Co2B and Co Nanoparticles Immobilized on the N-B-Doped Carbon Derived from Nano-B4C for Efficient Catalysis of Oxygen Evolution, Hydrogen Evolution, and Oxygen Reduction Reactions

Heterogeneous Ni-Boride/Phosphide Anchored Amorphous B-C Layer for Overall Water Electrocatalysis

The rational design of efficient and economical bifunctional electrocatalysts remained a challenge for overall water electrolysis. In this work, the Ni-boride/ phosphide particles anchored amorphous B-doped carbon layer with hierarchical porous characteristics in Ni foam (Ni3P/Ni3B/B-C/NF) was fabricated for overall water splitting. The Boroncarbide (B4C) power was filled and fixed in the NF interspace through the electroplating and electroless plating, and then annealed in vacuum high temperature. The amorphous B-C layer derived from the B4 C not only speeded up the electron transport, but also cooperate with Ni-boride/phosphide to enhance the electrocatalytic activity for HER and OER synergistically. Furthermore, the hierarchical porous architecture of Ni3P/Ni3B/B-C/NF increased space utilization to load more active materials. The self-supported Ni3P/Ni3B/B-C/NF electrode possessed a low overpotential of 212 and 280 mV to deliver 100 mA cm-2 for HER and OER, respectively, and high stability for 48 h. In particular, the electrolyzer constituted with the Ni3P/Ni3B/B-C/NF bifunctional electrocatalyst only required a voltage of 1.59 V at 50 mA cm-2 for water electrocatalysis under alkaline medium, and demonstrated long-term stability for 48 h. This study provides a new technical path for the development of bifunctional of transition metal borides to promote the application of hydrogen production from water splitting.

Superhydrophilicity boron-doped cobalt phosphide nanosheets decorated carbon nanotube arrays self-supported electrode for overall water splitting

Transition metal borides (TMBs) or phosphides (TMPs) have attracted great attention to the design of bifunctional electrocatalysts for energy storage. The superaerophobicity and superhydrophilicity of the catalytic electrode surface are crucial factors to determine the reaction process of the gas electrode. Herein, we report a self-supported electrode of carbon nanotube (CNTs) array grown on carbon cloth (CC) modulated together by boron-doped cobalt phosphide (CoP-B/CNTs/CC). The electrode requires the overpotential of 73.8 mV and 189.5 mV at the current density of ±10 mA cm-2 for hydrogen and oxygen evolution reactions in an alkaline electrolyte (1.0 M KOH), respectively, meanwhile maintaining outstanding long-term durability for more than 300 h. The excellent activity of CoP-B/CNTs/CC is attributed to boron doping regulating its electronic structure and further enriching active sites. The attractive stability of CoP-B/CNTs/CC is due to the unique geometric structure of the self-supported electrode. Furthermore, the superaerophobicity and superhydrophilicity of the electrode surface also accelerate the reaction process of the gas electrode. Expectedly, water splitting cells assembled using CoP-B/CNTs/CC electrodes as cathode and anode, respectively, require a cell voltage of 1.54 V at 10 mA cm-2, which is lower than that of the Pt/C/CC||RuO2/CC couple (1.69 V at 10 mA cm-2). Importantly, CoP-B/CNTs/CC||CoP-B/CNTs/CC achieve stable cell voltage under the step current changes (10 mA cm-2, 50 mA cm-2, and 100 mA cm-2) over 300 h. This work highlights a new path to understanding the effects of the static and dynamic behavior of bubbles on the surface of self-supporting electrodes on catalytic performance.

In Vitro Transcriptome Analysis of Cobalt Boride Nanoparticles on Human Pulmonary Alveolar Cells

Nanobiotechnology influences many different areas, including the medical, food, energy, clothing, and cosmetics industries. Considering the wide usage of nanomaterials, it is necessary to investigate the toxicity potentials of specific nanosized molecules. Boron-containing nanoparticles (NPs) are attracting much interest from scientists due to their unique physicochemical properties. However, there is limited information concerning the toxicity of boron-containing NPs, including cobalt boride (Co₂B) NPs. Therefore, in this study, Co₂B NPs were characterized using X-ray crystallography (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) techniques. Then, we performed 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH) release, and neutral red (NR) assays for assessing cell viability against Co₂B NP exposure on cultured human pulmonary alveolar epithelial cells (HPAEpiC). In addition, whole-genome microarray analysis was carried out to reveal the global gene expression differentiation of HPAEpiC cells after Co₂B NP application. The cell viability tests unveiled an IC50 value for Co₂B NPs of 310.353 mg/L. The results of our microarray analysis displayed 719 gene expression differentiations (FC ≥ 2) among the analyzed 40,000 genes. The performed visualization and integrated discovery (DAVID) analysis revealed that there were interactions between various gene pathways and administration of the NPs. Based on gene ontology biological processes analysis, we found that the P53 signaling pathway, cell cycle, and cancer-affecting genes were mostly affected by the Co₂B NPs. In conclusion, we suggested that Co₂B NPs would be a safe and effective nanomolecule for industrial applications, particularly for medical purposes.

