Catalysts For Hydrogen Evolution Research Articles

Electrosynthesis of Low Pt‐Loaded High Entropy Catalysts for Effective Hydrogen Evolution with Improved Acidic Durability (Adv. Mater. Technol. 20/2023)

Electrosynthesis of Low Pt‐Loaded High Entropy Catalysts for Effective Hydrogen Evolution with Improved Acidic Durability (Adv. Mater. Technol. 20/2023)

Hollow urchin-like FeP as highly efficient hydrogen evolution catalyst

Hollow urchin-like FeP as highly efficient hydrogen evolution catalyst

Hydrogen evolution catalysis by a cobalt porphyrin peptide: A proposed role for porphyrin propionic acid groups

Cobalt microperoxidase-11 (CoMP11-Ac) is a cobalt porphyrin-peptide catalyst for hydrogen (H2) evolution from water. Herein, we assess electrocatalytic activity of CoMP11-Ac from pH 1.0–10.0. This catalyst remains intact and active under highly acidic conditions (pH 1.0) that are desirable for maximizing H2 evolution activity. Analysis of electrochemical data indicate that H2 evolution takes place by two pH-dependent mechanisms. At pH < 4.3, a proton transfer mechanism involving the propionic acid groups of the porphyrin is proposed, decreasing the catalytic overpotential by 280 mV.

3D hydroxylated Ti3C2Tx MXene nanonet architecture supported Pt catalysts for efficient hydrogen evolution

Ti3C2Tx MXene nanonets (MNNs) with 3D fibrous architecture were obtained from Ti3C2Tx MXene nanoplates (MNPs) via surface modifying of alkalization in concentrated KOH solution, which was further combined with carbon nanotube and used as catalyst supports for Pt nanoparticles. By controlling the treatment time of alkalization, the lamellar surface of MNPs was getting into fibration in different extent. The catalytic performances toward hydrogen evolution reaction (HER) of a series of Pt-loaded MNNs catalysts were investigated, in which 1 %Pt-MNNs-9 composite catalyst presented the best hydrogen evolution performance. In detail, 1 %Pt-MNNs-9 with 1 wt.% of Pt loading exhibits an overpotential of 60 mV at 10 mA·cm−2, which is much lower than 1 % Pt-MNPs (274 mV). It also keeps stable performance for long term stability. The enhanced catalytic activity is probably due to the fact that, Ti3C2Tx MNNs with 3D architecture not only possesses abundant sites to anchor Pt nanoaprticles, but also facilitates the mass and charge transfer, which are significantly beneficial to catalytic reaction. The 3D architecture MXene fibers are expected to have widespread applications including but not limited to energy storage/conversion, and catalytic fields.

Fabrication of nitrogen-doped carbon on NiCoP electrocatalyst with flower-like structure for efficient hydrogen evolution reaction in alkaline solution

The development of hydrogen evolution catalysts with low cost, high activity, and outstanding stability has become an urgent need. Herein, we reported a novel and effective strategy for the in situ growth of NiCoP nanoparticles encapsulated in ultrathin nitrogen-doped porous carbon on nickel foam (NiCoP@NC/NF). Compared with NiCoP/NF, the NiCoP@NC/NF presented a much larger electrochemically active surface area (ECSA) (1402.9 cm2 mg−1), more abundant intrinsic HER active sites and lower charge-transfer resistance, leading to superior catalytic activity. The as-prepared NiCoP@NC/NF electrode exhibited extremely low overpotential η10 (77 mV) and Tafel slope (62.1 mV dec−1) for HER in 1.0 M KOH as the electrolyte. Importantly, due to the thin nitrogen-doped carbon layer, NiCoP@NC/NF showed considerably enhanced stability under the harsh conditions of long-term reaction. Density functional theory (DFT) calculations have indicated that the nitrogen-doped carbon of NiCoP@NC/NF permitted moderate trapping of hydrogen atoms and easy desorption of the resulting H2. Such impressive HER performance of the hybrid electrocatalyst is mainly attributed to the collective effects of elemental doping engineering between NC and NiCoP, the enlarged surface area/exposed catalytic active sites, and the lower transfer resistance due to the nitrogen-doping carbon. The present work proposed a controllable and feasible strategy for synthesizing bimetallic phosphides with unique morphology and high HER performance.

