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12 pages, 1980 KB

Open AccessArticle

Correlating Boron Existence Morphologies with Electrocatalytic HER Activity in Ni-B Compounds Synthesized via High Pressure and High Temperature

by Xinrong Guo, Rui Bao, Jiawen Lv, Li Bai, Guiqian Sun, Huilian Liu, Pinwen Zhu, Yanli Chen, Maobin Wei and Qiang Tao

Catalysts 2026, 16(1), 65; https://doi.org/10.3390/catal16010065 - 6 Jan 2026

Cited by 1 | Viewed by 680

Abstract

Nickel boride compounds have attracted considerable attention in the field of electrocatalysis due to their unique electronic structures and excellent chemical stability. However, the difficulty in obtaining single-phase products under traditional experimental conditions hinders the analysis of their intrinsic catalytic performance. Herein, we report the successful synthesis of three single-phase nickel boride compounds (Ni₂B, Ni₄B₃, and NiB) via a high pressure and high temperature (HPHT) method. The configurations of B in their respective structures are distinct. Their electrocatalytic hydrogen evolution reaction (HER) performance was systematically evaluated. The results demonstrate that NiB exhibits the lowest overpotentials of 182 mV (in acidic electrolyte) and 234 mV (in alkaline electrolyte) at a current density of 10 mA cm⁻², accompanied by the smallest Tafel slope, the lowest electron transfer resistance (R_ct), and the largest double-layer capacitance (C_dl). This superior HER activity is primarily attributed to the presence of strong B-B covalent bonds in NiB, which weaken the Ni-B interaction and reduce the orbital hybridization between Ni 3d and B 2p orbitals. Consequently, the hydrogen adsorption intermediate (H*) achieves the optimal adsorption strength on the NiB surface. This work provides a novel insight for the design of high-performance transition metal boride electrocatalysts. Full article

(This article belongs to the Special Issue 15th Anniversary of Catalysts: Feature Papers in Electrocatalysis)

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10 pages, 2895 KB

Open AccessCommunication

Amorphous Co-NiB@NF as an Efficient Electrocatalyst for Urea Oxidation Reaction

by Shuai Geng, Bo Hai and Heping Shi

Catalysts 2025, 15(7), 612; https://doi.org/10.3390/catal15070612 - 21 Jun 2025

Viewed by 1388

Abstract

Transition metal-based catalysts designed for efficient urea oxidation reactions (UOR) are essential for hydrogen production via urea-assisted water electrolysis. A series of amorphous nickel–cobalt boride catalysts supported on nickel foam were in situ synthesized via a stepwise chemical deposition method (SCDM). The systematic investigation focused on the relationships between synthesis parameters (deposition cycles, reactant feed ratio), morphological characteristics, and UOR performance. Notably, the optimized Co-NiB@NF catalyst exhibits a porous hierarchical architecture composed of metallic nanoparticles encapsulated by surface-wrinkled nanosheets, forming abundant exposed active sites. Electrochemical measurements demonstrate that this catalyst requires a low cell potential of 1.29 V to achieve a current density of 10 mA cm⁻². Moreover, it maintains 83% of the initial current density after 10 h of continuous electrolysis, highlighting its superior durability. The structural-property relationship revealed here provides valuable insights into the rational design of efficient amorphous boride catalysts for urea-assisted hydrogen production. Full article

(This article belongs to the Section Electrocatalysis)