A New Photoelectrocatalyst for Water Oxidation: A Polyoxometalate-Graphitic Carbon Nitride Hybrid Nanomaterial

A new photoelectrocatalyst for the water oxidation process is designed by immobilizing [CoW₁₂O₄₀]^6- (CoW₁₂) heteropolyanions on the surface of covalently modified graphitic carbon nitride nanosheets (g-C₃N₄). For this purpose, g-C₃N₄ is first modified with cysteamine hydrochloride through the well-known thiol-ene click reaction. Afterward, [CoW₁₂O₄₀]^6- heteropolyanions are immobilized on the surface of modified g-C₃N₄ nanosheets with electrostatic interaction with ammonium groups. After confirming the preparation of CoW₁₂/clicked g-C₃N₄ with various physicochemical methods, its photoelectrocatalytic activity is evaluated in the oxygen evolution reaction. The CoW₁₂/clicked g-C₃N₄ exhibits a low onset potential of 1.32 V versus NHE and a low overpotential of 230 mV at 10 mA cm^-2 with a low Tafel slope of 67 mV dec^-1 under visible light illumination. Moreover, the stability of the catalyst is investigated through the chronoamperometric measurements.

Flower-like Co3Ni1B nanosheets based on reduced graphene oxide (rGO) as an efficient electrocatalyst for the oxygen evolution reaction

Flower-like Co3Ni1B nanosheets based on a reduced graphene oxide electrocatalyst exhibit a better OER performance than commercial RuO2.

Nickel Boride/Boron Carbide Particles Embedded in Boron-Doped Phenolic Resin-Derived Carbon Coating on Nickel Foam for Oxygen Evolution Catalysis in Water and Seawater Splitting

Electrolysis of seawater can be a promising technology, but chloride ions in seawater can lead to adverse side reactions and the corrosion of electrodes. A new transition metal boride-based self-supported electrocatalyst was prepared for efficient seawater electrolysis by directly soaking nickel foam (NF) in a mixture of phenolic resin (PR) and boron carbide (B₄ C), followed by an 800 °C annealing. During PR carbonization process, the reaction of B₄ C and NF generated nickel boride (Ni_x B) with high catalytic activity, while PR-derived carbon coating was doped with boron atoms from B₄ C (B-C_PR ). The B-C_PR coating fixed Ni_x B/B₄ C particles in the frames and holes to improve the space utilization of NF. Meanwhile, the B-C_PR coating effectively protected the catalyst from the corrosion by seawater and facilitates the transport of electrons. The optimal Ni_x B/B₄ C/B-C_PR /NF required 1.50 and 1.58 V to deliver 100 and 500 mA cm^-2 , respectively, in alkaline natural seawater for the oxygen evolution reaction.

Noble-Metal-Free Multicomponent Nanointegration for Sustainable Energy Conversion

Global energy and environmental crises are among the most pressing challenges facing humankind. To overcome these challenges, recent years have seen an upsurge of interest in the development and production of renewable chemical fuels as alternatives to the nonrenewable and high-polluting fossil fuels. Photocatalysis, photoelectrocatalysis, and electrocatalysis provide promising avenues for sustainable energy conversion. Single- and dual-component catalytic systems based on nanomaterials have been intensively studied for decades, but their intrinsic weaknesses hamper their practical applications. Multicomponent nanomaterial-based systems, consisting of three or more components with at least one component in the nanoscale, have recently emerged. The multiple components are integrated together to create synergistic effects and hence overcome the limitation for outperformance. Such higher-efficiency systems based on nanomaterials will potentially bring an additional benefit in balance-of-system costs if they exclude the use of noble metals, considering the expense and sustainability. It is therefore timely to review the research in this field, providing guidance in the development of noble-metal-free multicomponent nanointegration for sustainable energy conversion. In this work, we first recall the fundamentals of catalysis by nanomaterials, multicomponent nanointegration, and reactor configuration for water splitting, CO₂ reduction, and N₂ reduction. We then systematically review and discuss recent advances in multicomponent-based photocatalytic, photoelectrochemical, and electrochemical systems based on nanomaterials. On the basis of these systems, we further laterally evaluate different multicomponent integration strategies and highlight their impacts on catalytic activity, performance stability, and product selectivity. Finally, we provide conclusions and future prospects for multicomponent nanointegration. This work offers comprehensive insights into the development of cost-competitive multicomponent nanomaterial-based systems for sustainable energy-conversion technologies and assists researchers working toward addressing the global challenges in energy and the environment.

Double-shelled carbon nanocages grafted with carbon nanotubes embedding Co nanoparticles for enhanced hydrogen evolution electrocatalysis

Herein, small Co nanoparticles (NPs) encapsulated in N-doped double-shelled carbon nanocages grafted with thin carbon nanotubes (Co@CNTs@DSCNCs) were synthesized from yolk-shell bimetallic zeolitic imidazolate framework (BMZIF). For HER electrocatalysis, they exhibit higher activity (η₁₀ = 214 mV) and more favorable kinetics than Co@CNTs@PC (PC = porous carbon) with thick CNTs and large Co NPs derived from solid BMZIF cubes.