Investigation of hydrogen evolution using Na3M2SbO6 (M = Co2+, Ni2+, Cu2+, Zn2+) as photocatalyst

Four honeycomb structured oxides of the type Na3M2SbO6 (M = Co, Ni, C, Zn) were prepared and characterized using a combination of powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). The XPS measurements show that in each case the transition metal cation is divalent, and the Sb is pentavalent. The activity of these as photocatalysts for the direct production of hydrogen from water has been determined. Of these four oxides, Na3Co2SbO6 displayed the highest activity as a Hydrogen Evolution Catalyst (HEC), with an observed H2 evolution rate of 1.323 μmol·hr−1. The rate of hydrogen evolution does not correlate with the measured bandgap, that varied from 2.090(16) eV in Na3Co2SbO6, which allows it to absorb sunlight, to 4.66 eV in Na3Zn2SbO6 that falls outside the visible spectrum. Na3Ni2SbO6 was found to be inefficient as a hydrogen evolution catalyst.

Construction of efficient hydrogen evolution catalyst and analysis of the influence of complexing agent type

In electrocatalytic water decomposition technology, particularly in alkaline solutions, hydrogen evolution with transition metal catalysts has received significant interest. In this study, an efficient HER electrocatalyst with nickel foam base was produced by electrodeposition. Compared with other catalysts, the synthesized CoMo@EDTA electrocatalyst showed significant electrocatalytic activity against HER in alkaline electrolytes. By changing the type of complexing agent, it is found that the overpotential is the lowest after adding EDTA-2Na in 1 mol/l NaOH solution. The overpotential of the CoMo@EDTA catalyst is 29 mV, When the current density is −10 mA/cm2, The outstanding HER performance of CoMo@EDTA electrocatalysts is mainly due to the interaction of molybdenum and cobalt and the effect of complexing agents. After the stability measurement for up to 6 h, the catalyst has a minimal overpotential loss, indicating that the catalyst has excellent stability. This work provides a useful pathway for the application of transition metals in hydrogen evolution electrocatalysts.

MoO2-based cost effective catalyst for hydrogen evolution via water splitting

MoO2-based cost effective catalyst for hydrogen evolution via water splitting

Catalysts for hydrogen evolution in universal-pH medium: Construction and structural optimization of Ni3S2/Co9S8/WS2 interface synergies

The performance of heterostructure nanomaterials depends on both the individual components characteristics and the interfaces synergistic effect. In this paper, a high-activity universal-pH HER catalyst, Ti felt supported nanoporous Ni3S2/Co9S8/WS2 (NiCoW-S) is synthesized by electrodeposition and vulcanization. Compared with Ni3S2/Co9S8, Ni3S2/Co9S8/WS2 heterostructure catalyst exhibits enhancement of intrinsic catalytic active center, charge transfer rate and stability in a wide pH range. Benefiting from the 3D porous structure and high-density heterostructure active edge sites, NiCoW-S shows good stability. And Moreover, it only needs 35 and 145 mV to reach 10 mA cm−2 in 0.5 M H2SO4 and 1.0 M KOH, respectively. Based on the experimental analysis, the favorable synergistic effect of metal components and the formation of sulfur vacancies can enhance the conductivity of electron transfer, which promotes electron transfer at the active heterogeneous interface. It provides a reference for designing of advanced metal sulfide heterostructure for hydrogen production in the future.