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15 pages, 3347 KB

Open AccessArticle

Single Step Process for Crystalline Ni-B Compounds

by Mahboobeh Shahbazi, Henrietta Cathey, Natalia Danilova and Ian D.R. Mackinnon

Materials 2018, 11(7), 1259; https://doi.org/10.3390/ma11071259 - 22 Jul 2018

Cited by 14 | Viewed by 4969

Abstract

Crystalline Ni₂B, Ni₃B, and Ni₄B₃ are synthesized by a single-step method using autogenous pressure from the reaction of NaBH₄ and Ni precursors. The effect of reaction temperature, pressure, time, and starting materials on the composition of synthesized products, particle morphologies, and magnetic properties is demonstrated. High yields of Ni₂B (>98%) are achieved at 2.3–3.4 MPa and ~670 °C over five hours. Crystalline Ni₃B or Ni₄B₃ form in conjunction with Ni₂B at higher temperature or higher autogenous pressure in proportions influenced by the ratios of initial reactants. For the same starting ratios of reactants, a longer reaction time or higher pressure shifts equilibria to lower yields of Ni₂B. Using this approach, yields of ~88% Ni₄B₃ (single phase orthorhombic) and ~72% Ni₃B are obtained for conditions 1.9 MPa < P_max < 4.9 MPa and 670 °C < T_max < 725 °C. Gas-solid reaction is the dominant transformation mechanism that results in formation of Ni₂B at lower temperatures than conventional solid-state methods. Full article

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16 pages, 5334 KB

Open AccessArticle

Synthesis of Magnesium Nickel Boride Aggregates via Borohydride Autogenous Pressure

by Mahboobeh Shahbazi, Henrietta E. Cathey and Ian D. R. Mackinnon

Materials 2018, 11(4), 480; https://doi.org/10.3390/ma11040480 - 23 Mar 2018

Cited by 3 | Viewed by 5241

Abstract

We demonstrate synthesis of the ternary intermetallic MgNi₃B₂ using autogenous pressure from the reaction of NaBH₄ with Mg and Ni metal powder. The decomposition of NaBH₄ to H₂ and B₂H₆ commences at low temperatures in the presence of Mg and/or Ni and promotes formation of Ni-borides and MgNi₃B₂ with the increase in temperature. MgNi₃B₂ aggregates with Ni-boride cores are formed when the reaction temperature is >670 °C and autogenous pressure is >1.7 MPa. Morphologies and microstructures suggest that solid–gas and liquid–gas reactions are dominant mechanisms and that Ni-borides form at a lower temperature than MgNi₃B₂. Magnetic measurements of the core-shell MgNi₃B₂ aggregates are consistent with ferromagnetic behaviour in contrast to stoichiometric MgNi₃B₂ which is diamagnetic at room temperature. Full article

(This article belongs to the Special Issue Materials: 10th Anniversary)

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19 pages, 750 KB

Open AccessArticle

Synthesis of Novel Bisindolylmethane Schiff bases and Their Antibacterial Activity

by Syahrul Imran, Muhammad Taha, Nor Hadiani Ismail, Khalid Mohammed Khan, Farzana Naz, Memona Hussain and Saima Tauseef

Molecules 2014, 19(8), 11722-11740; https://doi.org/10.3390/molecules190811722 - 6 Aug 2014

Cited by 96 | Viewed by 9122

Abstract

In an effort to develop new antibacterial drugs, some novel bisindolylmethane derivatives containing Schiff base moieties were prepared and screened for their antibacterial activity. The synthesis of the bisindolylmethane Schiff base derivatives 3–26 was carried out in three steps. First, the nitro group of 3,3'-((4-nitrophenyl)-methylene)bis(1H-indole) (1) was reduced to give the amino substituted bisindolylmethane 2 without affecting the unsaturation of the bisindolylmethane moiety using nickel boride in situ generated. Reduction of compound 1 using various catalysts showed that combination of sodium borohydride and nickel acetate provides the highest yield for compound 2. Bisindolylmethane Schiff base derivatives were synthesized by coupling various benzaldehydes with amino substituted bisindolylmethane 2. All synthesized compounds were characterized by various spectroscopic methods. The bisindolylmethane Schiff base derivatives were evaluated against selected Gram-positive and Gram-negative bacterial strains. Derivatives having halogen and nitro substituent display weak to moderate antibacterial activity against Salmonella typhi, S. paratyphi A and S. paratyphi B. Full article

(This article belongs to the Section Medicinal Chemistry)

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