green Hydrogen Production with Material Engineering: A Review

Water electrolysis, a traditional and highly technology, is gaining significant attention due to the growing demand for renewable energy resources. It stands as a promising solution for energy conversion, offer substantial benefits in environmental protection and sustainable development efforts. The aim of this research is to provide a concise review of the current state-of-the-art in the field of water electrolysis, focusing on the principles of water splitting fundamental, recent advancements in catalytic materials, various advanced characterization methods and emerging electrolysis technology improvements. Moreover, the paper delves into the development trends of catalysts engineering for water electrolysis, providing insight on how to enhance the catalytic performance. With the advancement of technology and the reduction of costs, hydrogen production through water electrolysis is expected to assume a more significant role in future energy ecosystem. This paper not only synthesizes existing knowledge but also highlights emerging opportunities and potential advancements in this field, offering a clear roadmap for further research and innovation.

The support effect on the performance of a MOF-derived Co-based nano-catalyst in Fischer Tropsch synthesis

The catalyst plays a central role in the Fischer-Tropsch synthesis (FTS) process, and the choice of catalyst support significantly impacts FTS catalyst performance by enhancing its attributes. In this study, the effects of utilizing various metal oxides-CeO2, ZrO2, and TiO2-on a cobalt-based FTS nanocatalyst are investigated by evaluating the catalyst's reducibility, stability, syngas chemisorption, intermediate species spillover, charge transfer, and metal-support interaction (MSI). This evaluation is conducted both theoretically and experimentally through diverse characterization tests and molecular dynamics (MD) simulations. Characterization tests reveal that the ceria-supported catalyst (Ceria Nano Catalyst, CNC) demonstrates the highest reducibility, stability, CO chemisorption, and spillover, while the zirconia-supported catalyst (Zirconia Nano Catalyst, ZNC) exhibits the highest hydrogen chemisorption and spillover. The MD simulation results align well with these findings; for instance, ZNC has the lowest hydrogen adsorption enthalpy (ΔHAds.), whereas CNC has the lowest ΔHAds. for CO. Additionally, MD simulations indicate that the titania-supported catalyst (Titania Nano Catalyst, TNC) possesses the highest MSI value, closely resembling that of ZNC, albeit with a minor difference. The TNC catalyst's performance in other tests is also similar to that of ZNC. Finally, FTS performance tests illustrate that the ZNC catalyst achieves the highest CO conversion at 88.1%, while the CNC catalyst presents the lowest CO conversion at 82.2%. Notably, the CNC catalyst showcases the highest durability, with only a 4.4% loss in CO conversion and an 8.55% loss in C5+ yield after 192 h of operation.

High-Entropy La(FeCuMnMgTi)O3 Nanoparticles as Heterogeneous Catalyst for CO2 Electroreduction Reaction

In this work, La(FeCuMnMgTi)O3 HEO nanoparticles with a perovskite-type structure are synthesized and used in the electrocatalytic CO2 reduction reaction (CO2RR). The catalyst demonstrates high performance as an electrocatalyst for the CO2RR, with a Faradaic efficiency (FE) of 92.5% at a current density of 21.9 mA cm-2 under -0.75 V vs a saturated calomel electrode (SCE). Particularly, an FE above 54% is obtained for methyl isopropyl ketone (C5H10O, MIPK) at a partial current density of 16 mA cm-2, overcoming all previous works. Besides, the as-prepared HEO catalyst displays robust stability in the CO2RR. The excellent catalytic performance of La(FeCuMnMgTi)O3 is ascribed to the synergistic effect between the electronic effects associated with five cations occupying the high-entropy sublattice sites and the oxygen vacancies within the perovskite structure of the HEO. Finally, DFT calculations indicate that Cu plays a vital role in the catalytic activity of the La(FeCuMnMgTi)O3 HEO nanoparticles toward C2+ products.

Hollow CoVOx/Ag nanoprism with tailored electronic structure for high efficiency oxygen evolution reaction

Developing high-active and inexpensive electrocatalysts for oxygen evolution reaction (OER) is very important in the field of water splitting. The catalytic performance of electrocatalysts can be significantly improved by optimizing the electronic structure and designing suitable nanostructure. In this work, we represent the synthesis of hollow CoVOx/Ag-5 for OER. Due to the interaction of CoVOx and Ag nanoparticles, the electronic structure is optimized to improve the intrinsic catalytic activity. Additionally, the extrinsic catalytic activity of CoVOx/Ag is enhanced by the abundant active sites from the hollow structure. As a result, the CoVOx/Ag-5 demonstrates significantly enhanced OER catalytic activity with a low overpotential of 247 mV at 10 mA cm-2. In addition, it also exhibits excellent durability, without obvious attenuation in performance after continuous operation for 60 h. Furthermore, the catalyst can enable full water splitting with appropriate 100 % Faraday efficiency, demonstrating its practical application.