Theoretical expectation and experimental investigation on the feasibility of N-doped Ni2P as highly active hydrogen evolution catalyst

In this paper, N-doped Ni2P (N-Ni2P) as a catalyst for hydrogen evolution was proposed. Firstly, the feasibility of N atom doping was calculated by density functional theory (DFT). Ni top site, Ni bridge site, Ni hollow site and P top site were calculated for Ni2P (001) and N-Ni2P (001). The results confirm that N atom doping can make the Gibbs free energy (ΔGH∗) closer to thermal neutrality (ΔGH∗ = 0) and move the d-band center away from Fermi level. Besides, charge density difference pattern and bader charge indicate N atom doping regulate the charge structure of the catalyst surface. Based on the guidance of DFT calculation results, Ni2P and N-Ni2P catalysts were also experimentally synthesized. It is revealed that the N-Ni2P can achieve cathodic current densities of 10 mA cm−2 and 100 mA cm−2 at overpotentials of 110 mV and 302 mV in 1.0 M KOH and 82 mV and 235 mV in 0.5 M H2SO4, respectively. This work shows that it is feasible to increase HER performance by modifying Ni2P catalyst with N doping.

Construction of Co9S8/MoS2/Ni2P double S-scheme heterojunction for enhanced photocatalytic hydrogen evolution

Rational design of composite catalysts with efficient charge separation and transfer and good light collection ability is of great significance to achieve high photoelectrochemical conversion efficiency. In this paper, a Co9S8/MoS2/Ni2P dual S-scheme heterojunction photocatalyst was successfully synthesized by a simple sulfidation and hydrothermal method. The optimized Co9S8/MoS2/Ni2P composite with hierarchical structure, large surface area and numerous reactive active sites showed a good photocatalytic hydrogen evolution rate of 5.69 mmol g−1 h−1, which is 2.28, 4.12 and 10.74 times higher than that of pure Co9S8, MoS2 and Ni2P, respectively. A combination of time-resolved photoluminescence (TRPL) spectroscopy, valence band XPS (VB-XPS), ultraviolet photoelectron spectroscopy (UPS), and density-functional theory (DFT) calculations confirms that the formation of the Co9S8/MoS2/Ni2P double S-scheme greatly facilitates charge migration and spatial separation, and improves the oxidation and reduction ability. This work will provide insights into the development of PBA-based dual S-scheme heterojunction catalysts for photocatalytic hydrogen evolution.

Electrodeposited Ni−Co−P Triple-Layered Structure as A Robust and Durable Electrocatalyst for Hydrogen Evolution

Designing Earth-abundant, cost-effective catalysts for hydrogen evolution via water splitting is essential for hydrogen generation. Adding a third metal element to binary phosphides provides the opportunity to tune their morphology, crystalline and electronic structures and thus their electrocatalytic properties. In this study, a hierarchical crystalline/amorphous Ni−Co−P compound is prepared on nickel foam (NF) with different nickel to cobalt ratio by one-step electrodepositing technique. The Ni−Co−P/NF is composed of metallic Co and amorphous phosphides. It has hierarchical morphology, consisting of ∼800 nm spherical particles in the bottom layer, ∼1.5 μm spherical particles in the middle layer, and staggered network structure on the top layer. The Ni−Co−P/NF electrode exhibits superior hydrogen evolution reaction (HER) catalytic activity in the alkaline solution, which requires only 72 mV for delivering 10 mA cm−2. More importantly, the Ni−Co−P/NF catalyst sustains the current density of 20 mAcm−2 for 53 h with negligible degradation in overpotential which shows remarkable electrochemical stability.

Fabrication of micro/nano wettability MoS2 hydrogen evolution electrocatalyst based on femtosecond laser

The process of hydrogen production through water electrolysis involves ionic interactions and the dynamic process of hydrogen bubble formation on the electrode surface. In this study, we employed a combination of femtosecond laser and hydrothermal synthesis to fabricate a novel MoS2 electrode. The double-scale structure of this substrate increases its specific surface area, facilitating the presence of active sites for the hydrogen evolution reaction. The growth of nano-scale catalyst further enhances wettability, promoting rapid detachment of gas bubbles and replenishment of water. This method not only facilitates ionic interactions but also accelerates the formation of macroscopic bubbles. Under alkaline conditions, electrode achieved an impressive current density of 10 mA cm−2 with a low overpotential of only 99 mV. This novel MoS2 hydrogen evolution catalyst holds practical value, paving the way for the design of more efficient and stable electrocatalysts.

Development of a Small Molecule Hydrogen Evolution Catalyst

Based on prior work done by Diane K. Smith et al on redox responsive 3 hydrogen bond array dimers, a fundamental investigation on the nature of proton coupled electron transfer (PCET) was done by surveying a series of new electroactive “host” H-bond dimers. In these dimers, electron transfer should induce proton transfer across a H-bond, increasing the overall strength of hydrogen bond binding the “guest” and “host”. In particular, the goal was to investigate how electrochemical behavior and binding strength changes as the relative acidity of the electro-inactive “guest” changes in a 2-hydrogen bond array. For this task, amido pyridinium derivatives will be used as the redox active "hosts" and a series of different carboxylic acid, 2-hydroxypyridine, and amide derivatives as the electro-inactive "guests". Unexpectedly, in the presence of carboxylic acids, the amido pyridinium acts as a hydrogen evolution catalyst. During guest host cyclic voltammogram (CV) titrations, there was a large anodic shift of 500 mV and a catalytic increase in current, which is characteristic of an EC mechanism (figure 2). A series of investigations into this mechanism were done following the initial discovery, including scan rate and concentration dependence CV’s, spectro-electrochemical studies, bulk electrolysis, DEMS, and DFT calculations. These studies allowed us to propose the mechanism below (figure 1) for hydrogen evolution. This presentation will detail our efforts to characterize this hydrogen evolution catalyst, the relevance of small molecule hydrogen evolution catalyst, and how we intend to modify it for synthetic purposes.Figure 1 (left image): Reduction of pyridinium amide with and without guests and proposed mechanism of hydrogen evolutionFigure 2 (right image): CV of pyridinium amide in the presence of dodecanoic acid Figure 1

Enhancing Effect of Boron-Doping on the Activity of Nife-MOF-74 Towards Oxygen Evolution Reaction in Alkaline

Water splitting has drawn significant attention due to the capability of mass-producing hydrogen, which is considered a promising alternative to fossil fuels in the future.[1] The development of electrochemical energy conversion and storage technologies, such as water electrolyzers, metal-air batteries, and regenerative fuel cells, is of great importance to support the transition to clean and renewable energy.[2] Based on the merits of high surface area, 3D periodic porous structure, large porosities, diverse composition and well-defined metal centers, metal–organic frameworks (MOFs) and their derivatives have been widely exploited as OER electrocatalysts.[3]However, MOFs have some limitation to be used as a OER catalysts, considering their poor stabilities (in water, especially basic/acidic conditions) and low electrical conductivities. Incorporation of boron atoms into an aromatic carbon framework offers a wide variety of functionalities. [4] In this work, the flower-like bimetallic NiFe-MOF-74 dopped with boron were fabricated, and they exhibit superior catalytic activity with a very low overpotential of 318 mV for OER at a laboratory grade current density of 10 to 100 mA/cm2 and fast reaction kinetics with a small Tafel slope of 89 mV dec-1 in 1.0 M KOH using a catalyst fabrication process that is scalable to commercial levels. Additional work is required to demonstrate current densities at commercial levels. Reference [1] L. Fan, Z. Kang, M. Li, D. Sun, Recent progress in pristine MOF-based catalysts for electrochemical hydrogen evolution, oxygen evolution and oxygen reduction, Dalton Trans. 50 (2021) 5732–5753. https://doi.org/10.1039/D1DT00302J.[2] Bimetallic metal–organic frameworks and MOF-derived composites: Recent progress on electro- and photoelectrocatalytic applications - ScienceDirect, (n.d.). https://www.sciencedirect.com/science/article/pii/S0010854521005385 (accessed April 27, 2022).[3] J. Du, F. Li, L. Sun, Metal–organic frameworks and their derivatives as electrocatalysts for the oxygen evolution reaction, Chem. Soc. Rev. 50 (2021) 2663–2695. https://doi.org/10.1039/D0CS01191F.[4] Y. Xie, Z. Meng, T. Cai, W.-Q. Han, Effect of Boron-Doping on the Graphene Aerogel Used as Cathode for the Lithium–Sulfur Battery, ACS Appl. Mater. Interfaces. 7 (2015) 25202–25210. https://doi.org/10.1021/acsami.5b08129.