Metal oxide stabilized zirconia modified bio-derived carbon nanosheets as efficient electrocatalysts for oxygen evolution reaction.. [DOI: 10.21203/rs.3.rs-2708309/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Zirconia is a promising candidate for many applications, especially when stabilized with metal oxide nanoparticles such as yttria and ceria. Zirconium oxide-based materials supported on carbon nanomaterials have shown excellent performance electrocatalysts due to their outstanding catalytic activities and high stability. In this work, a one-pot hydrothermal method was used to prepare porous stabilized zirconia nanoparticles with yttria and ceria (YSZ and CSZ) anchored on carbon nanosheets derived from molasses fiber waste as a sustainable source and annealing at various temperatures (MCNSs). The prepared composites YSZ/MCNSs and CSZ/MCNSs exhibit superior oxygen evolution reaction (OER) performance in alkaline medium. Various physicochemical analysis techniques such as SEM, EDX, HR-TEM, XRD and XPS are employed to characterize the designed catalysts. The results showed that the doping of molasses fibers exfoliated into 2D nanosheets controlled the growth of the YSZ particles into the nanosize and increased their crystallinity. This improves the electrochemical surface area (ECSA) and stability, and modulates the electronic structure of zirconium, yttrium and cerium which facilitate the adsorption of OH- ions, and all contribute to the higher catalytic activity.

CoMo layered double hydroxide equipped with carbon nanotubes for electrocatalytic oxygen evolution reaction

To carry out effective resource reforming of sustainable electricity, hydrogen production by electrochemical water splitting provides an eco-friendly and economical way. Nevertheless, the oxygen evolution reaction (OER) at the anode is limited by the slow reaction process, which hinders the large-scale development and application of electrolysis technology. In this work, we present an electrocatalyst with superior OER performance, which attributed to the abundant active sites and good electronic conductivity. The two-dimensional CoMo Layered Double Hydroxide nanosheets are synthesized and deposited on conductive carbon nanotubes (CoMo LDH/CNTs), and then hybrid composites show better catalytic performance than their undecorated counterpart under identical conditions. Specifically, CoMo LDH/CNTs exhibit the low overpotential of 268 mV to obtain 10 mA cm^-2and satisfactory stability (more than 40 h). We emphasize that this hybridization strategy with a conductive supporting framework could design more abundant and low-cost OER electrocatalysts to minimize electrical energy consumption, thereby achieving efficient conversion between energy sources.

Phytochemical-Assisted Green Synthesis of Nickel Oxide Nanoparticles for Application as Electrocatalysts in Oxygen Evolution Reaction

Electrocatalytic water splitting is a promising solution to resolve the global energy crisis. Tuning the morphology and particle size is a crucial aspect in designing a highly efficient nanomaterials-based electrocatalyst for water splitting. Herein, green synthesis of nickel oxide nanoparticles using phytochemicals from three different sources was employed to synthesize nickel oxide nanoparticles (NiOx NPs). Nickel (II) acetate tetrahydrate was reacted in presence of aloe vera leaves extract, papaya peel extract and dragon fruit peel extract, respectively, and the physicochemical properties of the biosynthesized NPs were compared to sodium hydroxide (NaOH)-mediated NiOx. Based on the average particle size calculation from Scherrer’s equation, using X-ray diffractograms and field-emission scanning electron microscope analysis revealed that all three biosynthesized NiOx NPs have smaller particle size than that synthesized using the base. Aloe-vera-mediated NiOx NPs exhibited the best electrocatalytic performance with an overpotential of 413 mV at 10 mA cm−2 and a Tafel slope of 95 mV dec−1. Electrochemical surface area (ECSA) measurement and electrochemical impedance spectroscopic analysis verified that the high surface area, efficient charge-transfer kinetics and higher conductivity of aloe-vera-mediated NiOx NPs contribute to its low overpotential values.