Hydrogen Catalysis By Macrocyclic Pyrrole Catalysts

We have designed hangman porphyrins for the study of hydrogen evolution catalysis. The hangman constructs utilize a pendant acid/base functionality within the secondary coordination sphere that is “hung” above the redox platform onto which the substrate binds. In this way, the delivery of a proton can precisely be controlled to substrate bonded to the metal of the macrocycle, thus ensuring efficient coupling between the proton and electron. Beyond the benefits of proton-coupled electron transfer (PCET), we have uncovered the impactful role of co-catalysts on electrocatalytic hydrogen production at the macrocyclic platform. Hydrogen evolution from a weak acid, acetic acid, occurs at extremely high rates in the presence of tertiary amine as a co-catalyst. These findings reveal controlled proton delivery and co-substrates as important design principles for creating efficient hydrogen evolution catalysts.

Relating Near-Surface Ti Electrode Structure with Electrochemical Nitrate Reduction Performance Via Synchrotron X-Ray Characterization

The global nitrogen cycle has been severely skewed since the widespread adoption of the Haber-Bosch process to produce ammonia (NH3). Currently, removal of reactive nitrogen (inorganic forms besides N2) from the environment lags behind its production and emission to the environment. Nitrate is one of the most prevalent waterborne nitrogen pollutants and, in its excess, threatens the health of ecosystems. Enabling a sustainable food-energy-water nexus requires feeding a growing population while minimizing environmental impacts. Therefore, selective electrochemical nitrate reduction (NO3RR) to NH3 can couple water purification and NH3 production, helping offset the energy- and carbon-intensive Haber Bosch process. NH3 recovery from emissions could contribute over 20 million tons N per year by 2050 (~ 10% of projected N demand).Noble and transition metal catalysts including single metals (e.g., Pt, Rh, Ru, Ir, Pd, Cu, Ag, Au)[1,2] and alloys (e.g., CuNi)[3] have been studied for NO3RR. Notably, under acidic conditions, polycrystalline titanium has been demonstrated to display robust and efficient NO3RR.[4] Ti is corrosion-resistant, a poor hydrogen evolution catalyst, and a readily available, abundant metal. However, under acidic and reducing conditions, Ti forms a water-stable hydride (TiHx, 0<x≤2).[5] It remains unclear how the degree of surface hydride formation – which alters the physical and electronic properties of the electrode surface – impacts NO3RR performance. Thus, rationally implementing Ti-catalyzed NO3RR requires improved understanding of how near-surface Ti-hydride forms and influences NO3RR activity and selectivity.In this work, we show that near-surface Ti-hydride formation is a function of the duration and magnitude of applied NO3RR potential. A combination of ex situ grazing-incidence X-ray diffraction (GIXRD – probes long-range, crystalline order) and X-ray absorption spectroscopy (XAS – probes short-range, atom-specific probe into local coordination environments) enabled quantitative near-surface characterization of Ti-hydride electrodes. Through electrochemical testing and density functional theory calculations, we investigated the role near-surface Ti-hydride may play in electrochemical nitrate conversion. Our results preliminary suggest that near-surface hydride content plays a relatively minor role in steering NO3RR performance compared to applied potential and electrolyte effects. In addition, we are performing ongoing in situ GIXRD and XAS measurements to interrogate the transient nature and interplay of near-surface hydride formation and NO3RR. Put in context, our results help prioritize how Ti-catalyzed NO3RR processes can be optimized for electrified ammonia production and wastewater remediation.[1] G. E. Dima, A. C. A. de Vooys, M. T. M. Koper, Journal of Electroanalytical Chemistry 2003, 554–555, 15–23.[2] G. E. Dima, G. L. Beltramo, M. T. M. Koper, Electrochimica Acta 2005, 50, 4318–4326.[3] Y. Wang, A. Xu, Z. Wang, L. Huang, J. Li, F. Li, J. Wicks, M. Luo, D.-H. Nam, C.-S. Tan, Y. Ding, J. Wu, Y. Lum, C.-T. Dinh, D. Sinton, G. Zheng, E. H. Sargent, J. Am. Chem. Soc. 2020, 142, 5702–5708.[4] J. M. McEnaney, S. J. Blair, A. C. Nielander, J. A. Schwalbe, D. M. Koshy, M. Cargnello, T. F. Jaramillo, ACS Sustainable Chem. Eng. 2020, 8, 2672–2681.[5] Y. Liu, Z. H. Ren, J. Liu, R. F. Schaller, E. Asselin, J. Electrochem. Soc. 2019, 166, C3096–C3105.

Facile self-oxidized Ni nano-foam as high-performance catalyst for hydrogen and oxygen evolution

Facile self-oxidized Ni nano-foam as high-performance catalyst for hydrogen and oxygen evolution

Effect of different crystalline phase of TiO2 on the catalytic activity of Ru catalysts in hydrogen evolution under acidic and alkaline media

Designing highly active and durable catalysts is considered to be crucial for enhancing hydrogen evolution reaction (HER) from water electrolysis. Although some studies indicate that anatase TiO2 is a promising candidate for electrolytic hydrogen evolution reaction, the influence of different crystalline phases of TiO2 on the supported Ru catalysts for electrocatalytic HER performance is rarely systematically explored. Herein, a series of Ru/TiO2-X (X = R (Rutile), A (Anatase), and P25) catalysts were prepared to investigate the influence of the rutile and anatase phases of TiO2 on the catalytic activity of Ru catalysts in HER. The findings demonstrate that the HER activity is much affected by the variation of the titania structure, when other factors are kept constant. The 15Ru/TiO2-R-H2 has superior HER performance with a small overpotential of 63 mV to achieve a current density of 10 mA cm−2 in acidic electrolyte and 99 mV in alkaline electrolyte compared to 15Ru/TiO2-A-H2 and 15Ru/TiO2-P25-H2. This might be attributed to the faster electron transfer and lower Fermi level caused by the oxygen vacancy (VO) and strong metal-support interaction (SMSI), along with the exposure of active sites afforded by the highly dispersed ruthenium nanoparticles on the rutile TiO2. Our results indicate that the presence of rutile TiO2 support alone is adequate to maintain Ru in its most active form and make it a more performing catalyst, compared to anatase titania and P25.

Colloid synthesis of Ni12P5/N, S-doped graphene as efficient bifunctional catalyst for alkaline hydrogen evolution and triiodide reduction reaction

Designing high-efficient bifunction catalysts with excellent catalytic activity and enhanced charge-transfer capability in both alkaline hydrogen evolution reaction (HER) and triiodide reduction reaction (IRR) is of utmost significance to advance the development of green hydrogen production and photovoltaics, respectively, yet remains a crucial challenge. Here, highly dispersed and small-sized Ni12P5 nanocrystals with narrow size distribution was well attached on the surface of N, S co-doped graphene (Ni12P5/NSG) by the facile hot-injection method. As expected, the optimized Ni12P5/NSG requires a relatively low overpotential of 132.94 ± 0.08 mV to deliver a current density of 10 mA cm−2 in alkaline condition, accompanied with remarkable long-time durability with negligible attenuation over 50 h. Density functional theory (DFT) calculations revealed that the positively synergic effect between Ni12P5 and NSG are in favor of modulating the rate determining step of the dissociation of H2O to *(OH-H), thereby upgrading its HER activity. When used as the counter electrode catalyst for IRR in DSSCs, the resultant Ni12P5/NSG exhibits extraordinary Pt-like catalytic activity and well electrochemical stability in iodide-based electrolyte, delivering a high photoelectric conversion performance (PCE) comparable to Pt. The improved PCE can be attributed to the accelerated interfacial charge-transfer capability around active sites for facilitating the reaction kinetics of IRR, as demonstrated by DFT calculations. This work provides an effective strategy for synthesizing cost-effective composites with multi-active sites and offering valuable insight into the structure-performance relationship, which is conducive to guide the synthesis of promising catalysts in the energy conversion field.